7Th International Congress on the Application of Raman Spectroscopy in Art and Archaeology

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BOOK OF ABSTRACTS

7th International Congress on the Application of Raman Spectroscopy in Art and Archaeology

2-6 September 2013

7th International Congress on the Application of Raman Spectroscopy in Art and Archaeology

Book of Abstracts

7th International Congress on the Application of Raman Spectroscopy in Art and Archaeology Ljubljana, Slovenia, 2th–6th September 2013 Book of Abstracts 7th International Congress on the Application of Raman Spectroscopy in Art and Archaeology (RAA 2013), Ljubljana (Slovenia), 2th–6th September 2013

Publisher: Institute for the Protection of Cultural Heritage of Slovenia Editors: Polonca Ropret, Nadja Ocepek Editorial Board: Klara Retko, Lea Legan, Tanja Špec, Črtomir Tavzes Print: Birografika BORI d.o.o. Copies: 400

Ljubljana 2013

No part of the material protected by this copyright may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any storage or retrieval system, without written permission from the copyright owners.

The publication is published with the financial support of the Ministry of Culture, and is not payable.

REPUBLIC OF S LOVENIA  MINISTRY OF CULTURE

CIP - Kataložni zapis o publikaciji Narodna in univerzitetna knjižnica, Ljubljana 543.424.3:7(082) 543.424.3:902(082)

INTERNATIONAL Congress on the Application of Raman Spectroscopy in Art and Archaeology (7 ; 2013 ; Ljubljana) Book of abstracts / 7th International Congress on the Application of Raman Spectroscopy in Art and Archaeology, Ljubljana (Slovenia), 2th-6th September 2013 ; [editors Polonca Ropret, Nadja Ocepek]. - Ljubljana : Institute for the Protection of Cultural Heritage of Slovenia, 2013

ISBN 978-961-6902-38-0 1. Ropret, Polonca, kemik 268489728

RAA 2013 6 The use of Raman spectroscopy for identifying and studying the material component of the objects of art and antiquities has flourished in recent years. The increasing importance of the application of Raman spectroscopy in art and archaeology is illustrated by an increasing number of research papers published each year, and by the scientific conferences and sessions that have been dedicated to this research area in the past decade. The RAA conferences promote Raman spectroscopy and play an important role in the increasing field of its application in Art and Archaeology. The RAA is an established biennial international event. It brings together studies from diverse areas and represents dedicated work on the use of this technique in connection to the fields of art-history, history, archaeology, palaeontology, conservation and restoration, museology, etc. Furthermore, the development of new instrumentation, especially for non-invasive measurements, has received a great attention in the past years. These prominent, international events have a long tradition. Previously they were held in London (2001), Ghent (2003), Paris (2005), Modena (2007), Bilbao (2009), Parma (2011), and this year (2013) in Ljubljana.

The RAA 2013 conference received over 100 high quality contributions from different research laboratories all over the world, and this book of abstracts presents their latest advancements. One of the important topics is studies of deterioration induced by different environmental factors, such as biodeterioration, pollution, light and humidity exposure. The outcomes of these studies can give important information for designing safe conservation – restoration treatments and help in creating a better environment for cultural heritage objects, for their storage and display, all contributing to increasing of its sustainability. A great number of research contributions are presenting the latest achievements in the characterisation of traditional organic colorants by introducing new solutions for Surface enhanced Raman spectroscopic studies. This is an important topic that contributes to understanding not only the composition of the organic colorants, but also their production processes. The advancements in metals characterisation give important information to understanding of their corrosion processes and/or deliberate patinations by artists, which can give important input in designing further corrosion inhibition processes. A special topic is dedicated to the archaeometry research, from characterisation of ancient artefacts, their degradation processes, to finding possible solutions for their preservation. New, presented knowledge on gemstones characterisation, provenance, authenticity research, and furthermore, forensics applications, all attest of the wide applicability of Raman spectroscopy. The latest innovations in Raman instrumentation is presented by well – known companies in the field of Raman instruments, with a special emphasis in the development of portable, non-invasive instruments. Many research laboratories are taking the advantage of non-invasive instruments in order to keep the full integrity of works of art. However, the interpretation of the results is often challenging, which gives scientific contributions dealing with these questions a special, important place. Finally, the importance of a comprehensive Raman database is emphasised, and the latest work of the Infrared and Raman Users Group (IRUG) is presented, a database which we all help creating, and which can help in solving many questions that we all face.

We wish to thank all of the authors who submitted their latest research results and helped creating the scientific program of the RAA 2013 conference, as well as this Book of Abstracts.

On behalf of the organizing committee, Polonca Ropret, Research Institute, Conservation Centre, Institute for the Protection of Cultural Heritage of Slovenia

7 Book of Abstracts Scientific Committee

Dr. Polonca Ropret Research institute, Conservation Centre, Institute for the Protection of Cultural Heritage of Slovenia

Dr. Danilo Bersani Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Parma, Italy

Prof. Dr. Juan Manuel Madariaga Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country, Spain

Prof. Dr. Peter Vandenabeele Research group in Archaeometry, Department of Archaeology, Ghent University, Belgium

Prof. Dr. Howell G. M. Edwards Centre for Astrobiology and Extremophiles Research, School of Life Sciences, University of Bradford, UK

Prof. Dr. Pietro Baraldi Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Italy

Dr. Sandrine Pagès-Camagna Centre de Recherche et de Restauration des Musées de France (C2RMF), France

Dr. Francesca Casadio The Art Institute of Chicago, USA

RAA 2013 8 Organizing Committee

Janez Kromar Director of Conservation Centre, Institute for the Protection of Cultural Heritage of Slovenia

Jernej Hudolin Head of Restoration Centre, Conservation Centre, Institute for the Protection of Cultural Heritage of Slovenia

Dr. Polonca Ropret Head of Research Institute Conservation Centre, Institute for the Protection of Cultural Heritage of Slovenia

Dr. Črtomir Tavzes Research Institute, Conservation Centre, Institute for the Protection of Cultural Heritage of Slovenia

Tanja Špec Research Institute, Conservation Centre, Institute for the Protection of Cultural Heritage of Slovenia

Lea Legan Research Institute, Conservation Centre, Institute for the Protection of Cultural Heritage of Slovenia

Klara Retko Research Institute, Conservation Centre, Institute for the Protection of Cultural Heritage of Slovenia

Nadja Ocepek Research Institute, Conservation Centre, Institute for the Protection of Cultural Heritage of Slovenia

9 Book of Abstracts List of accepted works with corresponding authors

PL: Plenary Lecture OP: Oral Presentation P: Poster Presentation

Monday, September 2, 2013 ORAL SESSION 1 Deterioration studies and organic materials

Raman Spectroscopy of Extremophilic Howell G. M. Edwards PL1 20 Biodeterioration: An Interface between Archaeology and the Preservation of Cultural Heritage

Identification of endolithic survival strategies on stone Annalaura Casanova Municchia OP1 22 monuments

FT-Raman analysis of historical cellulosic fibres Katja Kavkler OP2 24 infected by fungi

Combined FT-Raman and Fibre-Optic Reflectance Anuradha Pallipurath OP3 26 Spectroscopic Characterisation of Simulated Medieval Paint Films: a Chemometric Study of the Effects of Natural and UV-Accelerated Ageing

Study of malachite degradation in easel (model) Tanja Špec OP4 27 paintings by spectroscopic analysis

Portable and laboratory analysis to diagnose the Juan Manuel Madariaga OP5 29 formation of efflorescence on walls and wall paintings of Insula IX, 3 (Pompeii, Italy)

Decorated plasterwork in the Alhambra investigated by Ayora-Cañada María José OP6 31 Raman spectroscopy: field and laboratory comparative study

Multi-technical approach for the study of French Céline Daher OP7 33 Decorative Arts furniture and luxury objects

POSTER SESSION 1

Deterioration of lead based pigments on a fresco: a Ilaria Costantini P1 35 micro-Raman investigation

Investigation of colour layers in easel (model) paintings Klara Retko P2 36 influenced by different ageing processes

RAA 2013 10 Identification of copper azelate in 19th century Vanessa Otero P3 38 Portuguese oil paintings: Characterisation of metal soaps by Raman Spectroscopy

Raman study of pigment degradation due to acetic acid Alessia Coccato P4 40 vapours

Investigating the sources of degradation in corroded Thiago Sevilhano Puglieri P5 42 lead sculptures from Oratory Museum (Museu do Oratório), Brazil

Evora Cathedral: Pink! Why not? Ana Teresa Caldeira P6 44

Study of red biopatina composition on sandstone Juan Manuel Madariaga P7 46 from a historical war Fort in La Galea (Biscay, north of Spain) by means of single point focusing Raman analysis and Raman Imaging combined with microscopic observation

Raman and non invasive IR analyses of natural Céline Daher P8 48 organic coatings: application to historical violin varnishes

Characterization of green copper organometallic Carlotta Santoro P9 50 pigments and understanding of their degradation process in European easel paintings

Optical Microscopy and Micro-Raman studies of The Ewa Pięta P10 51 Hans Memling’s Triptych “The Last Judgment”

Non-destructive micro-Raman and XRF investigation on parade saddles of italian renaissance Pietro Baraldi P11 52

Phoenicians preferred red pigments: micro-Raman Cecilia Baraldi P12 54 investigation on some cosmetics found in Sicily archaeological sites

Raman microscopy and X-ray fluorescence for the rediscovering of polychromy and gilding on classical Pietro Baraldi P13 56 statuary in the Galleria degli Uffizi

Raman spectroscopic investigation of black pigments Alessia Coccato P14 58

Raman Spectroscopy and SEM-EDS Studies Revealing Kepa Castro P15 60 Treatment History and Pigments of the Government Palace Tower Clock in Helsinki Empire Senate Square Mohsen Ghanooni P16 62 Feasibility Study of Portable Raman Spectroscopy for Characterization of Ground Material of Easel Paintings (Case Study: Sradar As’ad-e Bakhtiary Painting of Kamal-al Molk)

11 Book of Abstracts The Sibyls from the church of San Pedro Telmo: a Marta S. Maier P17 64 spectroscopic investigation

Pigment identification of illuminated medieval Debbie Lauwers P18 66 manuscripts by means of a new, portable Raman equipment

Micro-Raman identification of pigments on wall Petra Bešlagić P19 68 paintings: characterisation of Langus and Sternen’s palettes

ORAL SESSION 2

RENISHAW: New Methods in Raman Spectroscopy – Josef Sedlmeier OP8 70 Combining Other Microscopes for mineral and pigment analysis

HORIBA JOBIN YVON: Advances in Raman Romain Bruder OP9 72 instrumentation: explore new boundaries in Art and Archaeology

NORDTEST: A portable 1064 nm Raman spectrometer Alessandro Crivelli OP10 73 for analysis of cultural heritage items

BAYSPEC: Novel 1064 nm Dispersive Raman Lin Chandler OP11 75 Spectrometer and Raman Microscope for Non-invasive Pigment Analysis

Tuesday, September 3, 2013 ORAL SESSION 3 Surface Enhanced Raman Spectroscopy in Art and Archaeology

Surface-Enhanced Raman Spectroscopy in Art and Marco Leona PL2 78 Archaeology

TLC-SERS of mauve, the first synthetic dye Maria Vega Cañamares OP12 80

New photoreduced substrate for SERS analysis of Klara Retko OP13 82 organic colorants

Laser Ablation Surface-enhanced Raman Pablo S. Londero OP14 84 Microspectroscopy

RAA 2013 12 Silver colloidal pastes for the analysis via Surface Ambra Idone OP15 86 Enhanced Raman Scattering of colored historical textile fibers: some morphological and spectroscopic considerations

Surface enhanced Raman spectroscopy for dyes and Brenda Doherty OP16 88 pigments – Can non-invasive investigations become a reality?

Surface Enhanced Raman Scattering of organic dyes on N. R. Agarwal OP17 90 gold substrates prepared by pulsed laser ablation

Combining SERS with chemometrics: a promising Rita Castro OP18 92 technique to assess historical samples with historically accurate reconstructions

Characterization and Identification of Asphalts in María Lorena Roldan OP19 94 Works of Art by SERS complemented by GC-MS, FTIR and XRF

Study of Raman scattering and luminescence Francesca Rosi OP20 95 properties of orchil dye for its nondestructive identification on artworks

POSTER SESSION 2

Application to historical samples of in situ, Ambra Idone P20 96 extractionless SERS for dye analysis

Application of surface-enhanced Raman spectroscopy Federica Pozzi P21 98 (SERS) to the analysis of red lakes in French Impressionist and Post-Impressionist paintings

Surface-Enhanced Raman Spectroscopy (SERS) Chiara Zaffino P22 100 of historical dyes on textile fibers: evaluation of an extractionless treatment of samples

Suitability of Ag-agar gel for the micro-extraction of Elena Platania P23 102 organic dyes on different substrates: the case study of wool, silk, printed cotton and panel painting mock-ups

PB15 polymorphic distinction in paint samples Jolien van Pevenage P24 104 by combining micro-Raman spectroscopy and chemometrical analysis

13 Book of Abstracts First identification of the painting technique in 18th Oana-Mara Gui P25 106 Century Transylvanian oil paintings using micro- Raman and SERS

Organic materials in oil paintings and canvas revealed Oana-Mara Gui P26 108 by SERS

Characterization of SOPs in acrylic and alkyd paints by Marta Angehelone P27 110 means of µ-Raman spectroscopy

Synthetic Polymers and Cultural Heritage. Analytical Margarita San Andrés P28 112 approach by Raman spectroscopy

Raman monitoring of the sol-gel process on OTES/ L. de Ferri P29 114 TEOS hybrid sols for the protection of historical glasses

Possible differentiation with Raman spectroscopy A. R. De Torres P30 116 between synthetic and natural ultramarine blues. Comparative analysis with the blue pigment of a painting of R. Casas (1866–1932)

Raman monitoring of the polymerization reaction of a Laura Bergamonti P31 118 hybrid protective for wood and paper

Reference Raman data of the artist palette – tool for in- Iwona Żmuda-Trzebiatowska P32 119 situ investigation of J. Matejko (1838–1893) paintings

Material analysis of the Manueline Foral Charters of António Candeias P33 121 Lousã and Marvão

Materials and gilding techniques on plasterwork in the Domínguez Vidal Ana P34 123 Alhambra (Granada, Spain)

Characterization of gypsum and anhydrite ground António Candeias P35 125 layers on 15th and 16th centuries Portuguese painting by Raman Spectroscopy, Micro X-ray diffraction and SEM-EDS

Identification of deteriorated pigments on wall Katja Kavkler P36 128 paintings from Lutrovska klet, Sevnica, Slovenia, using Raman spectroscopy and SEM-EDS

Characterization of middle age mural paintings: in Julene Aramendia P37 130 situ Raman spectroscopy associated with different techniques

RAA 2013 14 Raman microspectroscopic identification of pigments Maja Gutman P38 132 of newly discovered gothic wall paintings from the Dominican Monastery in Ptuj (Slovenia)

Shot Noise Reduction through Principal Components J. J. González-Vidal P39 134 Analysis

ORAL SESSION 4 Raman for characterization of metal artefacts

Raman investigation of artificial patinas on recent Tadeja Kosec OP21 135 bronze, protected by different azole type inhibitors in outdoor environment

Micro-Raman Investigation on corrosion of Pb-Based Giorgia Ghiara OP22 136 Alloy Replicas

Conservation diagnosis of weathering steel sculptures Julene Aramendia OP23 138 using a new Raman quantification imaging approach

Raman study of the salts attack in archaeological Kepa Castro OP24 140 metallic objects of the Middle Age: The case of Ereñozar castle (Bizkaia, Spain)

Thursday, September 5, 2013 ORAL SESSION 5 Raman Spectroscopy in Archaeometry

The Contribution of Archaeometry to Understanding Juan Manuel Madariaga PL3 143 of the Past Effects and Future Changes in the World Heritage Site of Pompeii (Italy)

Raman spectroscopy applied to the study of Cretaceous Paulo T. C. Freire OP25 145 fossils from Araripe Basin, Northeast of Brazil

Raman spectroscopic analyses of~75. 000 year old stone tools from Middle Stone Age deposits in Sibudu Linda C. Prinsloo OP26 147 Cave, KZN, South Africa

Raman Spectroscopy in Archaeometry: multi-method approaches and in situ investigations: advantages and Peter Vandenabeele OP27 149 drawbacks

15 Book of Abstracts Spectroscopic Analysis of Chinese Porcelain Excavated Jolien van Pevenage OP28 150 in Clairefontaine (Belgium): Pigment Identification and Dating

Characterization of ancient ceramic using micro- Laura Medeghini OP29 152 Raman spectroscopy: the cases of Motya (Italy) and Khirbetal-Batrawy (Jordan)

Hispano-Moresque architectural tiles from the Vânia S. F. Muralha OP30 154 Monastery of Santa Clara-a-Velha, in Coimbra, Portugal: a µ-Raman study

The blue colour of glass and glazes in Swabian contexts Maria Cristina Caggiani OP31 155 (South of Italy): an open question

Spectroscopic characterisation of crusts interstratified Antonio Hernanz OP32 157 with prehistoric paintings preserved in open-air rock art shelters

POSTER SESSION 4

Micro-Raman on Roman glass mosaic tesserae Claudia Invernizzi P40 159

Raman and IR Spectroscopic Study of Vitreous Doris Möncke P41 160 Artefacts from the Mycenaean to Roman Period: Glassy Matrix & Crystalline Pigments

The detection of Copper Resinate pigment in works of Irene Aliatis P42 162 art: contribution from Raman spectroscopy

Micro-Raman and internal micro-stratigraphic Clauda Pelosi P43 164 analysis of the paintings materials in the rock- hewn church of the Forty Martyrs in Şahinefendi, Cappadocia (Turkey)

Vibrational characterization of the new gemstone Erica Lambruschi P44 166 Pezzottaite

FTIR-ATR and ESEM of wall paintings from the tomb Mohamed Abd El Hady P45 168 of Amenemonet (TT277), Qurnet Murai necropolis, Luxor, Egypt

Physico-chemical characteristics of Predynastic pottery Mohamed Abd El Hady P46 170 objects from Maadi – Egypt

RAA 2013 16 Raman Database of Corrosion Products as a powerful Serena Campodonico P47 171 tool in art and archaeology

MicroRaman as a powerful non-destructive technique Serena Campodonico P48 173 to characterize ethonological objects from D’Albertis Castle Museum of World Cultures in Genova

Micro ATR-IR study of pollutions affecting radiocarbon Ludovic Bellot-Gurlet P49 175 dating of ancient Egyptian mummies

Raman Scanning of Biblical Period Ostraca Arie Shaus P50 176

Analyses of pigments from 4th century B.C. the Cristina Aibéo P51 178 Shushmanets tombs in Bulgaria

Raman Spectroscopic Study of the Formation of Fossil Margarita San Andrés P52 179 Resins Analogs

Pigments from Templo Pintado (Pachacamac, Perú) Dalva Lúcia Araújo de Faria P53 181 investigated by Raman Microscopy

Lithic tools raw materials recognition by Raman Sonia Murcia-Mascaros P54 183 spectroscopy of Palaeolitihic artifacts

Raman characterization on historical mortar. Crossing Dorotea Fontana P55 184 data with XRD and Color Measurements

Roman ceramics from Vicofertile (Parma, Italy): Elisa Adorni P56 185 micro-Raman study of the heat diffusion during the production process

Raman spectroscopic study on ancient glass Pisutti Dararutana P57 187 beads found in Thailand archaeological sites

Identification of Neolithic jade found in Switzerland Marie Wörle P58 188 studied using Raman spectroscopy: Jadeite – vs. Omphacite – jade

Raman Spectroscopy as useful tools for the Simona Raneri P59 190 gemmological certification and provenance determination of sapphires

Authentication of ivory by means of 1064 nm Raman Alessandro Crivelli P60 191 spectroscopy and X-ray fluorescence spectrometry

17 Book of Abstracts ORAL SESSION 6 Characterization of Gems and Forensic Applications

Characterization of emeralds by micro-Raman Danilo Bersani OP33 192 spectroscopy Raman micro spectroscopy of inclusions in gemstones Miha Jeršek OP34 194 from a chalice made in 1732

Spectroscopic investigation: impurities in azurite as Lucia Burgio OP35 196 provenance markers

Implementation of scientific methods of fine art Barbara Łydżba-Kopczyńska OP36 198 authentication into forensics procedures: the case study of “Bolko II Świdnicki” by J.J Knechtel

Raman analysis of multilayer automotive paints in Danny Lambert OP37 200 forensic science: measurement variability and depth profile

Friday, September 6, 2013 ORAL SESSION 7 Non-invasive Raman Investigation

The Art of non-invasive in situ Raman spectroscopy: Costanza Miliani PL4 203 identification of chromate pigments on Van Gogh paintings

Characterisation of a new mobile Raman spectrometer Debbie Lauwers OP38 205 for in-situ analysis

On-site high-resolution Raman spectroscopy on minerals and pigments Martin A. Ziemann OP39 207

Molecular characterization and technical study of historic aircraft windows and head gear using portable Odile Madden OP40 208 Raman spectroscopy

ROUND TABLE – Raman spectral database

The Infrared and Raman Users Group Web-based Marcello Picollo PL5 210 Raman Spectral Database

RAA 2013 18 Monday, September 2 PL1

Raman Spectroscopy of Extremophilic Biodeterioration: An Interface Between Archaeology and the Preservation of Cultural Heritage

Howell Gwynne M. Edwards1*

1 Centre for Astrobiology and Extremophiles Research, School of Life Sciences, University of Bradford, West Yorkshire, UK, + 44 1274 233787, [email protected]

The identification of biological colonisation in archaeological artefacts and ancient art works represents major problems for the preservation of materials and objects of cultural heritage for conservation scientists and art restorers with the realisation that the deleterious effects of this colonisation can be ongoing even when the artworks have been prepared for storage. The conservation strategies and curation of biodegraded objects from archaeological sites are especially difficult to enforce when the incipient damage has yet to be made evident. Artefacts composed of biological materials are particularly susceptible to biological degradation especially by extremophilic organisms which have developed sophisticated chemical protection strategies for survival in extreme environments which prove to be toxic to other organisms. The application of analytical Raman spectroscopic techniques to the characterisation of the chemical composition of mineral and synthetic paint pigments, ceramics, resins, dyes, textiles and human skeletal remains is also now finding much interest in cultural heritage circles; during these studies it has become apparent that the spectral signatures of biological colonisations that are responsible for the serious deterioration or degradation of archaeological artefacts are closely similar to those which one might expect to find with remote robotic Raman spectroscopic instrumentation on planetary surface and subsurface exploration rover vehicles for the detection of extinct or extant life.

The miniaturisation of Raman spectrometers for the detection of life signatures on planets and their satellites in our Solar System is exemplified by the forthcoming ESA ExoMars mission to the planet Mars which will specifically search for extant or extinct life in the Martian subsurface geological record through a powerful suite of instrumentation that includes a Raman laser spectrometer for the first time. A database of key Raman spectral signatures of species such as carotenoids, chlorophyll, scytonemin and other key protective biochemicals produced by terrestrial specimens of cyanobacterial and lichen extremophiles which exist in stressed hot and cold terrestrial environments such as the Atacama Desert, Arctic meteorite impact craters, volcanic outcrops in Svalbard and the dry Valleys in Antarctica is being complied to identify the presence of biological colonisation in suitable rock matrices. The adaptation of the mineralogy and the host geological matrices by the cyanobacterial colonies and their production of protective biochemicals is a vital requirement for the survival strategy for biological growth and evolution. This is also the case for the biological colonisation of archaeological relics excavated from a depositional environment and a readily available spectral database can hence be assimilated for the identification and characterisation of areas of biological degradation in ancient artefacts which may be used to alert conservators to the urgent need for restorative and preservative strategies to prevent further ongoing specimen deterioration subsequent to superficial cleaning procedures being undertaken.

The potential afforded by the reduction in size and increased portability of Raman spectrometers appeals to conservation scientists for the in situ analytical measurements that can be performed on

RAA 2013 20 PL1 objects without the need for destructive sampling, often in inaccessible locations, and an awareness that the Raman spectral information can reveal the presence of biological agents that could cause the ongoing deterioration of a cultural object need to be recognised. Also, the unsightly growths of cyanobacteria and lichen communities on exposed works of art such as wall paintings, statues and frescoes can be very deleterious and damaging to artistic viewing; in this context, the ability of biological colonies to attach themselves to mineral pigments which are often very hazardous and highly toxic to humans, such as compounds of lead, copper, mercury, antimony and arsenic provides an example of extremophilic behaviour which equally matches the strategies they have adopted to overcome extremes of temperature, pH, radiation insolation and barometric pressure elsewhere terrestrially.

Hence, in this presentation we shall explore some examples of the occurrence of biological colonisation of art works and artefacts in which Raman spectroscopy has provided novel information about the onset of degenerative processes which are often apparent spectroscopically before they are observed visually; this affords the establishment of analytical Raman spectroscopy as an early warning monitor of biological degradation in an artefact which may therefore require urgent conservational treatment to prevent further damage occurring and which will lend support to the apparently unrelated scientific engagement between Raman spectroscopists working on space missions and in the field of cultural heritage preservation.

- The examples used to illustrate this approach will be taken from the following cultural heritage case-studies and scenarios; - Lichen degradation of wall-paintings; - Biological colonisation of badly damaged frescoes undergoing restoration; - Degradation of human mummies from Egyptian Dynastic burials preserved in museum collections; - Biological invasion of grave sites and contributions to the mineral degradation of human skeletal remains; - Definition of biological spectral signatures in archaeological excavations of human and mammoth remains;

The impact of space mission derived data for key biological signatures on the identification of similar signatures from biodegraded artefacts from archaeological excavations will inform future Raman spectrosopic applications for such instruments in archaeological and cultural heritage site work and the identification of biological and associated mineralogical materials which could advise and inform future conservation protocols and approaches.

21 Book of Abstracts OP1

Identification of endolithic survival strategies on stone monuments

Annalaura Casanova Municchia,1* Giulia Caneva,1 Maria Antonietta Ricci,1 Armida Sodo1

1 Department of Sciences, University of Roma Tre, Rome, Italy, +39 06 5757336374, [email protected]

A relevant aspect of stone bio-deterioration is the colonization by endolithic microorganisms that penetrate some millimetres or even centimetres into the rock. This phenomenon is mainly due to a strategy of protection from desiccation and high solar radiation.[1–3] In the literature there are only few studies about the impact of endolithic microorganisms on stone monuments, and on the ecological conditions favouring this kind of colonization. Additionally most studies refer to colonization at extreme environmental conditions, such as cold and hot deserts. Nevertheless, the presence of endolithic microorganisms has been observed in stone monuments in Temperate and Mediterranean climates, especially in comparably dry environments (e.g. vertical surfaces of buildings exposed to sunlight).[4–6] In recent years the study of endolithic organisms in extreme environments has been busted by several astrobiological studies, aimed at finding a trace of life on Mars, where cold deserts, such as Antarctica or the Arctic, have been proposed as the closest analogues to Martian on Earth.[7–9] Consequently, the interest for the development of techniques and protocols for the identification of endolithic microorganisms on stones is spread over a wide scientific field.

We have used Raman spectroscopy to identify rock alteration and pigments traces produced by endolithic microorganisms as survival and adaption strategies to adverse conditions on stones monuments. Notably this technique can easily be implemented (and already is) in space missions. Endolithic cyanobacteria can produce photo protective accessory pigments, such as scytonemin, parietin, calycin; they also mobilize some iron oxides to create a mineral screen layer on the rock surface. In both cases they leave biological or geological traces on rock due to their metabolic activity or indirect effects. We have performed the experiment on different rock samples, in order to investigate the impact of endolithic microorganisms on stone monuments from areas characterized by Temperate and Mediterranean climates. In detail, the aim is to detect key biomarkers and geomarker providing an indicator of different adaptation strategies used in adverse condition and identifying the alterations produced on the substrate.

Figure 1. Microphotographs of cross-section. a.) Sample of Church of Martvili b.) Sample of Hebrew’s cemetery tombstone c.) Sample of cliff of the Amalfi Coast.

RAA 2013 22 OP1

Three different case studies were investigated: Marly limestone samples from the outer wall of Church of the Virgin in Martvili in Georgia that showed a peculiar bio deterioration form, Istrian stone samples from Hebrew’s cemetery tombstone in Venice, and carbonate samples from calcareous cliff of the Amalfi Coast.

In this work we report the observations of cross-section by optical microscope (Figure 1) and scanning electron microscope (SEM) in order to identify the interaction between substrate and microorganisms. Spectra obtained by Raman spectroscopic investigations, carried out in cross-section, were useful to determine the organic and inorganic compounds used by microorganisms as protective mechanisms against stress conditions. The data obtained from the spectra gave rise to identification of molecular bio and geo-marker.

References [1] C. K. Gehrmann, W. E. Krumbein, K. Peterson, International Journal of Mycololgy and Lichenology. 1992, 5, 37–48. [2] O. Salvadori, Characterisation of endolithic communities of stone monuments and natural outcrops. In: O. Ciferri, P. Tiano, G. Mastromei, Of Microbes and Art. The Role of Microbial Communities in the Degradation and Protection of Cultural Heritage. 2000, pp. 89–101. [3] G. Caneva, M. P. Nugari, O. Salvadori, Plant Biology for Cultural Heritage. Biodeterioration and Conservation. The Getty Conservation Institute, Los Angeles, 2009. [4] A. Danin, G. Caneva, International Biodeterioration & Biodegradation. 1990, 26, 397–417. [5] V. Lombardozzi, T. Castrignanò, M. D’Antonio, A. Casanova Municchia, G. Caneva, International Biodeterioration & Biodegradation. 2012, 73, 8–15. [6] C. Ascaso, J. Wierzchos, J. Delgado Rodrigues, L. Aires-Barros, F. M. A. Henriques, A. E. Charola, International Zeirschrift fur Bauinstandsetzen. 1998, 4, 627–640. [7] H. G. M. Edwards, E. M. Newton, D. L. Dickensheets, D. D. Wynn-Williams, Spectrochimica Acta Part A. 2003, 59, 2277–2290. [8] S. E. J. Villar, H. G. M. Edwards, C. S. Cockell, Analyst. 2005, 130, 156–162. [9] S. E. J. Villar, H. G. M. Edwards, Raman spectroscopy in astrobiology. Anal Bioanal Chem. 2006, 384(1), 100–113.

23 Book of Abstracts OP2

FT-Raman analysis of historical cellulosic fibres infected by fungi

Katja Kavkler,1* Andrej Demšar2

1 Restoration Centre, Conservation Centre, Institute for the Protection of Cultural Heritage of Slovenia, Ljubljana, Slovenia, [email protected] 2 Department of Textiles, University of Ljubljana, Faculty of Natural Sciences and Engineering, Ljubljana, Slovenia, [email protected]

Introduction Historical textiles can be degraded by different internal and external factors. Fungi are one of the most severe textiles’ degraders [1], which attack especially pre-degraded materials, since the depolymerisation and changes in inter- as well as intramolecular bonds facilitate access of fungal enzymes to molecules. Textile deterioration has been studied previously with different methods [2,3]. This time we decided to analyse bio-deteriorated as well as non-affected objects by FT-Raman spectroscopy.

Materials and methods Textile samples Historical samples were obtained from 14 different historical textile objects originating from different historical periods since 16th century. The samples were taken off in the form of pieces of fabrics or single threads, from objects, where stains were observed, for which we suspected to be of fungal origin, or where mycelium was observed on the surface of the objects.

FT-Raman The FT-Raman instrument is a Bruker multiRAM with cryo‑cooled Ge detector and a Nd‑YAG laser with a wavelength of 1064 nm with a line width of ~ 5‑10 cm‑1 and a resolution of 4 cm‑1. The software used is OPUS Beta version. The laser intensity has been between 30 and 150 mW. The number of scans has generally been between 100 and 5000. The surface area of analysis is ~ 20 µm in diameter.

Results and discussion Of all the 14 investigated objects, three were made of cotton, two of mixture of flax and hemp and all others of pure flax. Half of the investigated objects were infected by different fungal strains, among them one made of cotton and six made of flax. The infected cotton object was underwear, whereas all other infected objects were painting canvases.

We observed structural properties using FT-Raman spectroscopy, after the dispersive Raman spectroscopy proved to be long lasting and not always reliable method [2]. However, the FT-Raman spectroscopic method caused some problems with luminescent background as well. The spectra of non-infected cotton specimen, spectra of both samples with mixed fibres as well as two spectra of flax had strong background with non-visible or barely visible cellulose bands and their structure could not be interpreted.

To determine structural changes within cellulose fibres we compared spectra from investigated objects with those from contemporary fibres, processed in old fashioned manner, of natural colour and non- sized. Some differences in spectra can be attributed to different growth and processing conditions, but others are sings for different intensive structural changes.

RAA 2013 24 OP2

The inoculated object made of cotton gave spectra with only low background and clear bands. From the spectrum we concluded, that ageing as well as biodeterioration caused decreased crystallinity of cellulose and its degradation [4], as seen from the decrease of the bands at 380 cm-1, 437 cm-1, 1096 cm-1 and 1120 cm-1.

Of the investigated objects made of flax, six were inoculated and four not. In one of the non-inoculated spectra, obtained from the only object made of flax, which was not painting but an embroidered tablecloth, we could observe opposite changes than usually. The increased bands at 457 cm-1, 520 cm-1 and 1120 cm-1 are signs of increased crystallinity or more ordered cellulose structure [4-6].

In spectra of two of the inoculated samples no bands could be observed due to strong background emissions, which is probably the consequence of bio-deterioration [5]. In one spectrum only the strongest bands were visible. Due to deterioration the two bands around 1100 cm-1 joined into a broad band with peak at 1096 cm-1. In three inoculated specimens bands were clearly visible despite the luminescent background, and the structural changes could be investigated. The decreased bands at 995 cm-1 and 1480 cm-1 are a sign of deterioration of cellulose in all three investigated spectra, [7] as well as the decrease of the bands at 1096 cm-1 and 1120 cm-1 [5] in two spectra.

From the results of the FT-Raman analysis of museum objects infected by fungi we can conclude that as does the dispersive Raman, also the FT-Raman can cause difficulties when analysing historical textiles, especially when the fibres are severely deteriorated. However, structural changes can be observed in most of the spectra already after a short acquisition times. In the investigated specimens we observed that not only biodeterioration, but also other ageing factors can cause changes in cellulose structure. As seen from our results, the fungi caused more severe decrease in crystallinity than environmental factors.

The authors would like to thank Ingalill Nystrom and Department for Conservation of the University of Gothenburg, Sweden, for giving the possibility to use the FT-Raman in their institution. We would also like to thank Slovene Museum of Christianity, Ptuj Regional Museum and Department for Easel Paintings of the Restoration Centre of the Institute for the Protection of Cultural Heritage of Slovenia for providing the sampling objects.

References [1] A. Seves, M. Romanò, T. Maifreni, S. Sora, O. Ciferri, International Biodeterioration & Biodegradation. 1998, 42, 203. [2] K. Kavkler, A. Demšar, Spectrochimica Acta. Part A. 2011, 78(2), 740–746. [3] K. Kavkler, N. Gunde-Cimerman, P. Zalar, A. Demšar, Polymer degradation and stability. 2011, 96(4), 574. [4] M. Petrou, H. G. M. Edwards, R. C. Janaway, G. B. Thompson, A. S. Wilson, Analytical and Bioanalytical Chemistry. 2009, 395, 2131. [5] H. G. M. Edwards, J. M. Chalmers, Raman Spectroscopy in Archaeology and Art History, Royal Society of Chemistry: Cambridge, Great Britain, 2006, p. 304. [6] H. G. M. Edwards, N. F. Nikhassan, D. W. Farwell, P. Garside, P. Wyeth, J. of Raman spectrosc. 2006, 37, 1193. [7] H. G. M. Edwards, E. Ellis, D. W. Farwell, R. C. Janaway, J. of Raman Spectrosc. 1996, 27, 663.

25 Book of Abstracts OP3

Combined FT-Raman and Fibre-Optic Reflectance Spectroscopic Characterisation of Simulated Medieval Paint Films: a Chemometric Study of the Effects of Natural and UV-Accelerated Ageing

Anuradha Pallipurath,1 Jonathan Skelton,1* Spike Bucklow, 2 Stephen R. Elliott1

1 Department of Chemistry, University of Cambridge, UK, [email protected] 2 The Hamilton Kerr Institute, Fitzwilliam Museum, Cambridge, UK

Non-invasive methods for analysing artwork are fast gaining interest due to their facilitating non- destructive and in-situ analyses, without the need for sampling. Raman spectroscopy is one such technique, and has been widely used for this purpose. Despite being a weak phenomenon, Raman scattering can give a wealth of information about the chemical functional groups that make up chromophores, as well as the crystal structures of pigment molecules, from their atomic-vibrational spectra. This information can not only be used to characterise the materials in, and hence date, artwork, but can also be used to detect forgeries.

However, during in-situ analyses of artwork, distinguishable Raman scattering from the pigment can often be reduced, or even completely masked, by fluorescence from the glazing materials or organic binders used. While a lot of importance has been given to the study of pigments, identifying the organic binding materials used has never been an easy task. In addition to fluorescing at visible wavelengths, most binders also have characteristic vibrational-spectroscopy peaks in the same spectral regions, e.g. corresponding to C-H and carbonyl stretches, making their differentiation challenging. Previously, we have shown that the use of multiple spectroscopic data sources, e.g. FT-Raman and fibre-optic reflectance spectra, together with multivariate analysis techniques, not only helps to indentify fat- based binders, but also proteinacious and polysaccharide-based binders, such as gum Arabic and egg, which are otherwise difficult to differentiate.[1]

In this work, we have extended these techniques to understand the nature of possible interactions between binders and bound pigments, and to estimate relative concentrations of components in paint films using FT-Raman spectroscopy. We have also studied naturally and artificially (UV) aged samples to understand how these interactions change with time. In addition, we have developed chemometric methods to enable computer-assisted analysis of such spectral data from simulated paint samples, with a view to working towards an automated identification of paint-binder materials from spectroscopic data.

Finally, we have also investigated how several different support materials, viz. glass, canvas and parchment, the latter two of which, like binding media, are organic materials, influence the paint film spectra and hence the results from our analysis techniques.

References [1] A. Pallipurath, J. Skelton, P. Ricciardi, S. Bucklow, S. Elliott, J. of Raman Spectrosc. 2013, 44 (6), 866–874.

RAA 2013 26 OP4

Study of malachite degradation in easel (model) paintings by spectroscopic analysis

Tanja Špec,1* Klara Retko,1 Polonca Ropret,1,2 Janez Bernard3

1 Research Institute, Conservation Centre, Institute for the Protection of the Cultural heritage of Slovenia, +386 1 2343118, (tanja.spec, polona.ropret, klara retko)@rescen.si 2 Museum Conservation Institute, Smithsonian Institution, Suitland, MD, USA 3 Slovenian National Building and Civil Engineering Institute, +386 1 2804204, [email protected]

2+ Malachite, copper(II) carbonate [Cu 2(CO3)(OH)2] is perhaps the oldest green pigment and has been intensively used in different works of art from Antiquity until late 1800. It has often been proved to be permanent in oil and tempera paintings, although sometimes brownish hue may appear due to the oil darkening.[1] The present study describes an interaction between pigment and different binders and an effect of accelerated aging in easel model paintings which were prepared according to the traditional Baroque recipes.[2] Before applied on white gesso ground, colour layers containing malachite, mixed with egg tempera and/or oil medium were prepared. As finishing protective layers, egg white and mastics were added on selected areas of the easel painting. The use of different combinations of binders and varnishes enabled an extended study of different influential factors on pigment degradation. One set of model samples

Figure 1. a.) A Photomicrograph of the polished cross-section and location of spot 2 for Raman analysis. b.) A Photomicrograph of the polished cross section and location of spot 3 for Raman analysis. c) Raman spectra of Malachite (1), Copper oxide (2) and Copper oxalate (3).

27 Book of Abstracts OP4 were exposed to the effects of climate parameters variations, such as temperature, relative humidity and UV-VIS radiation. The other set was left non-aged and it served as the control. Exposure of model easel paintings to environmental parameters in climate chambers was completed after two months. On both model paintings, colorimetric measurements were made in order to determine the differences in colour before and after ageing. Utilizing Micro-Raman spectroscopy, different green areas of each sample’s cross-section were analyzed. Supporting analytical methods, such as SEM (Scanning electron microscopy), FT-IR (Fourier transform infrared spectroscopy) and XRD (X-ray Diffraction) were employed to obtain additional information on the degradation process of malachite colour layers. The Raman bands of malachite were determined on all control samples, where the bands are in a good agreement with literature data.[3] Beside the green particles of malachite, the black particles were also detected in all of the samples. Nevertheless, much higher proportion of the latter was observed in the aged samples. Obtained Raman spectra of those particles indicate the presence of a copper oxide. (Figure 1c, Graph 2).[4] In addition, the scanning electron microscopy (SEM) shows the increased relative amount of copper on dark particles in respect to green ones. Furthermore, where oil medium was used as the binder, Raman spectra offered additional results. Beside copper oxide, strong bands of another compound were recorded at 552, 588, 618 cm-1 (Figure 1b and Figure 1c, Graph 3), which suggests the presence of a copper oxalate.[5] The formation of oxalates on easel paintings is more likely to appear in the presence of biochemical activity of lichens, fungi or bacteria[6], which in our study can be eliminated, due to the known preparation of the model samples and controlled environmental conditions in climatic chambers. However, some of the previous studies concluded that decomposition of organic materials, such as proteins, oil, waxes, etc., can also lead towards the formation of oxalic acid [7], which is most likely the reason for the copper oxalate formation found in the present study. The presence of oxalate was confirmed also by FT-IR spectroscopy.

References [1] A. Roy (Ed.), Artists’ Pigments. A handbook of their History and Characteristics, vol. 2 Oxford University Press: New York, 1993, p. 184. [2] R. Hudoklin, Tehnologije materialov, ki se uporabljajo v slikarstvu, vol. 2, Ljubljana, 1958, p. 121. [3] R. J. H. Clark, P. J. Gibbs, Spectrochim. Acta Part A. 1997, 53, 2159. [4] L. Debibichi, M. C. Marco de Lucas, J. F. Pierson, P. Küger, J. Phys. Chem. 2012, 116, 10232. [5] K. Castro, A. Sarmiento, I. Martinez-Arkarazo, J. M. Madariaga, L. A. Fernandez, Anal. Chem, 2008, 80, 4103. [6] H. G. M Edwards. N. C. Russel, M. R. D Seaward, Spectrochimica Acta Part A. 1999, 53, 99. [7] N. Mendes, C. Lofrumento, A. Migliori, E. M. Castellucci, J. Raman Spectros. 2008, 39, 289.

RAA 2013 28 OP5

Portable and laboratory analysis to diagnose the formation of efflorescence on walls and wall paintings of Insula IX, 3 (Pompeii, Italy)

Juan Manuel Madariaga,1* Maite Maguregui,2 Silvia Fdez-Ortiz de Vallejuelo,1 Africa Pitarch,1 Ulla Knuutinen,3 Kepa Castro,1 Irantzu Martinez-Arkarazo,1 Anastasia Giakoumaki1

1 Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country UPV/EHU, Spain, +34946018298, [email protected] 2 Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country UPV EHU, Spain 3 Department of Art and Culture Studies, University of Jyväskylä, Finland

Since the time that any archaeological site is brought to light, it suffers deterioration due in part to rain- fall, humidity, water infiltrations, etc., but mainly to environmental stressors. Raman spectroscopy and other analytical techniques, both portable and laboratory, are increasingly used to identify the deterioration compounds promoted by the reactivity between stressors (acidic gases, microorganisms, etc.) and original materials that promotes the formation of new compounds (efflorescence or crystallized salts) like bicarbonates, sulphates and nitrates. In the particular case of the Pompeii site, the impacts due to the eruption must be added to the others. The APUV expeditions (2010, 2011 and 2012) were focused on the walls and wall paintings of two houses from Insula IX, 3 (Houses 1,2 and 5,24); some rooms of greater importance are covered with ceilings but the majority of rooms in both houses are exposed to the open air. During the expeditions, the nature of the efflorescence in the walls and wall paintings was evaluated using portable, non-destructive instrumentation. Raman spectroscopy, assisted by diffuse reflectance infrared spectroscopy (DRIFTS) was used to obtain the molecular composition and energy-dispersive X-ray fluorescence (ED-XRF) for the elemental analysis. Some efflorescence samples were also taken to perform laboratory analysis using the same analytical techniques but also DRX and SEM/EDX, as well as some mortar samples, detached from the walls, were taken to perform the soluble salt quantification. Exposed and protected rooms were measured in spring (May 2010) and summer (September 2011 and 2012), considering different orientations and the walls affected (and not affected) in its back by rainfalls to observe possible variations in the salts crystallizations. The spring 2010 was with few rainfalls, and little amount of efflorescence were detected in the walls and practically nothing in the wall paintings of the protected rooms. The end of August 2011 was rainy and the walls in the protected rooms, especially those oriented in its back to the main rainfalls, were completely wet; some efflorescence like crystals were two to five millimeters long. The middle of summer 2012 was also rainy, the walls were not wet when we performed the measurements, but in this case a notable amount of efflorescence crystals were evident even in the wallpaintings of the covered rooms.

The CO2 attack on non-protected walls is the greatest decaying phenomena accompanied by rain wash of the highly soluble metal bicarbonate salts formed after the acid attack (decarbonation of wall paintings and plaster layers till observation of the arriccio mortar). Any bicarbonate salt was measured

in-situ and only calcium, sodium and potassium carbonate (CaCO3, Na2CO3, K2CO3) were identified by Raman spectroscopy. All of them can be considered original compounds in the mortars; the source for potassium was found in the own walls, probably coming from the original mortar manufacturing when using local potassium-bicarbonate type waters.

29 Book of Abstracts OP5

In protected wall paintings and walls (rooms covered by roof) higher sulphur contents were observed (severe sulphation decaying) while a lower amount of sulphur was quantified in exposed walls (partial dissolution of metallic sulphate salts by rain-washing). Apart from gypsum (CaSO4.2H2O), thenardite

(Na2SO4), mirabillite (Na2SO4.10H2O), aphthitalite (K3Na(SO4)2) and syngenite (K2Ca(SO4)2.H2O) were detected in areas far from the presence of modern mortars and cements used un past restoration processes; sulphates with higher water content were observed in protected rooms where the wall was wet (2011 expedition), i.e., those having its back in front of the main wind (and rain falls) and belonging to other rooms without any roofing protection.

Additionally, nitrate salts like lime nitrate (Ca(NO3)2), niter (KNO3) and nitrammite (NH4NO3) were detected only in protected rooms due to its high solubility. Especially in the expedition of 2011, nearly pure Raman spectra of niter were collected with the portable instrument, indicating the high concentration of this nitrate in the analysed efflorescence. But the most surprising result was observed in the 2012 expedition, where niter was in-situ measured in the white efflorescence crystals appearing through the pigmented layers in wall paintings of several rooms, all of them having well setting roofs. Chemical modeling and chemometrics were used to explain the results of quantitative concentrations of ions dissolved from the samples taken to the laboratory. This has resulted in a model that explains the deterioration process in terms of chemical reactivity, taking into account the orientations of the walls as well as the covered and not covered situations of the rooms analysed in Insula IX, 3 of the archaeological city of Pompeii. This model will be presented and discussed.

Acknowledgements This work was financially supported by the projects DEMBUMIES (ref.BIA2011-28148), funded by the Spanish MINECO, and Global Change and Heritage (ref. UFI11-26), funded by the University of the Basque Country (UPV-EHU). The accompanying actions CTQ2010-10810-E (MINECO), AE11-27 (UPV- EHU) and AE12-32 (UPV-EHU) supported the expeditions APUV2010, APUV2011 and APUV2012 respectively.

RAA 2013 30 OP6

Decorated plasterwork in the Alhambra investigated by Raman spectroscopy: field and laboratory comparative study

María José Ayora-Cañada,1* Ana Domínguez-Vidal,1 María José de la Torre López,2 María José Campos Suñol,3 Ramón Rubio Domene4

1 Department of Physical and Analytical Chemistry, University of Jaén, Spain, [email protected], [email protected] 2 Department of Geology, University of Jaén, Linares, Spain, [email protected] 3 OTRI, University of Jaén, Spain, [email protected] 4 Conservation Department, Council of The Alhambra and Generalife, Granada, Spain, [email protected]

This work presents the results of the Raman micro-spectroscopic study of decorated plasterworks, situated on the vaults of the Hall of the Kings in the Lions Palace, at the Alhambra in Granada, Spain. The Alhambra was built and decorated during the Nasrid period in the XIII-XVth centuries and then adapted during the first period of Christian domination (XVIth cent). Throughout its history, it has experienced many transformations, with the most important and generalized restorations taking place in XIXth century. The decorated plasterwork under study are the mocarabes or stalactites vaults of the Hall of the Kings. These are self-supporting domes built up with gypsum. Vertical gypsum prisms applied one over another are joined in multiple different arrays resembling stalactites of a cave. These mocarabes are decorated with a wide range of colors mainly red, blue, green, golden and black. Our study has been initiated with a totally non-invasive investigation on the field using a fiber-optic portable Raman microspectrometer. The works were conducted on scaffolding platforms at a height of ca. 12 m above the ground level coinciding with conservation works. The portable Raman microspectrometer (B&W Tek InnoRam) was equipped with a 785-nm laser and an optical probe head attached to a videomicroscope which was mounted on a tripod motorised in the X–Y–Z axes with remote control.

Good quality Raman spectra were obtained during this survey despite working under non-laboratory conditions (e.g. dust, scaffolding, vibrations, daylight, temperature differences). The main practical problems encountered had been related to lack of space for probe positioning due to the typical stalactite like disposition of the mocarabes and vibrations of the scaffolding.

The best results of the field investigations were obtained from red decorations where cinnabar and minium were clearly identified. The position of cinnabar could indicate that this pigment was originally used by Nasrid artists although it was also used in restorations. On the contrary, minium seems not to correspond to original decorations. In many areas red colors appeared altered due to degradation products some of which were identified in situ (like anglesite and calomel). Furthermore, black decorations showed always the Raman signature of carbon and natural Afghan lapis lazuli was identified in most of the blue decorated motifs. Synthetic ultramarine blue was detected only in one of the vaults revealing a recent restoration. However, we did not succeed in obtaining good spectra from green and pale blue-greenish decorations. This is because the laser power had to be extremely low to prevent photodecomposition due to the strong absorption of the 785 nm laser light by green pigments and the scaffolding vibrations made difficult the use of measurement times longer than

31 Book of Abstracts OP6 a few minutes. These field studies have been complemented with laboratory studies on microsamples. Microsamples were carefully taken with a scalped taking into account the information provided by the in situ measurements. They were studied directly by means of a Renishaw (in Via Reflex) Raman microspectrometer coupled to a Leika microscope. The best compacted samples were selected to prepare thin cross sections by embbeding with epoxy resin. With this approach the stratigraphy of the decorations can be also investigated. In this way, we could confirm our previous hypothesis: in several samples a first pictorial layer of cinnabar applied over the gypsum substrate appeared covered by a second pictorial layer of minium. Furthermore, using a 514 nm laser the pale-blue pigment was identified as azurite. Degradation products like calcium oxalates probably formed through microbial degradation of the organic materials employed as binders. In conclusion, the complementary information provided by field measurements with the portable spectrometer and laboratory measurements especially on thin cross sections has allowed a good understanding of the pigments and other materials employed for the decoration of the plasterwork in this Hall of the Alhambra as well as the several degradation phenomena that are taking place.

Figure 1. Detail of the Raman probe head with the microscope during measure

RAA 2013 32 OP7

Multi-technical approach for the study of French Decorative Arts furniture and luxury objects

Céline Daher,1 Ludovic Bellot-Gurlet,2 Céline Paris,2 Juliette Langlois,1 Yannick Vandenberghe,1 Jean Bleton,3 Anne Forray-Carlier, 4 Anne-Solenn Le Hô1 *

1 Centre de Recherche et de Restauration des Musées de France (C2RMF), Palais du Louvre – Porte des Lions, Paris, France, +33 1 40 20 24 22, [email protected], [email protected] 2 Laboratoire de Dynamique, Interactions et Réactivité (LADIR), UMR7075, UPMC-CNRS, Paris, France 3 Laboratoire d'Études des Techniques et Instruments d'Analyse Moléculaire (LETIAM), IUT d'Orsay, Orsay, France 4 Musée des Arts Décoratifs, Les Arts Décoratifs, Paris, France

During the eighteenth century in Europe, a trend in the furniture field was to imitate the Asian lacquers,[1] known as exceptional for their great aesthetic beauty and gloss (Figure 1), and the delicate and fine ornaments. Four brothers, “les frères Martin” were considered as the most famous painters, gilders and varnishes in Paris, and used to work, followed by their descendents, at the royal court of Louis XV. Their work was dedicated to different types of objects, such as household furniture, small boxes for perfumes or make-up, wooden wall paneling, or even sledges and coaches. Their art of imitating Japa- nese and Chinese lacquers required the development of different painting and varnishing techniques, based on European familiar material, and became famous for its high and fine quality.

The Martin’s particularity was to apply a specific varnish “Vernis Martin” [2] on multilayered painted background, on wooden, papier mâché or metallic artifacts. The composition of the varnishes and paints, the different used materials (resins, pigments, dyes, etc.), and in a larger point of view, the Martin’s painting and varnishing techniques, have not been studied yet. These varnishes, or to a larger extent, European lacquers are complex systems made of a colored background, covered with a number of transparent layers.[3,4] Then, colored or gilded ornaments are applied, representing different characters, flowers, or landscapes. The aim of this project was to improve the varnishing techniques knowledge in the Decorative Arts field during the 18th century to enrich the history of art and techniques, and to have a better conservation strategy of such fancy objects.

Figure 1. Photography of a French imitation of Japanese artwork. Inv57965, Musée des Arts Décoratifs, Paris.

In order to reveal this unfamiliar complex system and the Martin’s specific technique, and to characterize the employed materials, a combination of analytical techniques was set up. Among these techniques, some were non-destructive such as Raman, FT-Raman and infrared in reflectance mode,[5] used to identify the varnish composition and the dyes employed for the painted areas directly on the

33 Book of Abstracts OP7 object, or on micro-samples taken from lacunar areas of the artifacts. Other methods were employed to complete the organic analyses (GC/MS, py-GC/MS) or to characterize the mineral compounds (SEM, micro-diffraction).

The presented results are mainly the vibrational analyses ones, on which specific spectral treatments [6] were applied in order to extract detailed information and a better molecular identification thanks to these vibrational signatures. A synthetic overview of the whole obtained data is given, showing the singularity of these complex European preparations not or poorly studied.

Acknowledgements The authors would like to thanks the different museums which collaborated to this project, giving access to all the studied objects: musée des Arts Décoratifs (Paris), musée du Louvre (Paris), and Le Château de Versailles. This work has been financially supported by the foundation “Sciences du Patri- moine” and Labex “Patrima”.

References [1] A.-S. Le Hô, M. Regert, O. Marescot, O., C. Duhamel, J. Langlois, T. Miyakoshi, C. Genty, M. Sablier, Anal. Chim. Acta. 2012, 710, 9. [2] J. F. Watin, L’art de faire ou d’employer les vernis, ou l’art du vernisseur, Quillau, Paris, 1772. [3] A.-S. Le Hô, E. Ravaud, J. Langlois, A. Mathieu-Daudé, E. Laval, A. Jacquin, I. Chochod, M. Bégué, J. Mertens, M.-L. Deschamps, A. Forray-Carlier, ICOM Committe for Conservation: 16th Triennial Meeting, Lisbon, Portugal,19-23 September, 2011, Preprints, electronic format 2011 (CD-ROM). [4] A. Rizzo, Anal. Bioanal. Chem. 2011, 392, 47. [5] W. Vetter and M. Schreiner, e-Preservation Science. 2011, 8, 10. [6] C. Daher, PhD thesis, Université Pierre et Marie Curie (UPMC), 2012, available online: http://tel.ar- chives-ouvertes.fr/tel-00742851/

RAA 2013 34 P1

Deterioration of lead based pigments on a fresco: a micro-Raman investigation

Ilaria Costantini,1 Antonella Casoli,1 Daniele Pontiroli,2 Danilo Bersani,2 Pier Paolo Lottici 2*

1 Chemistry Department, University of Parma, Italy, +39 0521 905425, [email protected] 2 Physics and Earth Sciences Department, University of Parma, Italy, +39 0521905238, [email protected]

Micro-Raman spectroscopy analyses were carried out on some pictorial fragments taken from a portion of the fresco in the Chapel of St. Stephen, situated in Montani (BZ), Val Venosta, Italy, and painted around 1430. Within this building, especially on the apse and on the vault, an alteration of lead based pigments is clearly visible, as a dark coating. The lead pigment was presumably mainly white lead, used to create highlights and light and dark effects. Samples were taken from altered blackened areas and from areas cleaned according to the traditional method of conversion of white lead, using a solution of acetic acid and hydrogen peroxide in cellulose pulp. The “cleaned” samples appear in their original colors, yellow and green. The samples taken from cleaned areas show characteristic spectra of lead- tin yellow pigments, both type I and type II, identified predominantly from green samples. Goethite, hematite, celadonite green earth, and lapis lazuli have also been found. The Raman spectra have been taken at very low (< 0.1 mW) laser power due to the complex behaviour of lead oxides for photo- thermal effects induced by the laser excitation (here 632.8 nm). [1] The micro-Raman spectra from blackened degraded samples give no evidence of white lead but show always a structured wide band centered at about 515-520 cm-1 which can be attributed to

the presence of plattnerite (PbO2), well known alteration product of lead based pigments, especially in presence of moisture and in strongly alkaline environment. The Raman spectra are nearly insensitive of the laser power and very often show PbO (litharge/ massicot) features of varying intensities. Other features at about Figure 1. Raman spectrum of the black 230 cm-1 and 600 cm-1 cannot be attributed to lead oxide phases, degradation material a.) compared with litharge or massicot (Figure 1). On the other hand, starting from that of plattnerite b.). c.) and d.) are Raman

synthetic plattnerite, lead oxides (red lead Pb3O4, litharge and spectra (massicot and litharge, respectively) massicot) are obtained at increasing laser power (Figure 1). obtained by laser photo-degradation of The nature of the dark degradation material is discussed on the plattnerite. basis of Raman and XRD results and on degradation tests on white lead, with different binders.

References [1] L. Burgio, R. J. H. Clark, S. Firth, Analyst, 2001, 126, 222–227.

35 Book of Abstracts P2

Investigation of colour layers in easel (model) paintings influenced by different ageing process

Klara Retko,1* Tanja Špec,1 Polonca Ropret,2

Investigation of deterioration and material degradation on works of art has a great impact in designing better conservation and preservation procedures. Colour layers stability depends to a great extent on the individual stability of a pigment and binder, and possible pigment-binder interactions. Influential factors such us UV-VIS radiation, pollutants exposure, and humidity and temperature oscillation may also accelerate degradation processes. In this study, changes of physical and chemical properties of different colour layers as a consequence of degradation are presented. For that purpose several easel (model paintings), containing different colour layers were prepared in which all materials selected for the preparation of model samples corresponded to the materials used in the Baroque period.[1] Therefore pigments such as lead white, lead tin yellow (type I), prussian blue, smalt, azurite and vermilion were employed. Each pigment was mixed with egg tempera or oil medium and applied on a gesso ground. Model samples were then exposed to artificial accelerated ageing process for a period of two months, using well-controlled climatic chambers. One set of model easel paintings was exposed in the climatic chamber where oscillations of temperature and relative humidity were performed, while the other set of samples was exposed to the UV-VIS radiation. The last set of model samples was left non-aged and served as control.

Figure 1. Raman spectra of non-aged azurite colour layer (AZ_ B2_REF) and azurite colour layers after T,RH (AZ_B2_T,RH) and UV-VIS exposure (AZ_B2_UV-VIS). In all presented samples, linseed oil (B2) was selected as the binder.

Utilizing Micro-Raman spectroscopy all colour layers were examined. The main differences in Raman spectra of aged and non-aged samples that indicate possible degradation process were observed in azurite and lead white containing colour layers. After completed accelerated aging process of blue azurite colour layers, greenish hue has

been observed. According to literature data, conversion of blue pigment azurite (Cu3(CO3)2(OH)2) to the [2] green pigment malachite (Cu2(CO3)2(OH)2) is possible, although mechanism is not well understood. The Raman bands at ~ 153, 180, 220, 269, 354, 432, 1055, 1091 and 1491 cm-1 revealed the presence of malachite[3] (Figure 1), interestingly, only in colour layers prepared in oil medium, and after both exposures (UV-VIS and T, RH). It is possible that the presence of malachite stems from azurite conver-

RAA 2013 36 P2 sion, which appears to be less stable in the medium with higher amount of fatty acids. In cases, when azurite was mixed with lead tin yellow and lead white, it showed a lower stability in the egg tempera after exposed to UV-VIS radiation. To acquire additional knowledge on mechanism of reactions further research is necessary. In lead white colour layers, which were prepared with both binders and exposed to UV-VIS radiation changes in Raman spectra were observed The additional band at 967cm-1 (Figure 2) can be assigned to 2- [4] ν(SO4 ). It is possible that the lead white interacted with a sulphate containing compound.

While the easel painting have not been exposed to air pollutants, such as SOx, which could initiate the formation of sulphates, the source of sulphates is possibly contributed to gypsum (CaSO4·2H2O), present in the ground layer. Interestingly, the effect was observed only after UV-VIS exposure and not under humid conditions. However, additional research needs to be carried out.

Figure 2. Raman spectra of non aged lead white colour layers prepared with egg yolk (LW_B1_REF) and linseed oil (LW_B2_REF) and after UV-VIS exposure (LW_B1_UV-VIS, LW_B2_UV-VIS).

References [1] R. Hudoklin, Tehnologije materialov, ki se uporabljajo v slikarstvu, vol. 2. Ljubljana, 1958, p. 121. [2] A. Lluveras, S. Boularand, A. Andreotti, M. Vendrell-Saz, Applied Physics A. 2010, 99, 363. [3] R. J. H. Clark, P. J. Gibbs, Spectrochimica Acta Part A. 1997, 53, 2159. [4] E. Kotulanová , P. Bezdička, D. Hradil, J. Hradilová, S. Švarcová, T. Grygar, J. Cult. Her. 2009. 10, 367.

37 Book of Abstracts P3

Identification of copper azelate in 19th century Portuguese oil paintings: Characterisation of metal soaps by Raman Spectroscopy

Vanessa Otero,1,2 Diogo Sanches,1, 2 Cristina Montagner,1, 2 Márcia Vilarigues,1, 3 Leslie Carlyle,1, 2 Maria J. Melo1, 2*

1 Departamento de Conservação e Restauro, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Portugal, [email protected] 2 REQUIMTE-CQFB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Portugal 3 VICARTE, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Portugal

Several 19th century oil paintings by the artist Tomás da Anunciação (1821-1879) who is considered a prominent figure of Portuguese romanticism were studied. The identification of the green pigment used in the trees and foliage was not straightforward. The presence of copper in cross-sections was confirmed by micro-Energy Dispersive X-ray Fluorescence (µ-EDXRF) and Scanning Electron Micros- copy coupled with an Energy Dispersive X-ray Spectrometer (SEM-EDS). The green particles were then characterised by micro-Fourier Transform Infrared Spectroscopy (µ-FTIR) and Raman Microscopy (µ-Raman). The infrared fingerprint does not match a copper resinate, but it was possible to detect a band at 1586 cm-1 attributed to the asymmetric COO- stretching of copper carboxylates [1,2]. The detection of these compounds was also confirmed by µ-Raman through the identification of bands at 1440 -1 -1 cm and 1296 cm assigned to CH2 bending. This indicates a reaction between the copper pigment with the surrounding oil binding media [2,3].

Based on these findings, it was decided to test a new set of metal soaps synthesised in the laboratory. The synthesis method was adapted from Robinet and Mazzeo [1, 4]. Metal salts of lead, zinc, calcium, cadmium, copper and manganeseII were used and the carboxylic acids chosen were palmitic, stearic, azelaic and oleic acids. Characterisation was performed by µ-FTIR, µ-Raman and X-ray Diffraction (XRD) and it is anticipated that these results will be of great value for in situ detection of metal soaps by µ-Raman.

The distinction between the saturated carboxylates, copper palmitate and stearate, is not straightforward. The application of a chemometrics approach based on µ-Raman data, for the discrimination of the type of carboxylate, was tested and will be discussed. In contrast, copper azelate and oleate show distinct spectra by µ-Raman as well as by µ-FTIR. Copper azelate shows a dif-

ferent Raman CH2 bending profile and different characteristic bands for C-C stretching and bending. As may be seen in figure 2, the green degradation product detected on Tomás da Anunciação oil paintings matches the copper azelate µ-Raman spectrum. Its identification was also confirmed by Figure 1. Oil painting on canvas entitled Paisagem µ-FTIR on a very small green micro-sample, free from lead e Animais (1851) from Tomás da Anunciação. white. It was possible to identify both the asymmetric and symmetric COO- stretching of copper azelate at 1586 cm-1 and

RAA 2013 38 P3

1417 cm-1, respectively.

Acknowledgements This work has been financially supported by national funds through FCT- Fundação para a Ciência e a Tecnologia under the project PTDC/EAT-EAT/113612/2009. We also thank FCT-MCTES for Vanessa Otero’s PhD grant SFRH/BD/74574/2010, Cristina Montagner’s PhD grant SFRH/BD/66488/2009 and Diogo Sanches’s PhD grant, SFRH / BD / 65690 / 2009. We would also like to thank the curator of The Museu Nacional de Arte Contemporânea – Museu do Chiado, Maria de Aires, for her collaboration.

Figure 2. Raman spectra of a.) green area of a cross-section taken from Paisagem e Animais oil painting of Tomás da Anunciação, b.) copper azelate and c.) copper palmitate.

References [1] L. Robinet, M. Corbeil, Sudies in Conservation. 2003, 48, 23–40. [2] M. Gunn, G. Chottard, E. Rivière, J. Girerd, J. Chottard, J. Studies in Conservation. 2002, 47, 12–23. [3] J. J. Boon, F. Hoogland, K. Keune, AIC paintings specialty group postprints: papers presented at the 34th annual meeting of the AIC of Historic & Artistic Works providence, Rhode Island, 16–19 June, 2006. AIC: H. M. Parkin, Washington, 2007, pp. 16–23. [4] R. Mazzeo, S. Prati, M. Quaranta, E. Joseph, E. Kendix, M. Galeotti, Anal. Bional. Chem. 2008, 392, 65– 76.

39 Book of Abstracts P4

Raman study of pigment degradation due to acetic acid vapours

Alessia Coccato,1* Nathalie De Laet,2 Sylvia Lycke,1,2 Jolien Van Pevenage,2 Luc Moens,2 Peter Vandenabeele1

1 Department of Archaeology, Ghent University, Belgium, [email protected], [email protected] 2 Department of Analytical Chemistry, Ghent University, Belgium

The conservation of works of art that consist of different materials is complicated as the component materials are not equally sensitive to the same environmental conditions. Humidity, light exposure and temperature are known to be dangerous to cultural heritage objects, favouring their degradation through physical, chemical and biological processes. These factors can be easily controlled, especially when the work of art is placed at display in a museum, with limited air circulation, controlled humidity, and temperature. Nevertheless, display cases with wooden parts may cause further damage to their content, because of the release of acetic and formic acid.[1] This evidence has been highlighted by many studies,[2-4] and proved to be itself sensitive to humidity and temperature conditions. For conservative purposes, it is necessary to study also the contribution of acid organic pollutants to the degradation of the materials present in a work of art. Studies are currently performed on pigments, varnishes, leather, parchment, paper and textiles, in the frame of the European FP-7 project MEMORI. Our research is focused on pigment degradation and on the development of a passive air sampler coupled to a dosimeter reader, which is the MEMORI-dosimeter, to monitor the combined effects of all the conditions to which the art object is exposed (climate, organic and inorganic vapours).

The pigment selected for this study are malachite (Cu2(CO3)(OH)2), lead white (Pb2(CO3)(OH)2), red lead

(Pb3O4), lead-tin yellow type I (Pb2SnO4) and pigment orange 36 (C17H13ClN6O5). Different acetic acid atmospheres were produced to simulate the release of organic pollutants from wood in closed cases. Five samples of each pigment were kept in the closed vessels and monitored over 5 weeks. The evaluation of the effects of acetic acid were checked both as a change in colour, and with Raman spectroscopy. Samples were analysed with a Kaiser Hololab 500R spectrometer (λ=785 nm) or a Bruker Senterra spectrometer (λ=532 nm). To take sample inhomogeneity into account, 100 spectra were recorded for each sample, and the results were averaged. Here we present some results for lead- tin yellow (type I). The spectrum of the original pigment is in good agreement with literature (top spectra in Figure 1 and Figure 2) is in good agreement with literature,[5] while it is possible to notice the appearance of new bands (652, 924, 1337, 1422, 2940 cm-1) and sometimes the decrease in intensity of some bands (452 cm-1) in relation with increasing dose (time x concentration), as can be seen in Figure 1. No shifts in the band positions were noticed. The newly formed bands can be ascribed to the formation of acetate salts of lead (II). It seems that acetic acid does not affect the ν(Sn-O) vibration at 194 cm-1, while the ν(Pb-O) stretching band at 452 cm-1 decreases in intensity, suggesting the formation of lead acetate and tin dioxide. The white colour of lead acetate is responsible for the lightening of the yellow tint. The studied pigments showed a different sensitivity towards the aggressive acetic acid atmosphere, some of them being reactive but showing no change in colour (lead acetate is white, as well as basic lead carbonate[6]), some showing strong colour changes (lead-tin yellow type I becomes paler,[7] malachite turns to a bluish-green shade because of the formation of verdigris,[7] red lead darkens probably in relation to the formation of the black lead(IV) oxide plattnerite [8]), finally pigment orange 36 showed no changes in colour nor in the vibrational spectrum. Raman spectroscopy demonstrated once more its effectiveness in the characterization of pigments and their degradation products, in this case in combination with digital photography and RGB measurements.

RAA 2013 40 P4

Acknowledgements The authors wish to acknowledge the MEMORI project for their financial support and for the interesting discussions with the colleagues. The MEMORI, ‘Measurement, Effect Assessment and Mitigation of Pollutant Impact on Movable Cultural Assets. Innovative Research for Market Transfer‘, project is supported through the 7 Framework Programme of the European Commission (http://www. memori‑project.eu/memori.html).

Figure 1. Left: Effect of time on lead tin yellow type I exposed to 33% acetic acid vapours. From top to bottom: pure pigment, after one, three and five weeks of exposure. Right: Effect of increasing concentration of acetic acid on lead tin yellow type I, after four weeks of exposure. From top to bottom: pure pigment, 9%, 20% and 33% acetic acid atmosphere

References [1] W. Hopwood, T. Padfield, D. Erhardt, Science and Technology in the Service of Conservation. 1982, 24– 27. [2] T. Baird, N. H. Tennent, Studies in Conservation. 1985, 30, 73–85. [3] C. Laine, Structures of Hemicelluloses and Pectins in Wood and Pulp. University of Technology: Helsinki, Espoo, Finland, 2005. [4] L. T. Gibson, Corrosion Science. 2010, 52, 172–178. [5] I. M. Bell, R. J. H. Clark, P. J. Gibbs, Spectrochimica Acta Part A. 1997, 53(12), 2159–2179. [6] J. E. Svensson, A. Niklasson, L.G. Johansson, Corrosion Science. 2008, 50, 3031–3037. [7] G. Calvarin, N. Q. Dao, J. P. Vigouroux, E. Husson, Spectrochimica Acta Part A. 1982, 38, 393–398. [8] D. A. Scott, T. D. Chaplin, R. J. H. Clark, J. of Raman Spectroscopy. 2006, 37, 223–229. [9] L. Burgio, R. J. H. Clark, S. Firth. The Analyst. 2001, 126, 222–227.

41 Book of Abstracts P5

Investigating the sources of degradation in corroded lead sculptures from Oratory Museum (Museu do Oratório), Brazil

Thiago Sevilhano Puglieri,1 Dalva Lúcia Araújo de Faria,1* Luiz Antônio Cruz Souza2

1 Instituto de Química, Universidade de São Paulo, Brazil, +55 11 30913853, [email protected] 2 Lacicor – Laboratório de Ciência da Conservação – Escola de Belas Artes, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil

The presence of acetic and formic acids and formaldehyde, combined with inadequate environmental conditions, as high relative humidity (RH) and temperature, constitute a very threatening scenario for the integrity of materials such as metals [1-3]. Wood is a common source of such volatile organic compounds and its use in showcases should be avoided. However, Pb sculptures from Oratory Museum (Museu do Oratório) at Ouro Preto, in the Brazilian state of Minas Gerais, exposed inside glass showcases presented an increasing degradation (Figure 1) and the corrosion sources were to be identified to stop further damage.

Small fragments of the corrosion products, a whitish hair-like material, were collected and analyzed by Raman microscopy, stereomicroscopy, SEM-EDX, FTIR and XRD. Raman spectroscopy was also used to test possible sources of pollutants.

Stereomicroscopy confirmed the formation of crystals, excluding the possibility of afungi attach, while SEM-EDX also revealed the presence of Pb, C and O. XRD detected basic lead carbonate and Raman microscopy showed the formation of Pb carbonates and formates (Figure 2).

The glass showcases were mounted on a painted steel baseplate and, thus, the considered formate sources were the paint used and glass cleaning products. Formaldehyde was widely used as preservative in house-keeping products and, although in Brazil this practice is prohibited since 2008, its use in

Figure 1. Corroded polychrome lead Figure 2. Raman spectra (632.8 nm) from different sculptures of Museu do Oratório. areas of samples collected from the analyzed polychrome lead sculpture.

RAA 2013 42 P5

informal market products is common. An investigation was then carried out on the effects of the paint and glass cleaning products used in the Museum on Pb coupons under controlled conditions (100% RH and 23 ± 2 ˚C). When Pb coupons were exposed to environments containing the fresh paint at 100% RH only carbonates were detected in the corrosion layer, while the coupons exposed together with the cured paint showed the presence of carbonates and formates. Only carbonates were found on the Pb coupons when commercial glass cleaning products were tested (Veja Vidrex® and Cif®) but with a street marketed cleaning product, formates were produced on the metal surface. The results here reported highlight the importance of a careful evaluation of commercial products, particularly cleaning products and paints, aimed to be used inside museums or other institutions that keep artworks or cultural heritage items, considering the potential risk of harmful volatile compounds release that can cause significant damage in the artworks and objects in general.

References [1] A. Niklasson, L. G. Johansson, J. E. Svensson, Journal of the Electrochemical Society. 2007, 154, C618. [2] J. Tetreault, E. Cano, B. M. Van, D. Scott, M. Dennis, M. G. Barthes-Labrousse, L. Minel, L. Robbiola, Stud- ies in Conservation. 2003, 48, 237. [3] D. L. A. de Faria, A. Cavicchioli, T. S. Puglieri, Vibrational Spectroscopy. 2010, 54, 159.

43 Book of Abstracts P6

Evora Cathedral: Pink! Why not?

Tânia Rosado,1 Andreia Reis,1 António Candeias,1 José Mirão,2 Peter Vandenabeele,3 Ana Teresa Caldeira1*

1 HERCULES Laboratory and Evora Chemistry Centre, Évora University, Portugal, +351 266745300, [email protected], [email protected], [email protected] 2 HERCULES Laboratory and Evora Geophysics Centre, Évora University, Portugal, +351 266745300, [email protected] 3 Gent University, Department of Archaeology, Gent, Belgium, +09 264 47 17, [email protected]

Evora Cathedral or Santa Maria Church is one of the most emblematic monuments in Evora, a Southern Portugal monumental town classified by UNESCO as World Heritage. This monument is the biggest Portuguese Cathedral and has a Romanic-Gothic style, or Gothic with Cistercian and Medicant influences. Its construction dates back to the 13th century and was inspired in the model of Lisbon’s Cathedral and other foreign cathedrals. This monument has suffered several conservation and restoration interventions through the ages, without, however, any type of previous knowledge about the type of mortars and materials used. Recent works [1,2] focused on the material characterization of the renders, have shown that the inner walls of the Cathedral are composed of dolomitic aerial lime mortars with siliceous aggregates similar in composition to the granodiorites of Evora’s region with crushed ceramics as additives which can be dated back to a 16th century documented rehabilitation intervention. These works, however, were unable to detect any pigment and hence to explain the pink colour that covers the majority of the inner walls surface. The present work reports our search to explain the pink colour of Evora Cathedral inner walls. An integrated approach was envisaged to explore the anthropic or natural sources of the walls pink colour by combining the material characterization of the surface layers with its microbiological study. Several micro-samples of the surface layer were collected with a small chisel for material characterization by scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDS), micro-Raman spectrometry and micro X-ray diffraction. For the microbiological assays, samples were aseptically collected in pink areas of the walls, followed inoculation in selective media for microorganisms development. The identification of the microbial isolates was performed based on the macroscopic and microscopic features. Microfragments of mortars were further analised by SEM-EDS and micro-Raman spectrometry[3–5] to understand the proliferation of the microorganisms and to characterise the chromatic and microstructural alterations observed in the walls. As expected, the material characterization showed no presence of inorganic chromophores and therefore the use of pigments in the mortars. The microbiological study, however, allowed the identification of several bacterial strains (eg Gram+ cocci/bacilli), 3 yeast strains in particular one of the genera Rhodotorula and filamentous fungi, 5 strains of the genera Penicillium, one strain of the genera Cladosporium, mycelium and sterile micelia were also isolated.

Particularly relevant was the fact that, the predominant isolated microrganism colonies, Rhodotorula sp yeast, exhibited a strong pink / dark orange colour that was further investigated to establish the

RAA 2013 44 P6 effect of its growth on the mortars by different sets of experiments: - Innoculation of Rhodotorula sp yeast on mortar test specimens for microorganisms proliferation evaluation, - Insertion of original historical mortar on sterilized liquid culture media under controlled conditions for detection of metabolic compounds, - Liquid cultures of isolated Rhodotorula sp yeast for production of metabolic compounds.

A) C)

Figure 1. a.) Detail of the inner wall of the Évora Cathedral with the SEM micrograph of the mortar with the yeast b.) Isolated yeast culture c.) Raman spectrum of mortar microsample biological contaminated with carotenoids peaks evidenced (carbon-carbon single-bond stretch vibration (1159 cm−1) and carbon- carbon double-bond stretch vibration (1525 cm−1) of the molecule’s backbone).

The envisaged spectroscopic approach on historical and test specimens, and particularly the micro- Raman spectrometry, allowed evaluating the micro flora proliferation, the presence of oxalates in the mortars, due to the metabolic activity of the microorganisms and carotenoids detection that can be attributed to the development of the Rhodotorula sp yeast. Therefore, the perceived pink color of the Cathedral is due to nature’s process rather than to Human intention.

Acknowledgements This work has been financially supported by the Portuguese Science and Technology Foundation (FCT) through SFRH/BD/65747/2009 PhD grant and contract PEst-OE/QUI/UI0619/2011.

References [1] A. S. Silva, P. Adriano, A. Magalhães, J. Pires, A. Carvalho, A. J. Cruz, J. Mirão, A. Candeias, Int. J. Arch. Heritage, 2010, 4, 1. [2] P. Adriano, A. Santos Silva, R. Veiga, J. Mirão, A. E. Candeias, Materials Characterization, 2009, 60, 610. [3] J. R. Goodwin, L. M. Hafner, P. M. Fredericks, J. Raman Spectrosc. 2006, 37, 932. [4] S. E. J. Villar, H. G. M. Edwards, M. R. D. Seaward, Spectrochimica Acta Part A. 2004, 60, 1229. [5] H. G. M. Edwards, E. M. Newton, J. Russ, J. Molec. Struct. 2000, 245, 550.

45 Book of Abstracts P7

Study of red biopatina composition on sandstone from a historical War Fort in La Galea (Biscay, north of Spain) by means of single point focusing Raman analysis and Raman Imaging combined with microscopic observations

Héctor Morillas,1 Maite Maguregui,2 Josu Trebolazabala,1 Isabel Salcedo,3 Juan Manuel Madariaga1*

1 Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country UPV/EHU, Bilbao, Basque Country, Spain, +349 46018298, [email protected] 2 Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country UPV/ EHU, Vitoria-Gasteiz, Basque Country, Spain 3 Department of Vegetable Biology and Ecology, Faculty of Science and Technology, University of the Basque Country UPV/EHU, Bilbao, Basque Country, Spain

For many years, historical buildings have suffered the aesthetical and structural changes caused by cyanobacteria, algae, etc. colonization. Among building materials used in historical buildings sandstone is one of the most used materials together with stone, bricks and mortars. This material can suffer biological colonization and consequently colored biofilms can be formed on its surface, giving as a result the pathology called biodeterioration. In the literature many authors pointed out that the biodeterioration process can promote physical and mechanical stress, chemical changes in the composition of porous building materials, etc. To understand this deterioration process it is important to study the composition of the newly formed biopatina. In this work, the characterization of the nature of main carotenoids and their distribution on red biopatinas formed over the sandstones that constitute the tower in the Fort of Galea, located in Getxo (Basque Country, North of Spain) was carried out. For that purpose, single point focusing Raman analysis and Raman imaging was carried out. This spectroscopic technique was also useful to perform the mineralogical characterization of the sandstone. In order to obtain preliminary results, a portable Raman instrument was also moved to the place where the fort is located, in order to obtain on site Raman spectra of the colonized areas. In the laboratory, and additionally to the Raman analysis, the nature of the main colonizer of the sandstone in the Fort of Galea (see Figure 1-A) was approached using scanning electron microscopy and phase contrast microscopy. On site analysis performed over red biopatinas (see Figure 1-B) with the portable Raman instrument showed the main bands of carotenoids (1526, 1158 and 1006 cm-1). This observation indicate that the main colonizer of the sandstone is able to excrete carotenoids or it is an organic pigment constituent of its structure. Raman analysis performed on the laboratory showed that the main components of the sandstone, which acts as the support for the colonization, are quartz, iron (III) oxides or oxihydroxides such as hematite, limonite and lepidocrocite, aluminosilicates such as adularia, ortoclasa, carbon etc. In order to extract more information about the nature of the main colonizer, samples were observed under phase contrast optical microscopy and scanning electron microscopy (see Figure 1-C and D). According to the SEM and optical microphotographs, it can be concluded that an algae is the main colonizer of the red biopatina that belongs to a genus of filamentous green chlorophyte algae, specifically in the family of Trentepohliaceae. Trentepohlia algae can provide a very efficient biological system for harvesting solar energy for the production of organic compounds through the photosynthetic process. Concretely, the identification

RAA 2013 46 P7 of β-carotene crystals (see Figure 1-C, D and E) in the pigment globules suggests that the algae have developed a defense system against photooxidative and oxidative damages. Apart from β-carotene, scytonemin (see Figure 1-F) was also identified in some areas of the red biopatina. This yellow-brown pigment is usually present in the extracellular sheaths of cyanobacteria. The presence of this organic pigment could suggest a combined presence of Trentepohlia and cyanobacteria. To understand better the distribution of β-carotene and scytonemin over the Trentepohlia, Raman imaging on β-carotene crystals and scytonemin was carried out.

Figure 1. a.) The Tower of Fort of Galea. b.) A detail of the red colonization on the sandstone of the fort. c.) Microphotography obtained with the phase contrast microscope showing Trentepohlia alga and its β-carotene crystals in the pigment globules. d.) SEM microphography showing β-carotene crystal. e.) Raman spectrum of β-carotene and f.) Raman spectrum of Scytonemin.

Acknowledgements This work was financially supported by DEMBUMIES (ref.BIA2011-28148) funded by (MINECO). H.Morillas is grateful to the University of the Basque Country (UPV-EHU) and mainly to the action UFI 11-26 Global Change and Heritage, who funded his pre-doctoral fellowship.

47 Book of Abstracts P8

Raman and non invasive IR analyses of natural organic coatings: application to historical violin varnishes

Céline Daher,1,3* Ludovic Bellot-Gurlet,1 Stéphane Vaiedelich,2 Jean-Philippe Echard2

1 Laboratoire de Dynamique, Interactions et Réactivité (LADIR), UMR7075, UPMC-CNRS, Paris, France 2 Laboratoire de Recherche et de Restauration, Musée de la Musique, Cité de la Musique, Paris, France 3 Centre de Rechercheet de Restauration des Musées de France (C2RMF), Palais du Louvre, Paris, France, +33 1 40 20 24 22, [email protected]

During the eighteenth century in Europe, musical instruments’ varnishes have been essentially made with an oil base (linseed oil, in most cases) to which terpenic resins have been added, such as colophony, Venice turpentine, mastic, etc [1]. Moreover, these varnishes were sometimes slightly pigmented for a light red color. The most used approaches determining the composition of ancient varnishes were based on destructive analyses of micro samples, mainly gas chromatography methods coupled to mass spectrometry.[2,3] Other analytical approaches, non-destructive and even non-invasive ones, have been investigated. Indeed, previous studies [4–6] show that Raman and Infrared spectroscopies can identify and discriminate between natural organic media. The pigments inclusions can also be identify using vibrational spectroscopies whether for mineral pigments or organic ones.

A first aspect of this study is to characterize historical varnishes by using a totally non-invasive technique, IR spectroscopy in a specular reflection mode for the varnish analyses.[7] However, using this unusual mode can present difficulties for the spectra interpretation; the bands have often a derivative shape,[8] and no databases of such spectra are available yet. In order to get a better understanding of the obtained spectra and to be able to characterize the vibrational features, the Kramers Kronig transformation (KKT) has to be applied. In order to validate this new approach, model experimental varnishes were analyzed both in specular reflection mode then KKT-corrected, and in conventional absorbance mode, showing that the spectral features were similar.

The studied stringed instruments, kept in the Musée de la Musique in Paris, are from the 18th and early 19th centuries and from different European violin makers: Antonio Stradivari and Giuseppe Guarneri ‘del Gesù’ (Italy), Gabriel Buchstetter and Leopold Widhalm (Germany) and Nicolas Lupot (France). In situ IR spectroscopy in reflectance mode appeared to be the most suitable non-invasive and non- destructive technique to date to allow the characterization of their organic coatings. The presented results show the influence of the instrument’s surface aspect (conservation state) on the reflectance spectra: The more smooth and reflective the object surface is, the better is the signal, which is however difficult to meet on ancient objects. Nevertheless, it has been possible to positively characterize the nature of the upper varnish layer, but also the chemical nature of the underlayer, visible on lacunar or erosion areas.

The second aspect is to characterize the colored red grains by Raman spectroscopy. Tests by portable 785 nm Raman were unfortunately not successful; the fluorescence of the varnish hampered the Raman signal. Therefore, micro-samples were taken from three instruments by A. Stradivary were analyzed using a bench top instrument working at 458 nm [9]. The red particles appeared to be a mix between an anthraquinonic organic pigment (possibly carminic acid) and inorganic iron oxide (hematite).This

RAA 2013 48 P8 study is a first example of non-invasive analyses of natural organic compounds using IR spectroscopy. Moreover, post treatments could be applied on the resulting spectra such as spectral decomposition, in order to get more detailed information of the varnish composition, for instance the different compounds present in mixtures. On the other hand, we attested the presence of a fine dispersion of various pigments by Raman spectroscopy, documenting the varnishes coloring techniques. Finally, the next step of this study would be to try in situ Raman analyses under a micro-spectrometer of the varnish instrument knowing that the difficulty is actually the moving of these prestigious historical instruments out of the museum.

References [1] J.-P. Echard and B. Lavedrine, J. Cult. Herit. 2008, 9, 420. [2] J.-P. Echard, C. Benoit, J. Peris-Vicente, V. Malecki, J. V. Gimeno-Adelanto, S. Vaiedelich, Anal. Chim. Acta. 2007, 584, 172. [3] G. Chiavari, S. Montalbani and V. Otero, Rapid Commun. Mass Sp. 2008, 22, 3711. [4] P. Vandenabeele, B. Wheling, L. Moens, H. Edwards, M. De Reu, G. Van Hooydonk, Anal. Chim. Acta 2001, 407, 261. [5] C. Daher, C. Paris, A.-S. Le Hô, L. Bellot-Gurlet, J.-P. Echard, J. Raman Spectrosc. 2010, 41, 1204. [6] L. Bertrand, L. Robinet, S. X. Cohen, C. Sandt, A.-S. Le Hô, B. Soulier, A. Lattuati-Derieux and J.-P. Echard, Anal. Bioanal. Chem. 2011, 399, 3025. [7] W. Vetter and M. Schreiner, e-Preservation Science. 2011, 8, 10. [8] C. Miliani, F. Rosi, A. Daveri, B. G. Brunetti, Applied Physics A. 2012, 106, 295. [9] J.-P. Echard, L. Bertrand, A. von Bohlen, A.-S. Le Hô, C. Paris, L. Bellot-Gurlet, B. Soulier, A. Lattuati- Derieux, S. Thao, L. Robinet, B. Lavédrine, S. Vaiedelich, Angew. Chem. Int. Edit., 2010, 49, 197.

49 Book of Abstracts P10

Optical Microscopy and Micro-Raman studies of The Hans Memling’s Triptych “The Last Judgment

Ewa Pięta,1* Justyna Olszewska-Świetlik,2 Edyta Proniewicz3

1 Faculty of Chemistry, Jagiellonian University, Kraków, Poland, +48 12 663 22 55, [email protected] 2 Department of Painting Technologies and Techniques, The Institute for the Study, Restoration and Conservation of Cultural Heritage, Nicolaus Copernicus University in Toruń, Poland, +48 056 611 38 22, [email protected] 3 Faculty of Chemistry, Jagiellonian University, Kraków, Poland, +48 012-663 2077, [email protected]

The general aim of this work, that combines chemical and historical knowledge, was Optical Microscopy and Raman analysis of four multilayered samples taken from four different painting’s parts (three from the central panel and one from the right wing) of the Hans Memling’s Triptych “The Last Judgment” (Figure 1). “The Last Judgment” (1467–1471) by Hans Memling is one of the most precious works of Polish art collections. This outstanding masterpiece belongs to the collection of National Museum in Gdańsk and has been classified as the netherlandish painting.

The Raman spectra of the painting’s cross-sections taken from these samples possess a unique set of bands corresponding to the individual layers [1]. Therefore, these spectra allowed us to determine the chemical composition of each layer in the cross- section of samples. The following pigments were detected: lead white, lead tin yellow type I, cinnabar, red ochre, and carbon black. In all of the cases chalk was used as a ground layer. These results are precious source of information about main features of school of painting presented by Hans Memling. Additionally, our results allow art historians to characterize the influence of different Figure 1. Hans Memling, “The Last cultures on the Memling’s artistic work and to plan conservation, Judgment”, Netherlands school, National restoration, and preservation procedures of his paintings. Museum in Gdańsk (photo A. Skowroński).

References

[1] E. Pięta, E. Proniewicz, J. Olszewska-Świetlik, Raman spectroscopy for the identification of pigments, dyes, and binding media from the Hans Memling Triptych The Last Judgment, in: On the border of Chemistry and Biology, vol. 29, UAM Press: Poznań, 2012, p. 343.

RAA 2013 50 P9

Characterization of green copper organometallic pigments and understanding of their degradation process in European easel paintings

Carlotta Santoro,1,2* Anne-Solenn Le Hô,2 Sigrid Mirabaud,3 François Mirambet,2 Sandrine Pagès-Camagna,2 Pascal Griesmar, 4 Nadège Lubin-Germain,1 Michel Menu2

1 Le laboratoire de Synthèse Organique Sélective et de Chimie bioOrganique (SOSCO, EA 4505), CNRS, Université de Cergy-Pontoise, France, +33134257384, [email protected] 2 Centre de Recherche et Restauration des Musées de France (C2RMF), Paris, France 3 Institut National du Patrimoine (INP), France 4 Laboratoire Système de l’Application des Technologies de l’Information et de l’Energie (SATIE), UMR 8029 CNRS, ENS, Université de Cergy-Pontoise, France

Verdigris and copper resinate are organometallic complexes of Cu(II). They were widely use as pigments in XVth and XVIth centuries for their transparency in glazes. These compounds are often subject to changes with time. There are numerous cases of ageing and darkening, which have caused chromatic alterations in the appearance and tonality of the paintings.[1] The understanding of the alteration mechanism, indispensable to orientate the conservation protocols, is not yet fully elucidate despite several studies.[2,3] In order to clarify the discoloration process it is necessary to get information on the geometry of the copper cluster and the nature of the copper-ligand bonds. The observed discoloration of these pigments has led to the research into the effect of environmental conditions surrounding works of art (light exposure, T) thanks to natural and accelerated ageing. With this aim, a multi analytical methodology has been developed coupling the characterization of real ancient painting samples and model systems (made by various proportion of different pigments and binding media). Model samples were investigated by a set of analytical techniques before and after thermic and light ageing: SEM-EDS, IRTF, Raman, UV-Visible, GC-MS, XAS, EPR. The data collected were compared with those obtained from real samples. Preliminary results show that copper concentration is constant between alterated and non alterated zone, and that the darkening seems not influenced by others metals and elements (like calcium, chloride or sulfur). The darkening is related to reaction between copper and bi/tri unsaturated fatty acids, while saturated and monounsaturated compounds are stable. The alteration is not correlated with hydration of the organometallic complexes but is possibly related to reorganization of the metallic cluster.

References [1] C. Altavilla, E. Ciliberto. Appl. Phys. A. 2006, 83, 699-703. [2] M. Gunn, G. Chottard, E. Rivière, J. J. Girerd, J.C. Chottard, Studies in Conservation. 2002, 47(1), 12-23. [3] L. Cartechini, C. Miliani, B. G. Brunetti, A. Sgamellotti, C. Altavilla, F. Ciliberto, F. D’Acapito, Appl. Phys. A. 2008, 92, 243-250.

51 Book of Abstracts P11

Non-destructive micro-Raman and XRF investigation on parade saddles of the Italian renaissance

Pietro Baraldi,1 Davide Gasparotto,2 Claudia Pelosi,3 Paolo Zannini1

1 Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Italy, +390592055087, [email protected] 2 Galleria Estense, Superintendence BSAE Modena and Reggio Emilia, Modena, Italy 3 Department of Cultural Heritage Sciences, University of Tuscia, Viterbo, Italy

Some parade saddles are preserved in Italian Museums and Institutions with typological and structural differences on their decorations. Two saddles are observable in the Museum of the Bargello in Florence and preserve pigments and gildings on their ivory plaques, but enough obscured by the time patina. One of them is similar to the one in the Estense Gallery: it is one of these special saddles that is chronologically placed in the time of Hercules’ Dukedom in Ferrara (1471-1505). The aim of this research was to identify the materials and techniques used in the Renaissance times to prepare the structure of this kind of saddle, to work the tusks for obtaining the plaques to be carved, to place the plaques on the structure and to decorate them with pigments, dyes and metal sheets. For the time elapsed and the exposition in a case in the Estense Gallery, some parts of these aerodynamic structure may have undergone degradation and alterations and the pigments may have changed they hues as a consequence of their molecular changes. Therefore, all the structure was examined and an analytical procedure was prepared so as to take into consideration many materials on the wooden structure.

The surface of the ivory plaques, covering all the surface of the saddle, is almost all well preserved, as can be observed by carefully inspecting all the details and covered areas, where polychrome survivals could be present. This visual inspection with a digital microscope led to the identification of small pigmented areas with bright colours: red, yellow, green blue and black. Some gilding on Hercules’ hair and on the lion mane can be appreciated. XRF measurements (Bruker instrument) were taken on all the colours ascertained and on the wood structure, the parchment intermediate leaves, the white ivory and each coloured small fragments. Infrared spectra were obtained using a Jasco 4200 Fourier transform spectrometer. The spectral range was 4000 to 400 cm-1 in ATR mode with 16 scans and a resolution of 4 cm-1.

The micro-Raman spectrometer used in this case was a HE633 transportable from the Jobin Yvon- Horiba with a spatial resolution of 5 µm and with quick detection ability as a result of the CCD detector 1024x256 pixels cooled to -70 °C by the Peltier effect. The spectral resolution was 10 cm-1. The exciting wavelength was the 632.8 nm red line of a He-Ne laser. A long distance 50x objective was used.

The different ivory plaques of the Hercules of Este saddle exhibit traces of pigments underlining the particular detail. The vegetable parts of the carvings are described by a green composed of a copper salt and an organic part rarely found in artworks. Red is frequently obtained with vermilion, black in the gothic-like writings is in carbon, but in some points there was also indigotine. Both the mane of the lion and of Hercules’s hair are obtained with a gold foil perhaps obtained with the usual gold of the florins of that time. Microscopic details showed the deposition of the gold foil on a whitish preparation with white lead [2]. Blue areas are obtained with a lightly ground azurite, mainly abraded or fallen from those surfaces. In the emblem of the Este that contained blue and yellow, only microscopic areas can still be

RAA 2013 52 P11 seen. Lead white in many small areas was partly transformed into grey plattnerite. The nails were realized with a copper alloy covered with silver. The ensemble of techniques applied enabled the series of materials and particularly pigments of the Hercules’ saddle to be identified. The most difficult one to be identified was the green jelly pigments, an elaboration of verdigris. This kind of artifact is very attractive and other items should be investigated in order to find similarities and differences and supposing, also on the basis of artistic and historical sources, their possible origin.

Acknowledgements The research could not have been carried out without the permission by the Superintendant BSAE of the Provinces of Modena and Reggio Emilia, dr. Stefano Casciu.

References [1] T. Tuohy, Herculean Ferrara, Cambridge University Press: Cambridge, 2009, pp. 187-200. [2] P. A. Andreuccetti, The polychromy of stone sculptures in Tuscany between the XIII and XV century, Polistampa Ed., 2008.

53 Book of Abstracts P12

Phoenicians preferred red pigments: micro-Raman investigation on some cosmetics found in Sicily archaeological sites

Cecilia Baraldi,1,* Giada Freguglia,1 Elsa Van Elslande,2 Pamela Toti,3 Pietro Baraldi,4 Maria Cristina Gamberini,1 Claudia Pelosi5

1 Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy, +390592055157, [email protected] 2 UPMC - Laboratoire d’Archéologie Moléculaire et Structurale UMR 8220, Paris, France, [email protected] 3 “Giuseppe Whitaker” Foundation, Palermo, Italy, [email protected] 4 Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy, +390592055087, [email protected] 5 Department of Cultural Heritage Sciences, University of Tuscia, Viterbo, Italy, +390761357684, [email protected]

This research was undertaken in the aim of identifying and getting deeper knoowledge into materials and pigments used in cosmestics concerning the contest of the phoenician settlements in Sicilian territory. In fact, about the typologies of cosmetics in use among the Phoenicians, little is known. On this subject, generally references come from bibliographic latin sources: in antiquity, women preferred to paint white their face, red lips and cheeks, yellowish eyes and black to sorround their look (Pliny the Elder, Naturalis Historia; Ovidius, De medicamine faciei feminae). An interesting aspect of this research is that just one paper is known on Punic cosmetics.[1] In the Museo Archeologico Regionale “Antonino Salinas” (Palermo, Sicily) an important collection of unguentaries coming from the town of Selinunte is preserved. Some of them, finely crafted, come from the sanctuary of Demetra Malophoros, some unguentaries come from the acropolis and some more from the necropolis (dating from the 6th to the 5th century b. C). The sacred area, excavated by Cavallari (1818) and Salinas (1903-1905), have provided a great amount of archaeological materials. In the area where once the acropolis rose, the remains show a mixed village, Phoenician and Greek. In this study, the findings from Salinas were considered, as well as some others from the Museum Conte Agostino Pepoli (Trapani), from the Museum Baglio Anselmi (Marsala) and from the museum of Mozia. The number of glass and fictile unguentaries, pyxis and alabastra examined were large: 142 items from Salinas, 210 from Mozia, 14 from Pepoli and 117 from Baglio Anselmi. This research has completed the one carried out on 210 samples from the Museum of Whitaker Foundation from Mozia, a merely phoenician –punic settlement.[2,3] The samples were analyzed by spectroscopic techniques. The IR spectra were acquired with a spectrophotometer VERTEX 70 (Bruker) FT-IR, equipped with a detector deuterium triglycine sulphate (DTGS). The setting parameters were: resolution 4 cm-1, spectral range 4000-600 cm-1, number of scans 32. ATR spectra were recorded using an Elmer Golden-Gate accessory. The micro-Raman spectrometer used in this case was a Labram Model from the Jobin Yvon-Horiba with a spatial resolution of 1 µm and with quick detection ability as a result of the CCD detector 1024x256 pixels cooled to -70°C by the Peltier effect. The spectral resolution was 1 cm-1. The exciting wavelength was the 632.8 nm red line of a He-Ne laser. Generally the samples were presented as inorganic powders of different colors: white, black, blue and

RAA 2013 54 P12 red. Though the samples came from different museums, they were considered togheter, since they belonged all to the Phoenician culture and coming from Trapani archaeological sites. The white samples were of two types. The first one was mainly composed of gypsum and anhydrite mixtures (e.g. Inv No 1680, 1663, 1753); the other type (e.g. pyxes Inv N° 1393, 1451) was composed of fully carbonated cerussite, gypsum and litharge. The second kind of cosmetic corresponded to the most famous Greek cosmetic, called psymition, used by women to white the skin. The first type suggested that, for the same use, alternative materials, cheaper and most readily available, could be employed in the past. The black powders, usually used to outline the eyes, were mostly given by carbon obtained from vegetable combustion (e.g. Inv. N° 1566, 2314, 4313) or, sometimes, from bone combustion (animal charcoal) as for the samples Inv. N° 3140, 1761. A single blue powder (Inv N° 42259) was consisted by the famous Egyptian blue (CaCuSi4O10). The love for the red color by Phoenician is evident from the great number of powders of this color, probably used to give color to the cheeks or lips. A wide variety of red minerals was found. In many cases the presence of hematite (e.g. Inv N° 2309, 2689, 4269) was detected. A large number of pink and red powders containing cinnabar (unguentaries Inv N° 1393, 6480-1, 34396) was observed. No frequent and very interesting is in fact the HgS finding powder intoalabastra (e.g. Inv. N° 7317/7, 1255), a holder typically used to contain ointments. Another red pigment was identified as red lead (e.g. Inv N° 1606). Finally, a singular discovery was the presence of red lead chromates chrocoite and phoenicochroite, two very rare minerals (e.g. sample Inv. N° 805, 1-98-2, 4386). In fact, they have never been previously attested for cosmetic use, and also rarely attested in paintings before the end of the 18th century when it began to be produced industrially. [4] The high number of Phoenicians samples taken into examination has allowed to understand the typology of raw materials used by the Phoenicians settled in Sicilian contexts. In this study affects the materials heterogeneity used for the make-up, even for example in comparison to the Roman culture, for which there has come a greater number of samples (sites such as Pompeii, Herculaneum and Oplontis were analyzed by our research group),[5-7] but which revealed a palette less extensive and less refined. In particular, this study identified the use of many kind of red pigments, also very rareof mineral origin.

Acknowledgement. The project couldn’t have been carried out without the kind permission granted by the Superintendence of Cultural Heritage (Palermo), Museo Archeologico Regionale “Antonino Salinas” (Palermo), Museo Regionale Pepoli (Trapani), Museo Archeologico Regionale Baglio Anselmi (Marsala).

References [1] Huqet al., Combined, Appl. Phys. A, 2006, 83, 253–256. [2] G. Freguglia, C. Baraldi, M. C. Gamberini, P. Toti, P. Baraldi, PRIN07- Colors and balms in antiquity: from the chemical study to the knowledge of technologies in cosmetics, painting and medicine. Aboca, Sansepolcro (Arezzo, Italy), 2-3th December 2010, p. 50-51. [3] Baraldi, G. Freguglia, M.C. Gamberini, P. Baraldi, 5-8th September 2011, RAA2011, Parma, 2011, p. 103- 104. [4] R. J. H. Clark. Chimie, 2002, 5, 7–20. [5] P. Baraldi, C. Fagnano, C. Baraldi, M.C. Gamberini, Automata. 2006, 1, 49. [6] M. C. Gamberini, C. Baraldi, F. Palazzoli, E. Ribechini, P. Baraldi, Vib. Spectrosc. 2008, 47/2, 82. [7] E. Van Elslande, M. C. Gamberini, C. Baraldi and P. Walter, An overview of the Raman studies on cosmetic powders from Pompeii, 14-18th September 2009. RAA2009, Bilbao, 2009.

55 Book of Abstracts P13

Raman microscopy and X-ray fluorescence for the rediscovering of polychromy and gilding on classical statuary in the Galleria degli Uffizi

Pietro Baraldi,1 Paolo Bensi,2 Alessandro Muscillo,3 Fabrizio Paolucci,3 Andrea Rossi,4 Paolo Zannini1

1 Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Italy, +39 0592055087, [email protected]. 2 Department of Sciences for Architecture, University of Genua, Italy 3 Ministry for Cultural Heritage, Uffizi Gallery, Florence, Italy 4 Center for Multispectral Analyses, Modena, Italy

The Uffizi Gallery in Florence is mainly known for its patrimony of Gothic and Renaissance painting, but it has also a considerable collection of Greek and Roman statues. The collection is one of the oldest in Europe and derives from the Medici personal collection and from acquirements during the centuries and donation from noble families. Great part of the statuary is not exposed in the Gallery, and in the aim of showing to the public a greater number of them, the new Museum of Villa Corsini on the hills of Florence was open last year. All the statue have a long stay in the Gallery and/or in the depositories, so that many need a control for their present conservation state. Therefore, a research program was set up in order to control the statues that in turn will be reconsidered for an exhibition or a re-proposal. The items will be studied firstly as they are, nextly as they will be under cleaning and after cleaning, in such a way to follow every detail of the surface and to put in evidence the survivals of polychromy, of metal laminas, the encrustations, the corrosion signs and the biological trace of attack by vegetables. This program is now in progress and till present the procedure has been applied to some famous masterpieces placed in the Tribuna. Some of them showed survival of interesting materials that offer new points for discussion of chronology of art materials and techniques. Research of this kind is now applied in European Museums and devoted to Greek and Roman statuary. [1-7]

Figure 1. XRF (left) of the preparation for gilding and Raman spectra (right) of the yellow layer with Lead tin yellow type I.

A careful observation of the artwork surface with a digital microscope enabled to identify the points where microscopic traces of pigment or metal foil were still present. Some portable instrumentation were used to identify the materials, when their surface was enough large for a specific technique. In some cases, a microsample was taken and placed in a vial for the analysis in the laboratory. For the research in progress many analytical techniques were used, especially those that were n-destructive. The techniques employed were mainly: Raman microscopy, FT-IR spectrometry and microscopy, X-ray fluorescence spectrometry, Visible induced luminescence (VIL) and multispectral analyses. In comparing the results obtained from the different techniques care must be taken for the apparent

RAA 2013 56 P13 inconsistency of some results. Beyond the spectral resolution, spatial resolution must be included. This comparison could be helpful, for an accurate investigation, by putting in evidence traces of materials that in other techniques could give only low level signals. For the Raman spectra portable Jobin Yvon HE633 instrumentation was used, with a 633 nm red laser, a CCD with 256 x 1024 pixels cooled to -70°C by the Peltier effect. Laser power was at most 5 mW, but frequently it was reduced to 1/10, and accumulation time was from some few seconds to some minutes. As a first example, we recall the presence of Lead Tin yellow type I that was identified on the Venere Medici’s head. It was known that in the 18th century, during the Grand Tour to Italy, the statue exhibited still a golden hair, subsequently not more observable. Some fragments are still observable, but giallolino is a new finding for the Roman chronology. Other interesting founds are traces of lazurite on some sarcophagus, that were neither repainted nor restored previously, only having been plastered for making the surface uniform and having been integrated with marble fragments in some parts. Other interesting findings on sarcophagus were spots of lazurite alternating with aegyptian blue ones clearly observable con with VIL technique of investigation. Rarely it was also found cinnabar, often on a preparation with glue and lead white. Multispectral investigation showed details of previous works on the surfaces. In view of the data here reported, it seems advisable to carry out more investigations on the classical statues preserved in the Italian Museums. In fact, though their heavy past restoration processes are identifiable, some survived polychromy can be ascertained with careful inspection and analyses. The combination of the techniques examined is important since it could supply information on both polychromy and metal foils. The materials used in the past for gilding can give information on their chronology.

Acknowledgements This work has been financially aided by the group of »Friends of the Florentine Museums«.

References [1] H. Bankel, P. Liverani, I colori del bianco. Policromia nella scultura antica (The colors of white, Polychromy in ancient sculpture), De Luca Editori d'Arte: Roma, 2004. [2] P. Bensi, Recovering the ancient art techniques between the end of Eighteenth and the first decades of Ninenteenth Centuries, Actes of 3rd seminary “Decennio francese” (1806-1815), Santa Maria Capua Vetere, 10-12 october 2007, Napoli, 2010, p. 101-116. [3] V. Brinkmann, Die Polychromie der archaischen und frühklassischen Skulptur, Biering & Brinkmann: Monaco, 2003. [4] V. Brinkmann, O. Primavesi, M. Hollein, Looking for colour on Greek and Roman Sculpture„ Circumlithio: polychromy of antique and medieval sculpture“, J. of Art Historiography, 2011, 5. [5] P. Jockey, B. Bourgeois, La dorure des marbres grecs. Nouvelle enquête sur la sculpture hellénistique de Délos, J. des savants. 2005, N°2, 253–316. [6] Ny Carlsberg Glyptotek the Copenhagen Polychromy Network, Tracking colours, The Polychromy of greek and roman sculpture in the Ny Carlsberg Glyptotek, Preliminary report 1, 2009; Preliminary report 2, 2010; Preliminary report 3, 2011. [7] R. Panzanelli, The color of life. Polychromy in sculpture from antiquity to present. The J. Paul Getty Museum – The Getty Research Institute: Los Angeles, 2008.

57 Book of Abstracts P14

Raman spectroscopic investigation of black pigments

Alessia Coccato,1* Peter Vandenabeele,1 Luc Moens2

1 Department of Archaeology, Ghent University, Belgium, [email protected], [email protected] 2 Department of Analytical Chemistry, Ghent University, Belgium

A variety of black pigments were selected for a detailed study by means of Raman spectroscopy. The well-established and appreciated advantages of this technique for the study of cultural heritage objects, in the case of black pigments investigation, are mitigated by some difficulties, as the weak scattering produced by some pigments, and their high absorption of visible light. The selected pigments cover a wide range of carbonaceous materials, of metal oxides and other materials (i.e. sepia black, tourmaline), already identified in cultural heritage objects by means of other techniques (X ray diffraction [1], colorimetry [2], FTIR and SEM-EDS [3]. Old painting treatises provide detailed receipts for preparing pigments, but ambiguity and misunderstandings in the naming may occur when matching different authors [4]. Furthermore, just a few studies dedicated to Raman spectroscopy of carbon black pigments have been published [5], while the study of carbonaceous material of geological and industrial interest are quite common [6], [7]. The common practice is to use the term “carbon black” for all the pigments showing two broad bands centred around 1580 and 1300 cm-1, with few exceptions (e.g. bone/ivory black can be identified if phosphates stretching is present at ~960 cm-1). For metal oxides, some reference spectra are published in the specific field of archaeometallurgy [8]. For sepia melanin black pigment only SERS Raman spectra were available for comparison [9], [10]. Tourmaline black is studied as a mineral and a gem. The aim of our study is to provide an overview of the Raman spectra of different black artists’ materials and to propose a nomenclature.

Figure 2. Raman spectra of selected black pigments, from top to bottom: powdered ivory black, ivory black in pieces and spinel black.

Raman spectra were collected using a Bruker Senterra spectrometer, equipped with two excitation lines (532 and 785 nm). As expected, the spectra of carbon blacks are all quite similar to each other, with two broad bands centred at 1580 and 1320 cm-1, but some differences may be highlighted. Obviously, a single crystal of graphite gives a recognizable spectrum, with narrow an well separated bands; but as the disorder in the solid phase increases, bands shift and new ones arise, in addition to the G (1580 cm- 1) and D1 (1350 cm‑1) bands [7], so the deconvolution process for estimating the band position and width has to take this into account. Moreover, some pigments had additional bands in their spectra. In some

RAA 2013 58 P14 cases these were helpful in identifying particular types of carbon black, as carbonates in Black Earth from Andalusia, which is supposed to be a mixture of carbonaceous materials with quartz and calcite, or as in the case of the phosphate vibrations, that indicates a black derived from bones calcination (Ivory black). But in some other cases some unexpected bands showed up, revealing the presence of contaminants in specific carbon black pigments. Specifically, it was possible to identify Spinel Black bands together with others, as in Black Chalk, whose composition is not well defined, and also in Sepia, Ivory black and in Graphite powder (Figure 1). For these latter samples, the presence of such materials is highly unexpected. As regards to metal oxide black pigments (iron and manganese, mainly), it has been noted that high laser power (1,4 mW for 532 nm line, 7,4 mW for 785 nm line) induces a red coloration of the Mars Black Iron Oxide 318 pigment, and burns Manganese black. Good quality spectra were generally obtained with green excitation, at its lowest possible power, with long measurement times. The first results of this research confirm the effectiveness of Raman spectroscopy in the study of dark pigments, as the possibility of identifying many black pigments through a non-destructive technique and of distinguishing among different carbon blacks.

References [1] N. Buzgar, A. I. Apopei, A. Buzatu, J. of Archaeological Science. 2013, 40(4), 2128–2135. [2] T. Gatta, L. Campanella, C. Coluzza, V. Mambro, P. Postorino, M. Tomassetti, G. Visco. Chemistry Central J. 2012, 6 Suppl 2(2), S2. [3] E. P. Tomasini, G. Siracusano, M. S. Maier, Microchemical J. 2012, 102, 28–37. [4] Butterworth-Heinemann (ed.), Pigment Compendium: A Dictionary of Historical Pigments, Elsevier Butterworth-Heinemann: Burlington, Massachussets, 2005. [5] E. P. Tomasini, E. B. Halac, M. Reinoso, E. J. Di Liscia, M. S. Maier, J. of Raman Spectrosc. 2012, 43(11), 1671–1675. [6] O. Beyssac, B. Goffé, J.-P- Petitet, E. Froigneux, M. Moreau, J.-N. Rouzaud, Spectrochimica Acta Part A. 2003, 59(10), 2267–2276. [7] J. Jehlička, O. Urban, J. Pokorný, Spectrochimica Acta Part A. 2003, 59(10), 2341–2352. [8] M. Bouchard, D. C. Smith, Spectrochimica Acta Part A. 2003, 59(10), 2247–2266. [9] A. Samokhvalov, Y. Liu, J. D. Simon, Photochemistry and Photobiology. 2007, 80(1), 84–88. [10] S. A. Centeno, J. Shamir, J. of Molecular Structure. 2008, 873 (1-3), 149–159.

59 Book of Abstracts P15

Raman Spectroscopy and SEM-EDS Studies Revealing Treatment History and Pigments of the Government Palace Tower Clock in Helsinki Empire Senate Square

Kepa Castro,1* Maite Maguregui,1 Silvia Fdez- Ortiz de Vallejuelo,1 Raili Laakso,2 Ulla Knuutinen,3 Juan Manuel Madariaga1

1 Department of Analytical Chemistry, University of the Basque Country (UPV/EHU), Bilbao, Spain, +34 946018297, [email protected] 2 Helsinki Metropolia University of Applied Sciences, Finland 3 Department of Art and Culture Studies, University of Jyväskylä, Finland

Combined restoration and material research of the tower clock of the Government Palace (originally the Senate) in Helsinki has been a remarkable cultural heritage project. The Government Palace is a typical Empire palace in Empire center of Helsinki, where buildings around the Senate Square are internationally significant example of the neoclassical style. The German-born architect Carl Ludwig Engel (1778-1840) designed The Government Palace, the Cathedral, the main building of the University of Helsinki and the Helsinki University Library. The first building to be completed in 1822 was the Senate. The tower clock of the Senate is Finnish origin and made by the famous watchmaker family Könni. The clock has two faces: one towards the Senate Square and the other facing the courtyard. The clock faces are nearly 1,5 meters in diameter. Architect Engel had drawn detailed instructions for the machinery of the clocks at the desired characteristics.

Worn parts of the machinery of this 190 years old clock have been replaced as needed over the decade and the plates have been in their original place until 2010. The colour of the clock faces has been altered several times. Under the light blue coating there were found several other color layers. For the restoration, it was needed to identify the first black layer, because the clock was decided to restore with its original color. The other paint layers were important, because they provided information and dating about treatment history and pigments used in Finland after 1822. In the 19th century a wide range of new industrial pigments were replacing old traditional pigments in Europe. However, there are only few case studies about the use of these new pigments in Finland.[1]

Material research of the clock faces was prepared in two steps. First, preliminary elemental analyses with portable, non-invasive InnovX, EDXRF were carried out and microphotographs from paint layers cross-sections were also acquired. Then, the studies continued with Raman and SEM-EDS. Raman analyses were carried out by means of inVia Renishaw confocal microRaman spectrometer coupled to a DMLM Leica microscope provided with 5x, 20x, 50x, 50x (long distance) and 100x lenses using a 514 and a 785 nm excitation lasers. Lasers were set at low power (not more than 1mW at the sample) in order to avoid thermal photodecomposition. Spectra were acquired between 150 and 3200 cm-1 (1 cm-1 spectral resolution) and several scans were accumulated for each spectrum in order to improve the signal-to-noise ratio. In order to obtain Raman chemical images, StreamLine technology was employed. The inVia’s motorised microscope stage moves the sample beneath the lens so that the line is rastered across the region of interest. Data are swept synchronously across the detector as the line moves across the sample, and are read out continuously. The spectral imaging was carried out with the 514nm laser and 785nm laser. The quality of measurements was assured by means of an internal calibration and a diary calibration with a silicon chip. The collected Raman spectra were compared with standard

RAA 2013 60 P15 spectra databases [2] and databases available online such as RRUFF.[3] When necessary, single Raman spectra were also acquired. In addition, SEM-EDS measurements were carried out to determine the elemental distribution images in the cross-section of the samples. The measurements were performed using an EVO40 scanning electron microscope (Carl Zeiss) coupled to an X-Max energy-dispersive X-ray spectrometer (Oxford Instruments). EDS analysis was carried out using a working distance of 8-10 mm, an I Probe of 180 pA, an acceleration potential of 30 kV and 10 scans.

The samples from the clock were analysed as cross-sections in order to identify all restorations that had taken place all along the life of the clock, as well as to determine what its original colour was. Thanks to the analytical methodology carried out, it was possible to determine the presence of the pigments in the different layers of the cross-sections. The original colour seems to be black, that, as time went by, was covered by a red layer, then by a grey layer, then by a blue layer, then by a yellow layer and finally by a blue layer. Pigments such as red lead, hematite, Prussian blue, zinc chromate, massicot, phthalocyanine blue, rutile and carbon black were determined in the different layers. Raman analyses were corroborated by the chemical images provided by SEM-EDS analysis carried out with the same cross-section samples.

Figure 1. Raman spectra of two layer from cross-section; Ma (masssicot), ZY (zinc chromate), PR (Prussian blue) and PH (phthalocyanine blue)

Acknowledgements This work has been partially supported by Global Change and Heritage project (UFI11/26) funded by the University of the Basque Country (UPV/EHU). The authors are grateful for technical and human support provided by the Raman-LASPEA Laboratory of the SGIker (UPV/EHU, MICINN, GV/EJ, ERDF and ESF).

References [1] K. Castro, U. Knuutinen, S. Fdez-Ortiz de Vallejuelo, M. Irazola, J. M. Madariaga, Spectrochimica Acta Part A. 2013, 106, 104–109. [2] K. Castro, M. Pérez-Alonso, M. D. Rodríguez-Laso, L. A. Fernández, J. M. Madariaga, Analytical and Bioanalytical Chemistry. 2005, 382, 248. [3] R. T. Downs, Program and Abstracts of the 19th General Meeting of the International Mineralogical Association in Kobe, Japan, 2006, O03–13.

61 Book of Abstracts P16

Feasibility Study of Portable Raman Spectroscopy for Characterization of Ground Material of Easel Paintings (Case Study: Sradar As’ad-e Bakhtiary Painting of Kamal-al Molk)

Mohsen Ghanooni,1*, Hamid Motahari,2 Rasoul Malekfar, 2 Ehsan Talebian2

1 Department of conservation, Parliament Library & Museum of Iran, Tehran, +989125533047, [email protected] 2 Department of Physics, Tarbiat Modares University, Iran, Tehran

One of the most important approaches for conservators is the exact characterization of art work components. This is important especially for conservation of paintings. Also analysis methods are useful for identification of ground and paint layer components in treatment process. These analysis methods can be divided to nondestructive and destructive methods. However, the first one is far better than the second one for conservators. In order to study the nondestructive methods for conservation of paintings, we have tried to investigate the feasibility study of using a portable nondestructive characterization system. This feasibility study has been used for characterization of painting ground by means of portable back-scattering micro-Raman spectroscopy. The obtained results have been compared with the data obtained from another main systems, Almega Thermo Nicolet Raman scattering spectrometer and FT-IR spectroscopy. Our primary question that is: “Can we rely on the portable Raman data for characterization of the painting ground? Fir this purposes we have analyzed the »Sradar As’ad-e Bakhtiary painting« which was composed by Kamal-al Molk. Kamal-al Molk was the well-known painter of the 19th and 20th centuries of Iran. This tool shows a reliable result but in such cases, we can check the data with a second method such as FT-IR spectroscopy. The recorded spectra from the portable Raman spectrometer shows high agreement when compared with the FTIR spectroscopy results. In addition some difficulties appear, i. e. some ambiguity, from qualitative and quantitative point of view, in analyzing the recorded spectra can arise. However, these can be resolved by using other techniques especially for calibration purposes of the used tools. It is obvious from Figs. 1 of the recorded Raman spectra that a series of peaks observed from 890 cm-1 to 1800 cm-1 as the main fingerprint bases of the origin of the materials used in the painting These peaks are related to Arabic

Figure 1. The Raman spectra of Sample No RP15 belong to ground materials of Sardar As'ad Painting

RAA 2013 62 P16 gum and Bees wax and Gelatin. Also there are some other peaks in the range around 2700 to 3000 cm-1in full spectra that are evidence for using of egg white and yolk in this painting. Finally, from these evaluations we obtain that the portable Raman instrument results are so useful for getting information within superior historical paintings as a main nondestructive test and without any damaging on it. Also the results are consistent with the recorded FTIR spectroscopy results which is located at the laboratory whereas Raman portable system can be carried out to the situation of the painting. The final consistency and agreement between the data obtained from the portable Raman and the FTIR spectrometers appear that the recorded data are completely convincing but the Raman portable system is very simple and can be applied for every painting and regardless of its place. Therefore we can claim that the Raman portable system can be considered as the ideal tool for the analysis purposes of historical paintings.

References [1] K. Castro, M. D. Rodrigues-Laso, L. A. Fernandez, Madariaga, J. Raman Spectros. 2001, 33, 17–25. [2] L. Burgio, R. J. H. Clark, Spectrochim. Acta Part A. 2001, 57, 1491–1521. [3] Z. E. Papliaka, K. S. Andrikopoulos, E. A. Varella, J. of Cultural heritage. 2010, 11, 381–391. [4] A. Duran, M. L. Franquelo, M. A. Centeno, T. Espejoc, J. L. Perez-Rodriguez, J. Raman Spectrosc. 2011, 42, 48–55. [5] T. Aguayo, E. Clavijo, F. Eisner, C. Ossa-Izquierdo, M. M. Campos-Vallette, J. Raman Spectrosc. 2011, 42 2143–2148. [6] G. Simsek, Ph. Colomban, V. Milande, J. Raman Spectrosc. 41 (2010) 529–536. [7] T. R. Ravindran, A. K. Arora, S. Ramya, R. V. Subba Raob, B. Raj, J. Raman Spectrosc. 2011, 42, 803–807. [8] C. Miguel, A. Claro, A. P. Goncalves, V. S. F. Muralha, M. J. Melo, J. Raman Spectrosc. 2009, 40, 1966– 1973.

63 Book of Abstracts P17

The Sibyls from the church of San Pedro Telmo: a spectroscopic investigation

Marta S. Maier,1* Fernando Marte,2 Valeria P. Careaga,1 Dalva L. A. de Faria3

1 UMYMFOR - Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, CABA, Argentina, [email protected], [email protected] 2 CEIRCAB-Tarea, Universidad Nacional de San Martín, CABA, Argentina, [email protected] 3 Instituto de Química, Universidade de São Paulo, Butantã, São Paulo, SP, Brazil, +55 11 30913853, [email protected]

The series of the Sibyls from the church of San Pedro Telmo in Buenos Aires is one of the most important groups of paintings of argentine colonial art.[1] These twelve paintings depict the Sibyls prophesy- ing on episodes of the life of Christ (Figure 1). Ten of them were performed in the 18th century while those correspond ing to the Delphic and Tiburtine Sibyls were painted in 1864 during the first restoration of the series in order to replace the originals due to their poor state of conservation.

Figure 1. Sibyl Samia, 18th century (left) and Delphic Sibyl (1864) (right)

There are two attributions regarding the origin of these paintings, one points to a Spanish origin while the other one suggests that they were painted in a workshop of the Cuzco region. During a restoration of the series in 2005 several microsamples were extracted from original and repainted areas of the twelve paintings and analyzed by Raman microscopy and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS). High performance liquid chromatography (HPLC) was applied to confirm the presence of organic pigments. The aim of our work was to establish if there were differences in the color palette of the 18th and 19th centuries Sibyls and if it was possible to contribute to the elucidation of the origin of the series based on the materiality of the paintings. Light microscopy examination of the cross-sections of the samples revealed a thin pigment layer and a grayish preparation layer. In those samples taken from repainted areas, two pigment layers were observed. Raman microscopy revealed the presence of vermilion in the intense red areas as well as mixed with basic lead carbonate in the carnations. Lazurite (main bands at 546 and 1091 cm-1) was identified

RAA 2013 64 P17 in a green sample taken from a repainted area in admixture with a yellow component, presumably an organic colorant. The blue pigments were identified as indigo in the 18th century Sibyls and Prussian blue in the Delphic and Tiburtine Sibyls. Both blue pigments have been used in Europe and in South American colonial art in the XVIII century.[2] The faded red lake from the Samia robe was identified as alizarin. This is the main anthraquinone colorant of madder, which comes from the roots of Rubia tinctorum.[3] Identification of this pigment suggests a Spanish origin of the series in accordance with historical data. Although red lakes have been used in colonial South American art, only carmine, the red lake obtained from cochineal has been identified in paintings from the Andean region.[4]

Acknowledgements This work has been financially supported by the National Research Council of Argentina (CONICET), the University of Buenos Aires, and the National Scientific Agency of Argentina (ANPCyT).

References [1] A. Rodríguez Romero, J. E. Burucúas, Las 12 Sibilas de la Parroquia San Pedro G. Telmo. Un trabajo de conservación y de crítica histórica, UNSAM: Buenos Aires, 2005, p. 26. [2] A. Seldes, L. E. Burucúa, M. S. Maier, G. Abad, A. Jáuregui, G. Siracusano, J. A. I. C. S. 1999, 38, 100. [3] H. Schweppe, J. Winter, Artists’ Pigments. A handbook of their History and Characteristics, vol. 3, Nation- al Gallery of Art: Washington, 1997, p. 109. [4] A. Seldes, J. E. Burucúa, G. Siracusano, M.S. Maier, G. Abad, J. A. I. C. S. 2002, 42, 225.

65 Book of Abstracts P18

Pigment identification of illuminated medieval manuscripts by means of a new, portable Raman equipment

Debbie Lauwers,1* Vincent Cattersel,2 Annabel Van Eester, 2 Ine Craenhals,2 Jitske Van Groenland,2 Luc Moens,1 Peter Vandenabeele3

1 Department of Analytical Chemistry, Research Group Raman Spectroscopy, Ghent University, Belgium, +32 (0)9 264 47 19, [email protected], [email protected] 2 Artesis university College of Antwerp, Belgium, [email protected] 3 Department of Archaeology, Archaeometry research group, Ghent University, Belgium, +32 (0)9 264 47 17, +32 (0)9 331 01 66, [email protected]

Direct identification of pigments in medieval illuminated manuscripts was one of the first applications of Raman spectroscopy in art and archaeology.[1] In previous in-situ analysis of handwritings the equipment was typically provided with only one excitation source.[2-4] In this work a new mobile Raman spectrometer, EZRAMAN-I-DUAL Raman system (Enwave Optonics, Irvine CA, USA) is introduced to characterise the pigments used in different medieval manuscripts from the library in Bruges (Civitate Dei (Ms.106), Chronicles of Flanders (Ms.437), Cistercian manuscripts (Ms.27, 35, 140 and 142)). This Raman spectrometer has the advantage to interchange between two laser wavelengths (785nm and 532nm). The investigated manuscripts originate from the collection of the abbey ‘Ten Duinen’ (Koksijde, Belgium) and are preserved in the city library of heritage in Bruges, Biekorf. Civitate Dei (Ms.106) was written during the second half of the 15th century by Aurelius Augustine (~ St Augustine) and consists of 22 parts with a total of 262 folios. On folio 22r a miniature, attributed to Willem Vrelant, a decorated initial, a fleuronnée initial, and a colourful frame were examined.[5] Chronicles of Flanders (Ms. 437, 15th century) was written by Antonius the Roovere, one of the famous authors during the 15th century. Research focussed on illuminations on the historical events during the reign of Mary of Burgundy (e.g. The accolade of Maximilian of Austria during the chapter of ‘the Golden Fleece’ in Bruges in 1478).[6] The third series of manuscripts that were examined, were Cistercian manuscripts (Ms. 27, 35, 140 and 142). These four manuscripts date from the 12th century and are probably produced in their own scriptorium.[7] Despite their sober illumination, interesting green, blue and red areas were characterised . As mentioned, the Raman analysis was performed by a new mobile instrument, EZRAMAN-I-DUAL Raman system. The fiber-optic-based device is equipped with two type of lasers, a red diode laser (785 nm) and a green Nd:YAG laser (532 nm) and has three interchangeable lenses: a standard lens (STD), a long working distance lens (LWD) and a high numerical aperture lens (HiNA). The Raman spectrometer also consist of an adjustable power controller for each laser and a CCD detection system. When comparing this instrument to other portable spectrometers, several practical advantages can be observed. Besides the advantage that one can interchange between the lasers, the instrument can work both on battery (live time of 6h 30min) or external power supply. This increases the on-site working possibilities. When performing direct analysis, good quality positioning (i.e. focussing) of the equipment is of utmost importance to obtain high quality results.[8] It is required to have a stable equipment and the way the instrument is mounted must be save. Apart from the requirement for stable positioning equipment, it should also allow for easy macro and micro-positioning. Figure 1 represents the set-up used for correct positioning of the instrument for direct Raman analysis of the manuscripts, by means of an articulating arm. By using this approach different pigments were examined. In spite of a strong fluorescence background,

some preliminary results could be made: pigments such as lead white (2PbCO3·Pb(OH)2), lead–tin yellow

RAA 2013 66 P18

type I (Pb2SnO4), massicot (PbO), vermilion (HgS), red lead (Pb3O4) and azurite Cu3(CO3)2(OH)2 could be identified. These pigments were often used in medieval artworks,objects which indicate the authenticity of the manuscripts.

Conclusion. It can be concluded that the new mobile Raman spectrometer, EZRAMAN-I-DUAL Raman system, is a very good device for the identification of pigments. The investigation of the medieval manuscripts (Civitate Dei, Chronicles of Flanders, Cistercian manuscripts) results in the identification of , amongst others, lead white (2PbCO3·Pb(OH)2), lea-tin yellow type I (Pb2SnO4), massicot (PbO), vermilion (HgS), red lead (Pb3O4) and azurite (Cu3(CO3)2(OH )2), – which is in agreement with the medieval artists’ palette.

Figure 1. Image of the way of positioning the spectrometer a.); Overview of the total set-up b.).

Acknowledgements We would like to thank the library of Heritage, more specifically Dr. Ludo Vandamme for the disposal of the medieval manuscripts. The research is financially supported by the European Commission, through the FP-7 MEMORI project ‘Measurement, Effect Assessment and Mitigation of Pollutant Impact on Movable Cultural Assets. Innovative Research for Market Transfer‘ (http://www.memori-project.eu/memori.html).

References [1] P. Dhamelincourt, P. Bisson, Microsc. Acta. 1977, 79, 267–276. [2] A. Deneckere, M. Leeflang, M. Bloem, C. A. Chavannes-Mazel, B. Vekemans, L. Vincze, P. Vandenabeele, L. Moens, Spectrochimica Acta Part A. 2011, 83, 194–199. [3] D. Bersani, P. Lottici, F. Vignali G. Zanichelli, J. Raman Spectrosc. 2006, 37, 1012–1018. [4] P. Vitek, E. Ali, H.G.M. Edwards, J. Jehlicka, R. Cox, K. Page, Spectrochimica Acta Part A, 2012, 86, 320-327. [5] R. Vercruysse, Drie Vlaamse Cisterciënzer abdijen en hun bibliotheken, OKV: Belgium, 2002; 2. [6] J. Oosterman. Tijdschrift voor Nederlandse Taal en Letterkunde, 2002, 118, 22–37. [7] W. Le Loup, Vlaamse kunst op perkament: handschriften en miniaturen te Brugge van de 12de tot de 16de eeuw, Brugge: Stadsbestuur, 1981, 81–82. [8] P. Vandenabeele, K. Castro, M. Hargraeves, L. Moens, J.M. Madariaga, H. G. M. Edwards, Analytica Chimica Acta. 2007, 588, 108–116.

67 Book of Abstracts P19

Micro-Raman identification of pigments on wall paintings: characterisation of Langus and Sternen’s palettes

Petra Bešlagić,1* Martina Lesar Kikelj1

1 Restoration Centre, Conservation Centre, Institute for the Protection of the Cultural Heritage of Slovenia, Slovenia, +386 1 2343 120, [email protected]

The conservation and restoration of wall paintings in six side chapels in Franciscan Church of the Annunciation, Ljubljana, Slovenia were carried out between 2006 and 2012. Paintings were painted in fresco and secco techniques between 1845 and 1855 by Matevž Langus (1792- 1855), who was in his time one of the most esteemed Slovenian painter. A few decades later, in 1882 Janez Wolf partly preserved, and in some places overpainted or newly painted one of the chapels, St. Francis chapel. After the earthquake in 1895 all chapels were partly restored by two Viennese painters, Klainert and Kastner. A large number of restoration works in the past changed the appearance to such an extent that in some places the original image area and plaster were gone. Because of that, the biggest intervention in the chapels was carried out in between 1925 and 1933 by Matej Sternen (1870- 1949), impressionist painter and restorer, who applied new plaster and paint layers. Sternen also newly painted the vaulted nave and presbytery between 1935 and 1936.[1,2] In 2006 wall paintings in the chapels were severely deteriorated due to poor technology and quality of plaster, pollution of the urban environment, the problems of moisture, salt crystallization and inappropriate choice of consolidants in past restoration interventions. During the restoration process of some areas of the painting, it was not completely clear which areas of paintings are the work of Langus or Sternen. Because of that, the aim of our work was to identify pigments that those two painters used for the execution of wall paintings. Samples taken from chapels were analysed and pigments were identified. We also analysed several samples of paint layers taken from Sternen’s painting of vaulted presbytery ceiling in Franciscan Church of the Annunciation for the characterization of his palette. For the characterisation of Langus’s palette we analysed paint samples taken from painted vault of large dome in Church of the Mother of God, Šmarna gora, Ljubljana. Samples of paint layers were taken from different colour areas of paintings and prepared as cross- sections, having been embedded in polyester resin and polished. Cross-sections were examined by using optical microscope as well as micro-Raman spectrometer. Raman spectra of paint layers were obtained by using 633 and 785 nm laser excitation line with a Horiba Jobin Yvonne LabRAM HR800 Raman spectrometer equipped with Olympus BXFM optical microscope, a grating with 600 grooves per mm and an air-cooled CCD detector. Some of the samples were also analysed with SEM/EDS and micro-FTIR. The results showed that Langus and Sternen palettes are very similar: differences may be found in the green and red pigments. Size of used pigments and also combination of pigments was different in Langus and Sternen’s palettes. Samples taken from the chapels were evaluated and in some cases, but not in all (because of the similarities in their palettes), we could determine if paint layer was work of Langus or Sternen’s. The present micro-Raman study of pigments used by Langus and Sternen provide important information on used pigments and their palettes. Results can be used for future conservation and restoration purposes and also as a help for future investigations on Langus and Sternen’s wall paintings.

RAA 2013 68 P19

References [1] F. Stele, Kronika slovenskih mest. 1935, 2(3), 221–226. [2] J. Dostal, Dom in svet. 1937/1938, 50(7), 332–338.

69 Book of Abstracts OP8

New Methods in Raman Spectroscopy – Combining Other Micro- scopes for mineral and pigment analysis

Josef Sedlmeier,1* Alan Brooker, 2 Kenneth Williams3

1 Renishaw s.r.o., Brno, Czech Repubblic, +420 548 428 725, [email protected] 2 Renishaw Plc., Glos, United Kingdom, +44 0 1453 524 524, [email protected] 3 Renishaw Plc., Glos, United Kingdom, +44 0 1453 524 524, [email protected]

Introduction. The advantages of using an optical microscope coupled to a Raman spectrometer have been well documented over the last three decades. The advances in filter technology made it possible to develop the “bench top” Raman microscope systems that have dominated the market place for the last ten years. The ease of use which has accompanied these advances in instrumentation has led to a rapid expansion in the use of the Raman technology over many diverse fields, such as materials research, chemical catalysis, biochemical and biomedical, through to art restoration and gemmology. Given the level of interest and the diversity of applications, new demands are now being made by researchers to move away from using traditional optical microscopy to visualise their samples. The purpose of this presentation is to detail the very recent advances that have been made in combining a variety of alternative microscopes to identify the sample area of interest on which a Raman analysis can be performed. We have been working with Smiths Industries to combine the Renishaw Raman microscope with their infrared (FT-IR) system, to produce a combined Raman/infrared microscope capable of integrated vibrational analysis. In addition we have worked with a selection of scanning electron microscope manufacturers to provide Raman analysis from materials inside the SEM.

Results and Discussions The combined analysis by Raman and infrared spectroscopes offers a real benefit for “same spot” investigation, together with the obvious advantages of acquiring a complete vibrational picture of the sample. The technology employed is relatively simple but utilises a conventional Raman microscope which can allow an infrared beam to pass down unobstructed to the sample. The objective lens used is a diamond AFR cell, the diamond of which is transparent to the incident Raman laser beam.

The SEM structural and chemical analyser (SEM-SCA) combines both SEM and Raman techniques into one system, so that users can take full advantage of the high spatial resolution afforded by the SEM, and the chemical information revealed by Raman. This unique combination enables SEM manufacturers to supply a SEM-Raman system that enables the spectrometer to »see« the same area as the SEM - a micrometer-scale laser spot is projected onto the surface of a sample visible in the SEM image. The SEM-SCA hardware can be fitted to most SEMs without compromising the SEM performance in any way. The nature of Raman spectroscopy means that its performance is unaffected by the SEM environment - high vacuum (HV), low vacuum (LV), environmental (ESEM), and high or low (cryogenic) temperatures. The advantages of this method are from the SEM view that SEM overcomes the limitations of optical microscopy with respect to: (a) depth of field - the SEM retains good depth of field even at high magnifications. (b) contrast - SEM contrast mechanisms can easily distinguish optically identical or similar materials. (c) spatial resolution - SEM spatial resolution is typically 3-4 orders of magnitude better than optical microscopy.

Raman spectroscopy meets unfulfilled SEM/EDS analytical requirements: (a) EDS yields elemental information only whilst Raman provides structural, chemical, and physical information. (b) EDS is

RAA 2013 70 OP8 poor for analysing light elements whilst Raman is sensitive to light element chemistry. The instrument can also perform photoluminescence (PL) and cathodoluminescence (CL) studies as the SEM-SCA collection optics are fully compatible with both PL and CL spectroscopes. The former uses a laser as the excitation source, the latter the electron beam. Each technique can reveal both electronic and physical information about the sample, with CL being sensitive to very subtle changes in composition and residual strain. Examples will be presented from topical areas including pigment and minerals analysis and forensic science applications.

71 Book of Abstracts OP9

Horiba Jobin Yvon advances in Raman instrumentation: explore new boundaries in art and archaeology

Romain Bruder1*

1 HORIBA Scientific, Research Division, HORIBA Jobin Yvon S. A. S., Palaiseau – France, [email protected]

Horiba Jobin Yvon is a world leader in Raman spectroscopy. As such, Horiba Jobin Yvon continuously innovates to meet evolving requirements in the different application fields of Raman spectroscopy.

This presentation aims at introducing the latest developments carried out by Horiba Jobin Yvon in terms of Raman microscopes and instrumentation.

From analytical instruments, with the new XploRA ONE microscope, rugged and designed for micro- Raman routine analysis, towards high-end systems such as the new LabRam HR Evolution, Horiba Jobin Yvon proposes a range of micro-Raman spectrometers well suited to the needs of art and archaeology studies. May it be to simply identify pigments or to study in depth corrosion mechanisms and products, newly designed options and accessories, enabling fast mapping, database identification or transmission Raman, bring valuable information to cultural heritage specialists.

Figure 1. XploRA OneTM – Figure 2. LabRam HR EvolutionTM – Horiba Jobin Yvon Horiba Jobin Yvon

RAA 2013 72 OP10

A portable 1064 nm Raman spectrometer for analysis of cultural heritage items

Alessandro Crivelli,1* Maurizio Aceto,2 Pietro Baraldi,2 Maurizio Bruni,1 Angelo Agostino,4 Gaia Fenoglio4

1 Nordtest s.r.l., Italy, +39 0143 62422, [email protected]. 2 Dipartimento di Scienze e Innovazione Tecnologica (DISIT), Università degli Studi del Piemonte Orientale, Italy; Centro Interdisciplinare per lo Studio e la Conservazione dei Beni Culturali (CenISCo), Università degli Studi del Piemonte Orientale, Italy 3 Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, Modena, Italy 4 Dipartimento di Chimica, Università degli Studi di Torino, Torino, Italy; Nanostructured Interfaces and Surfaces Center of Excellence (NIS), Torino, Italy

The most common drawback when performing Raman analysis is the occurrence of fluorescence emission in the spectra. In several cases, fluorescence is so high that the spectral features of the compounds of interest can hardly, if ever, be identified. Since fluorescence emission is proportional to the energy of the laser source, this phenomenon is particularly effective when UV-visible laser sources are used, such as 244, 488, 514, 532 or 633 nm. NIR sources such as 785 nm lasers are suitable to address this drawback, but an even more suitable solution is that yielded by the availability of a 1064 nm laser source. Raman analysis of several organic substances gives no results when UV-visible sources are used, while it can result in high quality spectra when a 1064 nm source is used. This is a characteristic behaviour of many organic materials of interest in the field of cultural heritage such as parchment [1], paper [2], ivory [3], etc.

Figure 1. Raman spectra of a natural pearl a.) and of a garnet b.) on an XI century manuscript binding from Italy.

1064 nm laser sources are typically used on Fourier Transform Raman spectrometers, usually equipped with liquid nitrogen-cooled detectors. This makes very difficult to design portable Raman systems allowing to perform in situ analysis with 1064 nm source. Only recently instruments equipped with Thermoelectrically cooled detectors have been made available, allowing to reduce the overall dimensions of the systems.

73 Book of Abstracts OP10

The Rigaku XantusTM-1064 Handheld Raman Analyzer is a very compact Raman spectrometer, equipped with a 500 mW laser and a Peltier-cooled high sensitivity array. The spectral resolution is 10 cm-1 calculated as Full Width at Half Maximum (FWHM), while the spectral range is 200-2200 cm-1. It can work with a rechargeable Li ion battery (up to 4 working hours per charge) and its weight is 2.3 kg. All these features make XantusTM-1064 spectrometer highly suitable for in situ measurements, with particular reference to analysis of cultural heritage items which cannot be sampled nor moved outside their natural locations, i.e. museums, libraries, churches or other cultural institutions. Some applications of Raman analysis with XantusTM-1064 spectrometer on artworks will be illustrated in this presentation. Particular concern will be given to gemological analysis (identification of different gemstones, see an example in Figure 1), to analysis of materials of organic or partially organic nature such as parchment or ivory and to analysis of painted artworks such as illuminated manuscripts.

Acknowledgements This work has been financially supported by Nordtest s.r.l.

References [1] H. G. M. Edwards, D. W. Farwell, E. M. Newton, F. Rull Perez, S. Jorge Villar, Spectrochimica Acta A. 2001, 57, 1223. [2] H. G. M. Edwards, D. W. Farwell, D. Webster, Spectrochim. Acta A. 1997, 53, 2383. [3] H. G. M. Edwards, D, W. Farwell, Spectrochimica Acta A. 1995, 51, 2073.

RAA 2013 74 OP11

Novel 1064 nm Dispersive Raman Spectrometer and Raman Micro- scope for Non-invasive Pigment Analysis

Lin Chandler,1*Jack Qian,1 Owen Wu,1 Daniel Thomas2

1 BaySpec, Inc., San Jose, USA, +1 (408)512-5928, [email protected] 2 Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA

Identifying pigments in both art and archeological samples often demands a versatile analytical technique with high specificity and high accuracy, the capacity for direct measurement without sample contact or destruction, and minimal need for sample preparation[1,2]. Raman spectroscopy proves to be by far the most suitable analytical tool that can satisfy these essential criteria, and has proven useful for identifying falsification in, and monitoring the repair of, ancient artwork. Coupled with a microscope, Raman spectrosopy is capable of identifying trace forensic evidence at micron scales [3]. With recent advances in diode lasers and fast array detectors, Raman spectroscopy has improved dra- matically with regards to ease of operation and analysis time, all at steadily lowering costs. These advances have led to widespread use in many fields, including material identification, process control, nanomaterial research and biological sciences. However, high fluorescence backgrounds encountered in colorful samples have limited the use of Raman spectroscopy in pigment analysis. FT-Raman has been the traditional solution for suppressing fluorescent interferences; however, FT-Raman is relatively cumbersome with constant moving parts and long acquisition times. This paper will introduce a new class of 1064 nm dispersive Raman spectrometer with a highly efficient patented VPG grating, fast optics, and a deep-cooled InGaAs detector. The unique three wavelength confocal Raman microscope (532, 785 1064 nm) will be highlighted. Without any moving parts, these compact 1064 Raman spectrometers feature high sensitivity, high spectral resolution, and stability. The built-in battery, remote control via WiFi, and flexible fiber probe accessories make this instrument extremely suitable for field applications. Ultimately, the 1064 Dispersive Raman is the solution for the most complex pigment analysis, and is particularly useful for samples that fluoresce under visible light excitation. This paper

Figure 1. Comparison of 785nm (left) and 1064nm (right) Raman spectra of oil paints in different colors. Superior flurescence avoidence at 1064nm enhanced the Raman features. The spectra were taken by BaySpec’s NomadicTM multi-excitation Raman microscope.

75 Book of Abstracts OP11 will present experimental results obtained from archaeological materials, such as brightly pigmented feathers, and will demonstrate the utility of 1064 nm Raman spectra for material identification.

Acknowledgements DBT is funded by a Peter Buck postdoctoral fellowship from the National Museum of Natural History, Smithsonian Institution.

References [1] P. Vandenabeele, H.G.M. Edwards, L. Moens, Chem Rev. 2007, 107(3), 675–686. [2] A. M. Correia, R. J. H. Clark, M. I. M. Ribeir, M. L. R. Duate, J. Raman Spectrosc. 2007, 38(11), 1390–1405. [3] G. D. Smith, R. J. H. Clark, Studies in Conservation. 2001, supplement 1, 92–106.

RAA 2013 76 Tuesday, September 3

77 Book of Abstracts PL2

Surface-enhanced Raman spectroscopy in Art and Archaeology

Marco Leona1*

1 Department of Scientific Research, The Metropolitan Museum of Art, New York, USA, 1-212-396-5476, [email protected]

Surface-enhanced Raman scattering (SERS) has been the subject of considerable study and substantial application in the field of cultural heritage analysis in the last ten years. The giant enhancement of Raman scattering at atomically rough silver surfaces was first observed – but not recognized as such – in 19741. The surface-enhanced Raman scattering effect was recognized in 1977 [2,3] and ten years after, the technique found its first application in the cultural heritage field4. It took another fifteen years, the introduction of CCD equipped Raman microscopes, and a switch to silver colloids, for SERS to be used again in the analysis of materials of archaeological and artistic interest [5-7], this time with a lasting impact. It could be argued that with the exception of immuno-SERS biomedical assays, the analysis of organic colorants and dyes in cultural heritage material is the principal practical application of SERS today.

Figure 1. Objects investigated with SERS at the Metropolitan Museum of Art: among them archaeological and medieval polychrome sculpture, textiles, drawings and paintings.

Several groups are currently active in SERS research on cultural heritage, and considerable progress has been made in the study of natural dyes, in the development of plasmonic substrates and analytical protocols, and in the application of SERS to actual samples from works of art. A number of misconceived notions have however slowed down the diffusion of SERS: chief among them are the supposed lack of reproducibility of the technique, the difficulty in preparing reliable and stable supports, and the perceived difficulty in searching SERS spectra against a library. While dyes differ widely in their SERS efficiency (a term used here to include both differences in SERS cross-section and the affinity of a dye for a given plasmonic substrate), thus complicating quantitative estimations of dyestuff components and sometimes making it impossible to detect the target analyte over matrix interferences, it can be shown that SERS is otherwise reliable and reproducible, and that SERS spectra can easily be compared with appropriate library references. At the Metropolitan Museum of Art, SERS has been used to identify organic dyes in samples from over one hundred works of art, ranging in dates from 2000 BC to the present. The range of dyes studied and identified in works of art includes madder, kermes, lac, cochineal, methyl violet, nile blue and eosine, from Ancient Egypt to the Impressionists and to Contemporary Art. In addition, almost all natural dyes have been characterized by SERS, although some important classes, such as the flavonoids, remain difficult to identify in micro-samples from ancient objects.

RAA 2013 78 PL2

While several plasmonic substrates and sample treatment approaches have been employed in the study of dyes and colorants, we have found the use of resonant excitation, a stable and highly efficient silver colloid [8], and a two-step measurement approach (analysis of the sample as-is, followed by recovery of the sample and a second analysis after a lossless non-extractive hydrolysis sample treatment) [9] to give the best results. Spectra thus obtained can be reliably compared with reference spectra, and searched against a SERS spectral library containing over one hundred spectra representing different dyes measured in different conditions, using the Correlation Coefficient approach or Principal Component Analysis. Microwave assisted reduction of silver sulfate in the presence of glucose and sodium citrate results in a stable mono-disperse colloid. (Figure 2, left panel).

Figure 2. Left panel: optical absorption spectra of aliquots of the same Ag colloid, sampled n days after synthesis. Right panel: a.) SERS spectrum of reference madder lake upon HF treatment compared to those of a red glaze from Cézanne’s The card players b.) on Ag microwave colloid upon HF treatment and c.) on 5x Ag microwave colloid without hydrolysis. Marked with * are spurious bands due to the colloid.

Sample treatment prior to analysis adds versatility to SERS. HF vapor hydrolysis for textile and glaze samples enhances sensitivity to the point where samples down to 20 µm can be analyzed. EDTA/DMF treatment coupled with gel mediated solid phase micro-extraction can be used for quasi non-invasive analysis.

References [1] M. P. Fleischmann, J. Hendra, A. J. McQuillan, Chem. Phys. Lett. 1974, 26, 163–166. [2] D. L. L. Jeanmaire, R. P. Van Duyne, J. Electroanal. Chem. Interfacial Electrochem. 1977, 84, 1–20. [3] M. G. Albrecht, J. A. Creighton, J. Am. Chem. Soc. 1977, 99, 5215–5217. [4] B. Guineau, V. Guichard, ICOM Committee for Conservation: 8th triennial meeting, Sydney, Australia, 6–11 September, 1987. Preprints, The Getty Conservation Institute: Marina del Rey, Sydney, Australia, 1987, 2, 659-666. [5] I. T. Shadi, B. Z. Chowdhry, M. J. Snowden, R. Withnall, J. Raman Spectrosc. 2004, 35, 800-807. [6] M. V. Cañamares, J. V. Garcia-Ramos, C. Domingo, S. Sanchez-Cortes, J. Raman Spectrosc. 2004, 35, 921–927. [7] M. Leona, 6th IRUG Meeting, Florence, March 29–April 1, 2004. Proceedings, Il Prato, Padova, 2005, 105–112. [8] M. Leona, PNAS. 2009, 106 (35), 14757. [9] F. Pozzi, J. R. Lombardi, S. Bruni, M. Leona, Anal. Chem. 2012, 84 (8), 3751.

79 Book of Abstracts OP12

TLC-SERS of mauve, the first synthetic dye

Maria Vega Cañamares,1,3* David A. Reagan,2 Marco Leona3

1 Instituto de Estructura de la Materia, IEM-CSIC, Madrid, Spain, +34915616800, [email protected] 2 Southern Connecticut State University, New Haven, Connecticut, [email protected] 3 Metropolitan Museum of Art, New York, +12123965476, [email protected]

Mauveine was the first synthetic organic dyestuff to be manufactured industrially. William Henry Per- kin discovered this purple dye by chance when trying to synthesize quinine, the only known remedy for malaria. He obtained a purple solution which he then used to colour silk. Up to then, most dyes were natural compounds extracted from plants and animals. Perkin’s synthesis of mauve and the establishment of a factory to in 1862 to produce it commercially mark the beginnings of the modern dye indus- try.[1] The main components of mauveine are mauveine A and B; other components such as mauveine B2 and C were also discovered in 2007.[2]

In this study we endeavoured to synthesize mauveine and to obtain its Raman spectrum, using ordinary dispersive Raman spectroscopy, Fourier-Transfrom Raman, and Surface-enhanced Raman Scat- tering (SERS). These techniques are all well established for the analysis of artists’ pigments and dyes.[3] In addition to measurements on the dye as synthesized we also attempted measurements on fractions separated by Thin Layer Chroamtography (TLC).

The coupling of Thin Layer Chromatography (TLC) with Raman/SERS spectroscopy represents an interesting technique for the Raman analysis of mixtures. Coupling of TLC and SERS was first reported by Henzel in 1977.[4] However, the use of this technique for the study of dyes is quite recent.[5,6] Here we demonstrate its utility in the case of a highly fluorescent complex synthetic dye.

The synthesis of the dye was performed following Perkins’ original recipe as modified by Scaccia.[7] The separation process was carried out by thin layer chromatography (TLC) utilizing a solution of isobu- tanol, acetic acid, and ethyl acetate. The samples were deposited onto a silica gel TLC plate and eluted in a glass developing chamber. Dispersive Raman and SERS spectra were recorded in a Bruker Senterra Raman spectrometer equipped with a long working distance microscope objective and a charge-coupled device detector. The 633 and 785 nm laser lines were employed to register the ordinary Raman spectra. FT-Raman spectra were acquired with a Bruker RamII Vertex 70 spectrometer equipped with a liquid nitrogen cooled Ge detector. The 1064-nm line provided by a Nd:YAG laser was used for excitation. Ag nanoparticles prepared by reduction with trisodium citrate[8] were used as SERS substrates. Different aggregating agents were tested. For the TLC-SERS analysis, the samples were prepared by placing a small amount of aggregated silver nanoparticles directly on the spot of separated each component.

No satisfactory ordinary Raman or FT-Raman spectra of mauve were obtained. This was due in the case of ordinary dispersive Raman to the high fluorescence of the dye, and in the case of FT-Raman to its high absorption of the Near IR radiation, leading to thermal damage before a spectrum could be obtained. SERS however gave excellent spectra: the most intense SERS spectra were registered under excitation at 633 nm and acidic conditions.

RAA 2013 80 OP12

Five different components of mauveine were separated by TLC: a light red spot at Rf = 0.32 and four purple spots at Rf values of 0.56, 0.63, 0.70, and 0.78. No spectrum was obtained by direct Raman analysis due to the low concentration of the dye in each analysed spot. On the contrary, intense SERS spectra of each component were obtained. No interfering fluorescence was observed in the spectra of the four purple spots (Figure 1). Band positions between the spectra only differed slightly from each other, with only a few bands being unique for each component. Most bands also had similar intensities. The spectra for spots at R f = 0.70 and 0.78 were particularly related, both having, for instance, in- -1 tense bands around 1017 cm . Spots at Rf = 0.56 and 0.63 were also closely related, the bands around 1017 cm-1 being less intense than the corresponding bands in the other two spots. To conclude, satisfactory Raman spectra of mauveine and its different components could be only obtained by the application of SERS spectroscopy. The main difficulty in the analysis of mauve by ordinary Raman spectroscopy was the intense fluorescent emission of the sample. By using SERS however we were successful not only in recording a spectrum of the complex dye, but also in obtaining spectra of each individual component of the dye mixture directly on a TLC plate.

Figure 1. SERS spectra of the four purple compounds separated by TLC.

References [1] P. Ball, Nature. 2006, 440, 429. [2] J. S. De Melo, S. Takato, M. Sousa, M. J. Melo, A. J. Parola. Chemical Communications. 2007, 2624–2626. [3] M. V. Cañamares, M. Leona, M. Bouchard, C. M. Grzywacz, J. Wouters, K. Trentelman, J. of Raman Spectrosc. 2010, 41, 391–397. [4] U. B. Henzel, C. Zeis, J. of Chromatography Library. 1977, 9, 147–188. [5] C. L. Brosseau, A. Gambardella, F. Casadio, C. M. Grzywacz, J. Wouters, R. P. Van Duyne. Analytical Chemistry. 2009, 81, 3056-3062. [6] F. Pozzi, N. Shibayama, M. Leona, J. R. Lombardi. J. of Raman Spectrosc. 2013, 44, 102–107. [7] R. L. Scaccia, D. Coughlin, D. W. Ball, J. of Chemical Education. 1998, 75, 769. [8] P. C. Lee, D. Meisel, J. of Physical Chemistry. 1982, 86, 3391–3395.

81 Book of Abstracts OP13

New photoreduced substrate for SERS analysis of organic colorants

Klara Retko,1* Polonca Ropret,1,2 Romana Cerc Korošec3

1 Research Institute, Conservation Centre, Institute for the Protection of Cultural Heritage of Slovenia, Ljubljana, Slovenia, +38612343118, [email protected], [email protected] 2 Museum Conservation Institute, Smithsonian Institution, Suitland, Maryland, USA 3 University of Ljubljana, Faculty of Chemistry and Chemical Technology, Ljubljana, Slovenia, +38612419136, [email protected]

In the last decades, the interest has emerged for the development of sensitive and selective techniques that are effective for the detection of organic dyestuffs used as artists’ materials. One of the prospective techniques is also Surface Enhanced Raman Spectroscopy (SERS), as it overcomes the weak Raman activity of the organic pigments and dyes, in addition to fluorescence quenching.[1–3] The signal enhancement depends strongly on the quality of the SERS-active substrate[4], with its reproducibility being the main challenge of the technique. For that purpose, the described research focused towards the synthesis of a stable and reproducible substrate of high viscosity. New UV- photoreduced substrate, using hydroxypropyl cellulose as the stabiliser and silver nitrate as the initial substance, is suggested. Substrates’ characteristics were examined by absorption spectroscopy (UV-Vis), electron microscopy (FE-SEM) and Raman spectroscopy. It was established that the substrate stayed stable for several months and that the aggregation of silver nanoparticles is induced spontaneously with no need of adding any aggregation agent. Moreover, substrate alone shows a weak Raman activity, causing less interference in spectra for further interpretation. The properties of the new substrate were compared among some other known substrates and also tested with alizarin as a model substance (Figure 1). The obtained Raman band positions of alizarin were in a good agreement with previously reported data.[5]

Figure 1. Comparison of a.) Raman spectrum and b.) SERS spectrum of alizarin. UV-photoreduced substrate was employed for the SERS analysis, the bands typical of alizarin were determined. In the latter spectrum, the Raman signal is amplified above the fluorescence signal.

RAA 2013 82 OP13

Furthermore, the substrate enabled the detection of organic colorants in colour layers. Although they were prepared with different organic binders (also potential source of SERS signal), it was almost exclusively the organic colorants which exhibited higher signal enhancements. It is possible to conclude, that other organic components in binders have a weaker affinity to silver nanoparticles in the substrate, thus producing insufficient signal for possible overlapping with the Raman bands of interest. It is worth mentioning that no pre-treatment of the samples was needed prior to the analysis. The research was extended to the examination of a glaze made of organic dye on a cross section taken from a mock panel. Owing to the increased viscosity of the substrate, it was possible to exert a better control of the application, compared to other tested substrates of lower viscosity. A capillary (application under the microscope, drop diameter approximately 200 µm) was used to focus the substrate above a specific layer (the area of interest) (Figure 2a), and the spectrum was recorded (Figure 2b) from the interface between the substrate drop and the paint layer of interest. Therefore, the precipitation of the silver onto the larger part of the sample (contamination) was avoided. Despite the low thickness (below 10 mm) of the investigated layer and low concentration of the organic dye, the detection was successful. On the basis of this study, the advantages of the new photoreduced substrate are attributed especially to SERS-activity, stability and viscosity.

Figure 2. a) A photomicrograph of a cross section presenting glaze containing an organic dye (marked with an arrow). b) SERS spectrum obtained on the glaze layer, identifying organic dye Alizarin Carmine (Alizarin Red S).

References [1] M. Leona, J. Stenger, E. Ferloni, J. Raman. Spectrosc. 2006, 37, 981. [2] C.L. Brosseau, K.S. Rayner, F. Casadio, C. M. Grzywacz, R. P. Van Duyne, Anal. Chem. 2009, 81, 7443. [3] F. Casadio, M. Leona, J. R. Lombardi, R. P. Van Duyne, Acc. Chem. Res. 2010, 43, 782. [4] M. V. Cañamares, J. V. Garcia-Ramos, J. D. Gomez-Varga, C. Domingo, S. Sanchez-Cortes, Langmuir 2005, 21, 8546. [5] M. V. Cañamares, J. V. Garcia-Ramos, C. Domingo, S. Sanchez-Cortes, J. Raman. Spectrosc. 2004, 35, 921.

83 Book of Abstracts OP14

Laser Ablation Surface-enhanced Raman Microspectroscopy

Pablo S. Londero,1* John R. Lombardi,2 and Marco Leona3

1 Department of Scientific Research, The Metropolitan Museum of Art, New York, [email protected] 2 Department of Chemistry, The City College of New York, New York 3 Department of Scientific Research, The Metropolitan Museum of Art, New York

While Surface-enhanced Raman scattering (SERS) has proved to be a valuable technique for the analysis of art objects,[1–3] a number of factor have limited the breadth of its applicability. Arguably two of the greatest are robust methods for adsorbing the analyte onto the SERS-active substrate, and for achieving microscopic spatial resolution. One technique that is capable of achieving such resolution is tip-enhanced Raman spectroscopy,[4] but here also the breadth of applications has been limited by the specific sample preparation required for optimal performance. What is needed, then, is a robust method for SERS analysis with a high degree of spatial specificity. Here we demonstrate a sample-independent approach to SERS analysis that requires no solvent, has sensitivity approaching that of mass spectrometry, and also has spatial resolution as low as 5 _m. By integrating laser ablation micro-sampling with efficient close-proximity collection of the ablated molecules on an optimized SERS-active surface, we show that vibrational information can be easily acquired with microscopic spatial resolution and with detection limits approaching that of mass spectrometry. The instrument and procedure are illustrated in Figure 1. The Raman microspectrometer, equipped with a tunable Optical Parametric Oscillator (OPO) source, has been previously described in the literature.[5] The sample is placed in a small vacuum chamber, on a vertically translating platform. The quartz window on the top of the chamber is coated on the vacuum side with a 10 nm thick layer of silver nanoislands that functions as the SERS-active substrate. The window is placed silver-side down, 300 μm from the sample surface. The chamber is sealed a turbo pump is used to lower the internal pressure to less than 10-4 mTorr. To perform a measurement, the OPO is tuned to the choromophore resonance and a single 7 ns pulse with an energy of 1-100 μJ is typical. Molecules ablated onto the nanoisland film are then optically excited using a continuous 488 nm ‘read’ laser, typically with a 20X objective at powers of 0.1 mW. The SERS spectrum is collected in the backward propagating direction by the same objective, and directed into the spectrometer. This approach, with significant room for improvement, achieves benchmarks approaching those of some mass-spectrometry techniques with the addition of vibrational information: we’ve observed spatial resolution of a few micrometers and sub-picogram sensitivity. As a demonstration of the robusteness, sensitivity and spatial resolution achievable, we performed ablation-SERS on a film of the water/alcohol-insoluble pigment copper phthalocyanine (CuPc). Several other pigment samples have also been tested. The CuPc sample was evaporated onto a glass coverslip. The prominent 1526 11 cm-1 B1g mode was chosen as the marker for the compound (see Fig. 2a). An ablated crater of diameter of ~5 μm, shown in Fig. 2a, deposited sample over a diameter of 310 μm on the Ag nanoisland film, as measured by the FWHM of the signal intensity. The crater contour was characterized by Figure 1. Apparatus and measurement sequence for atomic force microscopy, and corresponds to 42 pg of ablated ablation-based SERS. material.

RAA 2013 84 OP14

The SERS signal of CuPc was detected using 0.3 mW of laser power with an integration time of 30s and a 1/e2 spot size of 4 μm. The results are shown in Fig. 2b. After ablation, several characteristic sharp peaks were observed. Using a high-pass Fourier filter to remove broad background we observed a spectral signature with a signal-to noise ratio (SNR) of 5:1. One can, however, integrate signal for much longer periods of time from the same ablated sample. In practice we find that linear photodamage from the 488 nm laser is the ultimate limitation to the counting time. In the case of CuPc the signal decays a SNR of 1:1 in 600 minutes, which results in an instrument limit-of-detection of only 70 fg or 120 attomoles, approaching that of some mass-spectrometry instrumentation.[4,5] A number of straightforward future improvements could raise sensitivity by more than 100X, such as increasing the detection laser spot size on the Ag nanoisland film or applying a more sensitive SERS-active film.

Figure 2. a.) Fourier-filtered SERS spectrum of CuPc film resulting from a 5 μm ablation spot. b.) SERS spectrum from ablated sample of dyed ancient Egyptian leather, with matching reference spectrum for Madder Lake.

As a direct application, we have used ablation-SERS to characterize the colorant in a fragment of dyed leather from the trappings of an ancient Egyptian chariot. As the colorant was thought to be a complex of an anthraquinone dye with a polyvalent cation (most likely aluminium), a microscopic sample was removed, and briefly exposed to hydrofluoric acid vapors in a microchamber. This step has the effect of hydrolyzing the colorant producing the free anthraquinone, a more volatile species, thus increasing sensitivity.[8] Without the hydrolizing treatment, no spectrum was observed. The results are shown in Figure 2c. A strong signal of the dye madder was detected, as can be seen by comparison to the reference sample. This example clearly shows the applicability of ablation SERS to real-world, complex samples. This technique has the potential to significantly increase our ability to study modern and ancient complex samples by SERS. It is a robust and highly sensitive tool for the detection of small-molecule analytes that can be applied regardless of solubility with excellent spatial resolution and sensitivity comparable to mass spectrometry techniques.

Acknowledgements We are indebted to the National Science Foundation (CHE-1041832) for funding of this project.

References [1] M. Cañamares, J. Garcia-Ramos, C. Domingo, S. Sanchez-Cortes, J. Raman Spectrosc. 2004, 35: 921. [2] M. Leona, J. Stenger, E. Ferloni, J. Raman Spec. 2006, 37: 981-992. [3] K. Wustholz, C. Brosseau, F. Casadio, R. Van Duyne, Phys. Chem. Chem. Phys. 2009, 11: 7350-7359. [4] R. M. Stockle, Y. D. Suh, V. Deckert, R. Zenobi, Chem. Phys. Lett. 2000, 318: 131-136. [5] P. Londero, M. Leona, J. R. Lombardi, DOI: 10.1002/jrs.4150. Published online: Aug 8, 2012. [6] T. Sikanen, S. Tuomikoski, R. A. Ketola, R. Kostiainen, S. Franssila, T. Kotiaho, Anal. Chem. 2009; 79: 9134–9144. [7] L. Alder, K. Greulich, G. Kempe, B. Vieth, Mass. Spec. Rev. 2006, 25: 838-865. [8] F. Pozzi, J. R. Lombardi, S. Bruni, M. Leona, Anal. Chem. 2012, 84: 3751-3757.

85 Book of Abstracts OP15

Silver colloidal pastes for the analysis via Surface Enhanced Raman Scattering of colored historical textile fibers: some morphological and spectroscopic considerations

Ambra Idone,1,2* Monica Gulmini,3 Francesca Casadio,4 Lisa Backus,4 Lauren Chang,4 Lorenzo Appolonia,2 Richard P. Van Duyne,5 Nilam Shah5

1 Università degli Studi del Piemonte Orientale “A. Avogadro”, Dipartimento di Scienze e Innovazione Tecnologica, Italy, +39 0131 360265, [email protected] 2 Regione Autonoma Valle d’Aosta, Direzione Ricerca e Progetti Cofinanziati, Laboratorio Analisi Scientifiche, Villair di Quart (AO), Italy, +39 0165771700, [email protected] 3 Università degli Studi di Torino, Dipartimento di Chimica, Torino, Italy, +39 011 6705265, [email protected] 4 The Art Institute of Chicago, Illinois, US, +1 312 8577647, [email protected] 5 Department of Chemistry, Northwestern University, Evanston, Illinois, USA, +1 847 4912952, [email protected]

In recent years Surface Enhanced Raman Spectroscopy (SERS) has become a valid tool to investigate organic colorants in samples of historical and artistic significance and offers now new analytical strategies for scientific investigation in the field of art history and conservation.[1] The noble metal substrate effectively overcomes problems affecting normal Raman spectroscopy, such as high fluorescence due to the complex chemical environment and lack of signal due to very low concentrations of the molecules under investigation. The main challenge in performing dye analysis with SERS is the feasibility of delivering suitable SERS substrates directly on the sample, in order to avoid further treatments of the sample itself and to minimize down to a micro-scale the fragments that have to be detached from the artwork. A variety of SERS substrates have been proposed for art analysis including metal films over nanospheres (FONs),[2,3] concentrated silver colloids[4] and nanoparticles obtained by in-situ photo-reduction[5] or laser ablation.[6] Among them, chemically reduced silver colloids are presently the most popular substrates for SERS in art analysis. The present work reports the results of a thorough investigation of silver colloids[7] that are concentrated according to Brosseau et al.[4] (henceforth SC pastes) for analysis of different types of natural fibers dyed red with brazilwood or cochineal. The morphological, physical and optical characteristics of the SC paste are investigated and discussed. Specifically, the SC paste is tested on modern wool and silk dyed with cochineal or brazilwood, as well as on cotton and flax tinted with brazilwood, at various concentrations. Moreover, historical textiles from an important collection of Mariano Fortuny (1871–1949) textiles at the Art Institute of Chicago are examined, in order to test the efficacy of the SC paste on aged samples, and to shed light on whether it is true that, at a time when the chemical industries were flooding the market with bright and attractive new industrial products, Fortuny did not use synthetic dyes. Scanning electron microscopy is employed to highlight the morphological characteristics of the paste itself and to image the coatings that develop when the paste is spread on the various fibers. Spherical nanoparticles (30 to 100 nanometers in diameter) with a minority of rod-shaped particles (50 to 200 nm in length) are observed. SEM images show that the hydrophobic nature of the wool fiber’s surface limits the coverage of the silver coating, whereas the highly hydrophilic vegetal fibers are almost completely covered. Despite the

RAA 2013 86 OP15 different extent of coverage of the silver coating, areas with a homogenous layer of nanoparticles that is SERS active were observed in all the considered reference samples. The SC paste was effective in enhancing the signals of the dyeing molecules of cochineal and brazilwood, although finding SERS activity was somewhat harder when analyzing wool fibers with respect to other fibers. Besides the presence of spurious signals from the SC paste itself, the spectra obtained from reference samples did not show additional peaks that can be attributed to the proteinaceous or glycosidic fibers. Regarding the historical samples, the use of natural colorants was confirmed in the Fortuny fiber samples that were analyzed. Cochineal and brazilwood were found in both the silk velvets and cotton fibers examined, testifying that a skillful combination of such dyes (here identified simultaneously on the same fiber with direct extractionless SERS with SC pastes) was put in place to obtain a variety of different hues contributing to the enduring allure of such beautiful textiles.

Acknowledgements This work was carried out with the contribution of European Union, of the Regione Autonoma Valle d’Aosta and of the Italian Ministry of Labour and Social Policy. Support from the Andrew W. Mellon Foundation and the National Science Foundation through grants CHE-0414554, CHE-0911145, and DMR-1121262 is also gratefully acknowledged. The RET program at Northwestern University, sponsored by the Materials Research Science and Engineering Center under NSF grant DMR 0520513, and its director, Prof. Monica Olvera de la Cruz are also gratefully acknowledged. The SEM work was performed in the EPIC and facility of NUANCE Center at Northwestern University. NUANCE Center is supported by NSF-NSEC,NSF-MRSEC, Keck Foundation, the State of Illinois, and Northwestern University. Anne-Isabelle Henry is thanked for SEM imaging.

References [1] F. Casadio, M. Leona, J. R. Lombardi, R. Van Duyne, Accounts Chem. Res. 2010, 43, 782. [2] A. V. Whitney, F. Casadio, R. P. Van Duyne, Appl. Spectrosc. 2007, 61, 994. [3] N.G. Greeneltch, A. S. Davis, N. A. Valley, F. Casadio, G. C. Schatz, R. P. Van Duyne, N. C. Shah, J. Phys. Chem. A 2012, 116, 11863. [4] C. L. Brosseau, A. Gambardella, F. Casadio, C. M. Grzywacz, J. Wouters, R. P. Van Duyne, Anal. Chem. 2009, 81, 3056. [5] Z. Jurasekova, C. Domingo, J. V. Garcia-Ramos, S. Sanchez-Cortes, J. Raman Spectrosc. 2008, 39, 1309. [6] M.V. Cañamares, J. V. Garcia-Ramos, S. Sanchez-Cortes, M. Castillejo, M. Oujja, J. Colloid Interf. Sci. 2008. 326, 103. [7] P. C. Lee, D. Meisel, J. Phys. Chem. 1982, 86, 3391.

87 Book of Abstracts OP16

Surface enhanced Raman spectroscopy for dyes and pigments – Can non-invasive investigations become a reality?

Brenda Doherty,1* Brunetto Giovanni Brunetti,2,3 Antonio Sgamellotti,2,3 Costanza Miliani1

1 Istituto CNR di Scienze e Tecnologie Molecolari (ISTM), Dipartimento di Chimica, Università degli Studi di Perugia, Italy, +39 075 5855638, [email protected], [email protected] 2 SMAArt c/o Dipartimento di Chimica, Università degli Studi di Perugia, Italy 3 Università degli Studi di Perugia, Italy

Surface enhanced Raman spectroscopy in the cultural heritage field is still a relatively new technique that is progressing in its application for the sensitive and selective detection of natural and synthetic organic dyes and pigments. Proposed working methods and protocols by leading groups in this field differ in both active surface preparation and sample pre-treatments. The most commonly adapted SERS active substrate preparations range from solid state substrates, and variably reduced and stabi- lized silver colloids [1]. Sample preparations instead range from no preparation whatsoever, to various extraction and hydrolysis methods often employed to liberate the dye from its pigment complex. All of the highlighted procedures however, have a common important aim, that is, to identify and characterize the organic colorant/pigment according to accurately compiled in-house databases through the simultaneous amplification of Raman scattering and fluorescence quenching accounted for by the electromagnetic and chemical mechanisms. Furthermore, all usable methods are increasingly tailored towards the many heterogeneous and complex matrices where the dyes and pigments are collocated including paint films, textiles and paper so as maximise the efficiency and ease of implementation of the SERS protocol for a practical, systematic and reliable use. Research conducted in the early 2000s introduced the idea of disposable SERS films by employing a hydrophilic polymer gel [2]. Regarding dyes and pigments in the cultural heritage field in tapestries and Japanese prints [3], implemented a cross linked hydroxyacrylate gel combined with a solvent and chelating agent for minimum extraction directly from the artwork followed by SERS analyses. Research in our laboratory 2011 evidenced a silver colloid doping of methylcellulose for a removable SERS active gel following measurements on painting lakes [4]. Since then, work by [5], has suggested a doped agar SERS active matrix to be applied to textiles.

Figure 1. SERS spectra of nanocomposite methylcellulose in function with gel viscosity on a triarylmethane standard.

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This contribution focalizes principally on the optimization of the proposed nanocomposite methylcellulose gel for its use in a non-invasive capacity. It is shown that glucose reduced silver colloids doped into different viscous grades of methylcellulose permits for an improvement of achieved SERS enhancement as well as a contemporary mechanical improvement enabling a more even gel removal rende- ring this an adapt SERS substrate as tested by standard synthetic dyes (Figure 1). Regarding the investigation of pigment lakes, the additional effects of hydrolysis have been approached so as to evaluate the compromised non-invasive nature over relative enhancements afforded by the gel so as to arrive to a protocol for its effective use. Furthermore, it is shown that the same colloid has shown promise when doped into a further natural gel for the creation of a removable film for use on a paper matrix (Figure 2). All studies have been effectuated utilizing a bench top Raman spectrophotometer and portable Raman instrumentation for movement towards in-situ applications.

Figure 2. Image of a.) a 1mm diameter doped gel on a synthetic dye on paper and b.) the same gel following SERS measurements and subsequent total removal.

References [1] F. Casadio, M. Leona, J. R. Lombardi, R. V. Duyne, Accounts of Chemical Research. 2010, 43, 782–791. [2] S. E. J. Bell, S. J. Spence, Analyst. 2001, 126, 1–3. [3] M. Leona, U.S. Patent No. 7, 362,431 (9 August 2006). [4] B. Doherty, B. G. Brunetti, A. Sgamellotti, C. Miliani, J. of Raman Spectrosc. 2011. 42, 1932–1938. [5] C. Lofrumento, M. Ricci, E. Platania, M. Becucci, E. Castellucci, J. of Raman Spectrosc. 2013. 44, 47–54.

89 Book of Abstracts OP17

Surface Enhanced Raman Scattering of organic dyes on noble metal substrates prepared by pulsed laser ablation

N. R. Agarwal,1,2* M. Tommasini,2 P. M. Ossi,3 E. Fazio,4 F. Neri,4 S. Trusso,5 R.C. Ponterio5

1 Nanostructures, Istituto Italiano di Tecnologia, Genova, Italy, [email protected] 2 Dipartimento di Chimica, Materiali e Ingegneria Chimica ‘Giulio Natta’, Politecnico di Milano, Milan, Italy. 3 Dipartimento di Energia and Centre for Nano Engineered Materials and Surfaces, NEMAS, Politecnico di Milano, Milan, Italy 4 Dipartimento di Fisica e di Scienze della Terra, Università di Messina,V.le Ferdinando Stagno d’Alcontres 31, 98166, Messina, Italy 5 CNR-IPCF, Istituto per i Processi Chimico-Fisici, Messina, Italy

Raman spectroscopy is a valuable technique for detecting and characterizing dyes used in ancient times and helps to assess the geographic origin or dating of artworks. Yet, the Raman spectra of most of such dyes present a strong fluorescence background or a very low Raman scattering cross section that prevent the acquisition of well-resolved data, which could be useful as a fingerprint for dye identification. Surface-enhanced Raman scattering (SERS) can be used to overcome such drawbacks, in fact, Raman cross sections of molecules adsorbed on artificially roughened noble metal surfaces show dramatic enhancements as a consequence of the strong amplification of the incident field produced by the excitation of the localized plasmon resonance modes corresponding to the metallic nanostructure. Nevertheless, caution should be taken in the identification of SERS spectra of substances. Their interaction with the metal substrate can result in a drastic modification of the Raman spectrum: Raman inactive modes can become active, relative intensities between different modes can be altered and also measurable frequency shift of some vibration modes can be observed. Furthermore, some analytes can undergo chemical reactions at the metal surface also resulting in drastic changes of the Raman spectra. Here, we present a study of the SERS behaviour of two dyes of interest in the cultural heritage field: alizarin and purpurin adsorbed on noble metal nanostructured substrates. Their molecular structures differ by the presence of an additional hydroxy group in purpurin. Normal Raman measurements allow distinguishing the two molecules in the high concentration regime, which is a rare condition for application in artwork analysis. However, identification from SERS measurements may not be easy due to adsorption mechanism on the substrate together with the presence of different chemical isomers that can play a role in SERS. In order to investigate this point we performed both SERS measurements and DFT calculations. Active Ag and Au nanostructured thin films were grown by pulsed laser ablation in a controlled argon atmosphere. The growth mechanism was studied in detail in previous works. [1–3] The control of the surface morphology was achieved by changing the argon pressure and the laser shots number. All the other relevant deposition parameters like fluence, target to substrates distance and substrates temperature were kept fixed. This allowed the optimization of the SERS activity as evidenced by measurements performed using Rhodamine 6G as a test molecule.[4] Au films were grown in presence of 70 Pa of Ar, at the laser fluence of 1.8 Jcm-2 and with 10000 laser shots. Surface morphologies (Fig.1) were studied by scanning electron microscopy (SEM). The surface is characterized by the presence of irregularly shaped islands built by nanoparticles grown during the plasma expansion as a consequence of the collisions between the plasma and the gas species. Substrates were soaked into water solutions of pure alizarin and purpurin at different concentration levels

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(between 10–3 and 10–5 M). Micro Raman measurements were carried out using 1064 nm and 632.8 nm wavelength. SERS spectra were acquired after soaking the gold substrates into the solutions for 1h then rinsed with deionized water and left to dry in air. Clear spectra of both molecules were recorded on the substrates. Moreover, the homogeneity of the substrates was checked by performing measurements on surface area of about 60x60 _m2. DFT calculations were performed on different chemical isomers of alizarin and purpurin due to the effect of tautomerism. The simulated Raman spectra for these tautomers are different from each other due to the transfer of a proton from one part of the molecule to the other which affects the π conjugation within the molecule core. None of the computed Raman spectra correctly define the experimental Raman spectra since all the tautomers play equivalent role for obtaining Raman. Statistical analysis on mapping of more than 100 SERS spectra was carried out to extract useful information and compare it with DFT calculations in order to establish the role of different tautomeric forms.

Figure 1. SEM image of the surface morphology of SERS active gold substrate grown by PLD.

References [1] P. M. Ossi, A. Bailini, Appl. Phys. A, 2008, 93, 645. [2] E. Fazio, F. Neri, P. M. Ossi, N. Santo, S. Trusso, Appl. Surf. Sci. 2009, 255, 9676. [3] C. D’Andrea, F. Neri, P. M. Ossi, N. Santo, S. Trusso, Nanotechnology 20, 2009, 245–606. [4] N. R. Agarwal, F. Neri, S. Trusso, A. Lucotti, P. M. Ossi, Appl. Surf. Sci. 2012, 258, 9148.

91 Book of Abstracts OP18

Combining SERS with chemometrics: a promising technique to assess historical samples with historically accurate reconstructions

Rita Castro,1,2* Maria J. Melo,1,2 Federica Pozzi,3 Marco Leona,3 João Lopes4

1 Departamento de Conservação e Restauro, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus Caparica, Portugal, [email protected] 2 REQUIMTE-CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus Caparica, Portugal 3 Department of Scientific Research, The Metropolitan Museum of Art, New York, USA 4 REQUIMTE, Laboratório de Química Analítica e Físico-Química, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal

In this work a multi-analytical approach was conducted to characterize several dark red organic microsamples removed from illuminations of 9 manuscripts from three of the most important monasteries in Portugal: Lorvão, Alcobaça and Santa Cruz, dating from the 12th and 13th centuries. [1] In order to achieve a full characterisation, the samples were analysed by micro X-ray fluorescence (μ-EDXRF), infrared spectroscopy (μ-FTIR), Raman spectroscopy, microspectrofluorimetry[2] and ultimately Surface-Enhanced Raman spectroscopy (SERS) with chemometrics.

After having identified lac dye by μ-FTIR in selected micro-samples, several lac dye recipes from medieval treatises were reproduced. The recipes used for these historically accurate reconstructions were taken from the following sources: Ibn Bādīs ms. (an Arabic manuscript from ca. 1025), Mappae Clavicula (8-12th centuries), O libro de komo se fazen as kores (a Portuguese treatise from the 15th century), Bolognese ms. (15th century) and Strassburg ms. (15th century). Two main preparation methods are distinguished in these treatises: the ones that are prepared without a metal cation (i.e. mordant); and the ones that formulate an organo-metallic complex, to form a lake pigment. These reproductions were also fully characterized by infrared spectroscopy and microspectrofluorimetry. The latter revealed to be promising and the results obtained for the original samples were further confirmed by SERS. SERS is becoming a valuable procedure for the identification of dyes in microscopic samples. The experimental procedure was applied to the historical samples and the reconstructions with Ag colloid obtained by microwave supported reduction of silver sulfate[3] The spectra were obtained with or without hydrofluoric acid (HF) hydrolysis, for non-complexed dyes and dye-metal complex, respectively. In the case of historical samples a two-step procedure was conducted (since the type of sample was unknown), by analyzing the sample first without hydrolysis, and then, after washing the sample, upon HF treatment[4]

By using this technique it was possible to confirm that the dark red used in Portuguese Romanesque illuminations was based on lac dye - at the time a luxury colorant commercialized within the Arab mercantile network. Most of the micro-samples averaged 40 μm in diameter; in some cases it was possible to use up to 20 μm, making this procedure particularly advantageous for illuminated manuscripts.

To explore the information obtained in the Raman spectra, in particular if it could carry details on the process used to prepare the pigment, a chemometrics approach was followed, by applying principal component analysis (PCA) and hierarchical clustering analysis (HCA). PCA allowed us to distinguish

RAA 2013 92 OP18 sample treatment conditions and pH variations. The spectra reproductions were also analysed by HCA, enabling a clear separation of pHs of the non-complexed lac dyes. That did not happen as clearly for the lakes that were submitted to the HF pre-treatment, due to the application of the HF. This was the first time that lac dye was unequivocally identified in a medieval illumination, and it is possible to state that its conservation condition is usually good. It is also important to refer that its colour ranges from dark red, to violet or brownish shades. The historically accurate reconstructions enable us to propose that these shades may be the result of the processing of the colorant and not of degradation. The importance of these findings / results for the history and cultural importance of medieval illuminations will be discussed.

Figures 1, 2. De Avibus (Book of Birds), from the Lorvão monastery (1183-1184), f.6.; SERS spectra of a lac reproduction (grey line) compared to a microsample from Lorvão 5 f.6 on Ag microwave colloid upon HF treatment (black line), and on regular Ag microwave colloid without hydrolysis (black dash line). Marked with * are spurious bands due to the colloid.

Acknowledgements This work has been financially supported by the national funds of FCT-MCTES, through a PhD grant (SFRH/BD/76789/2011) and project “Colour in medieval illuminated manuscripts: between beauty and meaning”, PTDC/EAT-EAT/104930/2008. The authors would also like to thank the staff and directory board of Arquivo Nacional da Torre do Tombo (ANTT), Biblioteca Nacional de Portugal (BNP) and Biblioteca Pública Municipal do Porto (BPMP) for their generous support and collaboration.

References [1] M. J. Melo, A. Miranda, C. Miguel, R. Castro, A. Lemos, S. F. Muralha, J. A. Lopes, A. P. Gonçalves, Revista de História da Arte, FCSH-UNL. 2011, nº1, série W: 152–173 (http://revistadehistoriadaarte.wordpress. com/). [2] M. J. Melo, A. Claro, Accounts for Chemical Research. 2010, 43, 857–866. [3] M. Leona, Proceedings of the National Academy of Sciences. 2009, 106, 14757–14762. [4] F. Pozzi, J. R. Lombardi, S. Bruni, M. Leona, Analytical Chemistry. 2012, 84, 3751–3757.

93 Book of Abstracts OP19

Characterization and Identification of Asphalts in Works of Art by SERS complemented by GC-MS, FTIR and XRF

María L. Roldan,1* Silvia A. Centeno,1 Adriana Rizzo1

1 Department of Scientific Research, The Metropolitan Museum of Art, New York, USA, +1 212 396 5509, [email protected]

Asphalts were used since antiquity for various purposes but they attained use as a pigment in the sixteenth and seventeenth centuries, and by the eighteenth century they were widely used in oil painting, ground in turpentine, particularly for glazing, shading and specifically for flesh shadows. [1,2] Asphalts were particularly appreciated because of their warm, transparent brown color that can not be achieved by using any other natural or synthetic pigment. The asphalt originated in the Dead Sea was specially valued for its great purity and the region is thought to have been the main source of the pigment between the sixteenth and the seventeenth centuries.[3] Although asphalt pigments have several properties in common, their composition and chemical properties depend on the source and on the means used for processing the natural products. Due to their complex nature asphalts are also among the most difficult pigments to firmly identify in works of art. Asphalts are mixtures of hydrocarbons with other compounds containing nitrogen, oxygen and sulphur, and may originate in sediments and rocks, a form referred to as ‘real asphalt’, or they can be artificial, i.e. derived from petroleum, coal tar, water-gas tarn, and their pitches. Asphalts have been reported to be prone to decomposition when exposed to sunlight and to have a tendency to bleed into other colors,[1] these problems may be aggravated by unsuitable conservation treatments. Therefore, knowledge of the composition of these pigments is essential to understand their interaction with the binding media and to evaluate possible conservation approaches. In this work, SERS complemented by FTIR, XRF, and GC-MS were Figure 1. SERS spectra of employed to characterize asphalt commercial samples of geological origin, different asphalt pigment including one from the Dead Sea region, and of bitumen. The SERS spectra samples: a) bitumen, b) asphalt of the asphalt samples studied here are shown in Figure 1. The optimized Zecchi, c) asphalt Rublev, d) methodology was successfully applied to firmly identify these pigments in asphalt Kremer and e) asphalt microsamples from paintings and other objects in the collection of The from the Dead Sea. λo= 514nm. Metropolitan Museum of Art.

Acknowledgements The authors thank the Andrew W. Mellon Foundation for funding.

References [1] N. Eastaugh, V. Walsh, T. Chaplin and R. Siddall, The Pigment Compendium: a Dictionary of Historical Pigments, Elsevier Butterworth-Heinemann: Oxford, 2004. [2] G. M. Languri, Molecular Studies of Asphalt, Mummy and Kassel Earth Pigments: their Characterization, Identification and Effect on the Drying of Traditional Oil Paint. Ph. D. Thesis, University of Amsterdam, 2004. [3] C. I. Bothe, Artists’ Pigments. A handbook of their History and Characteristics, vol. 4, Archetype Publications: London, 2007, p. 139.

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Study of Raman scattering and luminescence properties of orchil dye for its nondestructive identification on artworks

Francesca Rosi,1,2* Catia Clementi,3 Marco Paolantoni,3 Aldo Romani,2,3 Roberto Pellegrino,3 Brunetto Giovanni Brunetti,2,3 Witold Novik,4 Costanza Miliani1,2

1 CNR-ISTM Istituto di Scienze e Tecnologie Molecolari c/o Dipartimento di Chimica, Università degli Studi di Perugia, Italy 2 Centro di Eccellenza SMAArt Dipartimento di Chimica Università degli Studi di Perugia, Italy 3 Dipartimento di Chimica Università degli Studi di Perugia, Italy 4 Department of Chromatography (CNRS UMR 5648), Laboratoire de Recherche des Monuments Historiques, Champs-sur-Marne, France

Orcein is a natural dye widely used since ancient times for dyeing textiles but also for decorating miniatures and manuscripts. Known as the “poor person’s purple”, orcein was used in place of the more expensive Tyrian purple. Unlike the latter, orcein has a low lightfastness and in ancient works it is often faded. From a chemical point of view, orcein is a complex mixture of different compounds, they all share a common structure resulting from phenoxazone with a number of different substituents. In the present work, UV-vis fluorescence combined with micro-Raman spectroscopy allowed for the non- destructive identification of orcein in a fragment from the 9th century Bible de Théodulphe. Raman spectroscopy has been applied also for studying a parchment fragment sampled from a 16th century map of Auvergne. In both cases, subtracted shifted Raman spectroscopy (SSRS) has been exploited for removing the strong fluorescence background. Overall results have been confirmed by LC/MS Q-TOF analysis. The electronic and vibrational characterization highlighted a hypsochromic shift of the emission along with the disappearance of a strong Raman band at about 1560 cm-1 with respect to a fresh orcein standard sample. Taking into account the poor lightfastness of the purple colorant, the same investigation has been carried out on artificially aged orcein, by exposure to visible light, reproducing the spectral modification observed on the ancient fragments. Furthermore, considering that also another lichen purple dye, namely litmus, shares a similar chemical composition with orcein, a vibrational investigation has been carried out also on it highlighting spectral analogies with the two investigated fragments.

95 Book of Abstracts P20

Application to historical samples of in situ, extractionless SERS for dye analysis

Ambra Idone,1,2* Maurizio Aceto,1 Eliano Diana,3 Lorenzo Appolonia,2 Monica Gulmini3

1 Università degli Studi del Piemonte Orientale “A. Avogadro”, Dipartimento di Scienze e Innovazione Tecnologica, Alessandria, Italy, [email protected] 2 Regione Autonoma Valle d’Aosta, Direzione Ricerca e Progetti Cofinanziati, Laboratorio Analisi Scientifiche, Villair di Quart (AO), [email protected] 3 Università degli Studi di Torino, Dipartimento di Chimica, Torino, Italy, [email protected]

Silver colloidal pastes, obtained by concentrating through centrifugation chemically reduced silver colloids, have been proposed by Brosseau[1] as suitable substrates for in situ extractionless Surface Enhanced Raman Scattering (SERS) of art samples such as pigment grains and dyed fibers. The extractionless approach lowers to few nanograms the amount of sample required for the analysis and thus it is very suitable for investigating historical artworks. As far as sample preparation is concerned, the main issue consists in achieving a suitable silver coating of the complex surfaces under investigation. The morphology of the coating in fact plays the major role in promoting signal enhancement. Moreover, the interpretation of SERS spectra may be difficult due to the possible presence of degradation products, dust and restoration materials that can contribute to the overall SERS spectrum.[2] In this work, the potentiality of the application of silver colloidal pastes for the identification of natural dyes has been explored on various samples obtained from historical textiles and on cross sections obtained from painted art objects. Cross sections are usually prepared to investigate multilayered pictorial films, as they may provide large information with very small sampling. The investigation of such sections is generally carried out through optical microscopy with visible and UV light, microchemical tests and micro-Raman spectroscopy.[3] The latter technique generally provides a detailed molecular characterization of inorganic pigments, but generally fails in the identification of painting lakes,[4] which owe their color to the presence of organic dyes in small amounts. SERS represents therefore a promising tool overcoming the lack of information about the dyes used in polychromies.[5] The textiles samples considered here are few wool bundles detached from the mantle of a cope (probably dating to XVIth century) conserved in Museo del Tesoro of Aosta’s cathedral (Italy) and a very small red silk fragment of a unique tapestry dating from the end of XVth century, representing the Deposition from the Cross and conserved in Milano’s cathedral (Italy). The latter sample was already detached from the artwork and was recovered during the handling for the ongoing conservation intervention. In addition, several cross sections obtained by mounting in epoxy resin the polychrome finishing of wooden statues from Aosta Valley were considered. The corresponding painted areas, analyzed with in situ X-ray fluorescence spectroscopy, did not evidenced key-elements that might suggest the presence of a specific pigment, thus indicating that the color was obtained by organic dyes, possibly employed as lakes. Historical fibers were mildly pre-treated with water and methanol, in order to reduce the interference of contaminants on SERS spectra; fibers were then treated with the silver colloidal paste for SERS investigation. On the other hand, the coating with silver nanoparticles of the polished cross sections was obtained by employing less concentrated colloids, that allowed to record SERS spectra from the painting lakes.

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This work demonstrated that silver colloidal pastes are suitable for investigating dyes in different historical art samples. The concentration of the pastes can be modified according to the specific sample, in order to achieve the optimal coating for SERS analysis. Surface Enhanced Raman Scattering permits to deepen the knowledge of the colouring matters used in works of art as it can be applied with an extractionless approach to very small samples or to cross sections prepared for morphological and compositional analysis of painted layers.

Acknowledgements This work was carried out with the contribution of European Union, of the Regione Autonoma Valle d’Aosta and of the Italian Ministry of Labour and Social Policy.

References [1] C. L. Brosseau, A. Gambardella, F. Casadio, C. M. Grzywacz, J. Wouters, R. P. Van Duyne, Anal. Chem. 2009, 81, 3056. [2] C. L. Brosseau, K. S. Rayner, F. Casadio, C. M. Grzywacz, R. P. Van Duyne, Anal. Chem. 2009, 81, 7443. [3] L. Appolonia, D. Vaudan, V. Chatel, M. Aceto, P. Mirti, Anal. Bioanal. Chem. 2009, 395, 2005. [4] L. Bellot-Gurlet, S. Pagès-Camagna, C. Coupry, J. Raman Spectrosc. 2006, 37, 962. [5] F. Casadio, M. Leona, J. R. Lombardi, R. Van Duyne, Accounts Chem. Res. 2010, 43, 782.

97 Book of Abstracts P21

Application of surface-enhanced Raman spectroscopy (SERS) to the analysis of red lakes in French Impressionist and Post-Impressionist paintings

Federica Pozzi,1* Francesca Casadio1

1 Department of Conservation Science, Art Institute of Chicago, Chicago, USA, +1(312)443-7209, [email protected]

The Art Institute of Chicago’s collection of Impressionist and Post-Impressionist paintings is the largest and among the very finest outside of France. The museum’s holdings embrace several invaluable works of art, including masterpieces by Manet, Monet, Renoir and the influential Post-Impressionist canvases of Gauguin and Van Gogh.[1] An extensive and systematic technical study of the entire collection of French 19th century paintings is currently being undertaken, to be published in a comprehensive online scholarly catalogue.

Scientific analysis is essential to address conservation treatments and help scholars develop a wider knowledge of the artists’ resources, techniques and original intentions. For Impressionism a strong, direct relationship can be established between the materials chosen, including ground and paint colours, and the type of light and tonal effects to be represented. Their practice was also heavily influenced by the availability of new painting materials originating from the Industrial and Scientific Revolutions, which led to a significant expansion of the artists’ palette, starting in the 1870s.

The identification of red organic lakes, used by the Impressionists for their brilliant color, is significantly more challenging than the analysis of most inorganic pigments. Many techniques have been tested over the decades for this purpose, including UV-visible absorbance [2] and reflectance [3] spectroscopy, thin layer chromatography (TLC) [4] and high-performance liquid chromatography (HPLC).[5] In most cases, though, electronic methods are strongly affected by matrix interference and show poor specificity. On the other hand, chromatographic techniques require relatively large samples, which often cannot be removed from priceless artifacts. Raman spectroscopy has also been employed to examine both natural and synthetic pigments.[6,7] However, this technique has its own limitations, first of which is the inherent weakness of the Raman signals that can be obscured by the molecular fluorescence typical of some organic materials such as dyestuffs.

Since its discovery in 1974, surface-enhanced Raman spectroscopy (SERS) has been exploited as a powerful tool for the sensitive and selective detection of organic molecules adsorbed on noble metal nanostructures.[8] The applications of SERS in the field of cultural heritage materials, and particularly for the identification of organic colorants, has been widely demonstrated,[9] and latest improvements have made measurements possible on a single pigment grain or a few-microns length of fiber.[10]

In this work, we will present examples of application of the SERS technique to the detection and identification of red lakes from masterpieces belonging to the French Impressionist and Post- Impressionist collection of paintings of the Art Institute of Chicago. Extensive usage of sometimes more than one type of red lakes in a single painting will be discussed, as well as the issue of fading. Comparison of different methodologies to deliver the plasmonic probe to the organic moieties will be presented. This study enhances the knowledge base of the red lake pigments used by Impressionist

RAA 2013 98 P21 artists, materials that have so far mostly eluded other comprehensive studies of the Impressionist palette because of the analytical limitations described above.

Figure 1. On the left, Renoir’s Near the lake, 1879/80; Art Institute of Chicago, oil on canvas, 18 x 22 inches (47.5 x 56.3 cm); Potter Palmer Collection, accession number 1922.439. On the right, the SERS spectrum obtained for a red lake sample taken from the proper left edge of the painting (top) is compared with a reference spectrum of a commercial madder lake (bottom).

Acknowledgements This work has been financially supported by the A. W. Mellon Foundation.

References [1] G. Groom, D. Druick, The age of French Impressionism. Masterpieces from the Art Institute of Chicago. Yale University Press: New Haven, London, 2010. [2] G.W. Taylor, Studies in Conservation. 1983, 28, 153. [3] M. Leona, J. Winter. Studies in Conservation. 2001, 46, 153. [4] H. Schweppe, Handbuch der naturfarbstoffe. Landsberg/Lech, Germany, 1993. [5] M. R. Van Bommel, I. Vanden Berghe, A. M. Wallert, R. Boitelle, J. Wouters, J. of Chromatography A. 2007, 1157, 260. [6] G. Smith, J. H. Clark, Reviews in Conservation. 2001, 2, 92. [7] F. Schulte, K. W. Brzezinka, K. Lutzenberger, H. Stege, U. Panne, J. of Raman Spectrosc. 2008, 39, 1455. [8] P. L. Stiles, J. A. Dieringer, N. C. Shah, R. P. Van Duyne, Annual Review of Analytical Chemistry. 2008, 1, 601. [9] F. Casadio, M. Leona, J. R. Lombardi, R. Van Duyne. Accounts of Chemical Research. 2010, 43, 782. [10] F. Pozzi, J. R. Lombardi, S. Bruni, M. Leona, Analytical Chemistry. 2012, 84, 3751.

99 Book of Abstracts P22

Surface-Enhanced Raman Spectroscopy (SERS) of historical dyes on textile fibres: evaluation of an extractionless treatment of samples

Chiara Zaffino,1* Silvia Bruni,1 Vittoria Guglielmi1

1 Dipartimento di Chimica, Università degli Studi di Milano, Italy, [email protected]

Most natural organic dyes are fixed on textiles by mordanting, i.e. by treating the fiber with metal salts (e.g. aluminium salts) so that the metal ion mediates the interaction between the dye molecule and the fiber itself. As a result, for SERS analysis of historical textiles it is usually necessary to extract the dye itself from the ancient artefact by more or less aggressive hydrolysis methods. Of course, the extraction procedure is time-consuming and leads to the destruction of the sample. For this reason, in recent times many researchers began to propose various extractionless procedures, to be applied directly on mordanted textile fibers.[1–-3] Indeed, some of these methods require silver colloids obtained

by unconventional synthesis, such as microwave reduction of Ag2SO4 or in situ photo-reduction of Ag nanoparticles. On the other hand, Brosseau and co-workers [3] managed to obtain reliable extractionless non-hydrolysis SERS spectra with citrate-reduced Ag colloids. Similarly to this latest publication, the present work studies the applicability of a procedure, based on the use of an Ag Lee-Meisel colloid [4] to obtain SERS spectra directly from fibers. The advantage of using this sol synthesis is its easiness, since it doesn't require any specific instrumentation. The analyzed fibers are both wool threads dyed in our laboratory according to historical recipes and ancient textile samples. Reference wool threads had been [5] washed, treated with alum, KAl(SO4)2 and with acid potassium tartrate and finally dyed, while the ancient samples analyzed come from textile manufacts belonging to the gallery Moshe Tabibnia, Milan.

Special attention was paid to the possibility to obtain a reliable SERS spectrum from amounts of sample as small as possible, so that the method can be considered, if not entirely non destructive, at least micro-destructive and to the possibility to use different excitation wavelengths besides the green one frequently employed, for example a near infrared radiation as in the FT-Raman technique. As regards the use of this excitation source, it is well known that different excitation wavelengths can enhance different vibrational modes in the resulting SERS spectrum: indeed, there are significant differences between the SERS spectra of our previous database,[6] recorded at 532 nm and the FT-SERS spectra collected with excitation at 1064 nm. Thus FT-SERS spectra of reference dyes in solution were collected in order to obtain more suitable references in the near-infrared (NIR) region. The aim to reduce, as much as possible, the size of the thread used for the analysis has been achieved: starting from 5 mm of thread initially subjected to analysis, we decreased the sample dimensions, in most cases, to a single fiber of wool, thus making the technique nearly non-destructive. As regards the second point, FT-SERS spectra on dyed wool were recorded on a wide range of colorants, leading to the construction of a new database. It collects spectra of some chromophores and of many natural organic dyes which belong to several molecular classes, namely anthraquinones, flavonoids, neoflavonoids, biflavonoids, carotenoids, curcuminoids, naphthoquinones, and gallotannins. Good results were also achieved on ancient textile samples with the use of an excitation wavelength of 532 nm, while studies about the development of a FT-SERS procedure for the identification of dyes in ancient samples are still in progress.

References [1] M. Leona, J. Stenger, E. Ferloni, J. of Raman Spectrosc. 2006, 37, 981–992. [2] Z. Jurasekova, C. Domingo, J. V. Garcia-Ramos, S. Sanchez-Cortes, J. of Raman Spectrosc. 2008, 39, 1309–1312.

RAA 2013 100 P22

[3] C. L. Brosseau, A. Gambardella, F. Casadio, C. M. Grzywacz, J. Wouters, R. P. Van Duyne, Analytical Chemistry. 2009, 81, 3056–3062. [4] P. C. Lee, D. Meisel, J. of Physical Chemistry. 1982, 86, 3391–3395. [5] S. Bruni, E. De Luca, V. Gugliemi, F. Pozzi, Applied Spectroscopy. 2011, 65, 1017–1023. [6] S. Bruni, V. Guglielmi, F. Pozzi, J. of Raman Spectrosc. 2011, 42, 1267–1281.

101 Book of Abstracts P23

Suitability of Ag-agar gel for the micro-extraction of organic dyes on different substrates: the case study of wool, silk, printed cotton and panel painting mock-ups

Elena Platania,1,2,3* Marco Leona,2 John R. Lombardi,3 Cristiana Lofrumento,1 Marilena Ricci,1 Maurizio Becucci,1,4 Emilio Castellucci1,4

1 University of Florence, Chemistry Department “U.Schiff”, Italy, +39 055 4573066, [email protected]. 2 Department of Scientific Research, The Metropolitan Museum of Art, New York, USA, +1 (212)3965476, [email protected]. 3 Department of Chemistry and Center for Analysis of Structures and Interfaces (CASI), The City College of New York, USA, +1 (212) 650-6032, [email protected]. 4 University of Florence, European Laboratory for Non-linear Spectroscopy (LENS), Italy, +39 055 4572491, [email protected].

Micro-Raman spectroscopy has been a very reliable technique for the characterization of artists’ pigments and pictorial materials. However, the analysis of organic dyes by means of conventional dispersive Raman spectroscopy is a very challenging problem. The difficulties encountered in the characterization of this class of materials stem mainly from their high fluorescence emission upon laser excitation, which covers the weak Raman signal. Moreover, due to their high tinting power, these compounds are present at very low concentrations in artifacts. Among the most commonly used techniques for the identification of dyes, high performance liquid chromatography (HPLC) has been widely employed for the study of this class of materials in archaeological artworks and historical textiles, due to its ability to resolve complex mixtures of compounds.[1,2] Despite its high sensitivity, HPLC requires large samples (1 or 2 mm of a fabric thread) for analysis, raising concerns about the preservation of the physical integrity of the art object. Although currently available non-invasive methods, such as UV–visible absorption or fluorescence spectroscopy, help allay concerns about maintaining the integrity of the artifact, unfortunately, they are of limited use due to their poor specificity. In the last few years, surface enhanced Raman spectroscopy (SERS) has become a powerful analytical technique for the study of fluorescent organic materials of artistic interest. Recently, interesting methods, adopting polymers and sol-gel matrices, have been developed for the identification of molecules at extremely low concentrations.[3] This aspect has attracted the field of dye analysis in artworks, providing cutting-edge methodologies for the study of this class of materials, such as polymeric beads of methacrylate [4] for a non-destructive extraction of dyes from ancient textiles and drawings; organic modified silicate matrices, combined with zirconium, tailored for a selective identification of alizarin;[5] methylcellulose active films for the detection of painting lakes[6]. In particular agar-agar, successfully applied in the field of stone works,[7] paintings[8] and paper cleaning,[9] and combined with silver nanoparticles for the production of antibacterial organic-inorganic systems, [10] has been selected as an ideal gelling material for our research. As introduced in a previous work [11], a nanocomposite Ag-agar hydrogel has been developed for non-destructive extraction of dyes from artworks. The nanocomposite gel has enabled the accomplishment of two important goals. In fact, it acts not only as an absorbent probe for the micro-extraction of dye molecules from textiles, but also as efficient enhancer of Raman scattering, due to the silver nanoparticles trapped in its structure. The system has been found to be extremely stable, easy to use and to produce, minimally invasive, easy to store and

RAA 2013 102 P23 able to be analyzed even after long time intervals, maintaining unaltered its enhancement properties without detriment of the extracted compound. Moreover, the shrinkage of the gel upon drying makes it an excellent mechanical molecular trap for the silver nanoparticles, which approach each other as the network volume decreases. This process generates high plasmonic electromagnetic fields that engender the Raman signal amplification.[12] In this work, Ag-agar gel, successfully applied for the micro-extraction of anthraquinone dyes on cotton, have been tested on new different substrates, such as wool, silk, printed cotton and panel painting mock-ups, for the detection of alizarin, purpurin, carminic acid and laccaic acid. Micro- extractions have been performed also on pieces of printed cotton dyed with unknown dyes. SERS measurements, of the nanocomposite matrix, have revealed the presence of alizarin. Cross reference HPLC analyses, performed on the same pieces of textile, have confirmed the SERS results, showing the suitability of the technique. Ag-agar gel has been synthesized adding new chemicals within its structure, such as chelating agents (EDTA) and aggregating salts (KNO3) in order to improve both the dye micro-extraction and the enhancement of the Raman scattering.

Acknowledgements This work was supported primarily by the Department of Justice Office of Justice Programs, National Institute of Justice Cooperative Figure 1. SERS spectrum of alizarin collected after micro- Agreement 2009-DN-BX-K185. and partially by extraction by Ag-agar gel/EDTA on a piece of silk dyed with madder the Center for Exploitation of Nanostructures in and mordented with alum. Senor and Energy Systems (CENSES) under NSF Cooperative Agreement Award Number 0833180.

References [1] Z. C. Koren, J. Soc. Dyers Colour. 1994, 110, 273. [2] I. Degano, E. Ribechini, F. Modugno, M. P. Colombini, Appl. Spectrosc. Review. 2009, 44, 363. [3] S. E. J. Bell, S. J. Spence, Analyst. 2001, 126, 1. [4] M. Leona, P. Decuzzi, T. A. Kubic, G. Gates, J. R. Lombardi, Anal. Chem. 2011, 83, 3990. [5] S. Murcia-Mascarós, C. Domingo, S. Sanchez-Cortes, M. V. Cañamares, J. V. Garcia-Ramos, J. Raman Spectrosc. 2005, 36, 420. [6] B. Doherty, B. G. Brunetti, A. Sgamellotti, C. Miliani, J. Raman Spectrosc. 2011, 42, 1932. [7] E. Campani, A. Casoli, P. Cremonesi, I. Saccani, E. Signorini, Quaderno n.4/CESMAR7, Il Prato, Padova, 2007. [8] E. Carretti, M. Bonini, L. Dei, B. H. Berrie, L. V. Angelova, P. Baglioni, R. G. Weiss, Acc. Chem. Res. 2010, 43, 751. [9] S. Iannuccelli, S. Sotgiu, Quaderni, Gangemi: Roma, 2010. [10] S. Ghosh, R. Kaushik, K. Nagalakshmi, S. L. Hoti, G. A. Menezes, B. N. Harish, H. N. Vasan, Carbohydr. Res. 2010, 345, 2220. [11] Lofrumento C., Ricci M., Platania E., Becucci M., Castellucci E., J. Raman Spectrosc. 2012, 44, 47. [12] P. Aldeanueva-Potel, E. Faoucher, R. A. Alvarez-Puebla, L. M. Liz-Marzàn, M. Brust, Anal. Chem. 2009, 81, 9233.

103 Book of Abstracts P24

PB15 polymorphic distinction in paint samples by combining micro- Raman spectroscopy and chemometrical analysis

Jolien Van Pevenage,1* Cathérine Defeyt,2 Luc Moens,1 David Strivay, 2 Peter Vandenabeele3

1 Ghent University, Department of Analytical Chemistry, Raman Spectroscopy Research Group, Ghent, Belgium, +32 9 2644719, [email protected] 2 Centre Européen d’Archéometrie and Institut de Physique Nucléaire, Atomique et de Spectroscopie, Universié de Liège, Belgium, [email protected] 3 Ghent University, Department of Archaeology, Archaeometry Research Group, Ghent, Belgium, Peter [email protected]

In art analysis of 20th centur y artworks, copper phthalocyanine (CuPc) is often identified as an important pigment (PB15). It is used in different polymorphic forms and identification of the polymorph could retrieve information on the production process of the pigment, at the time.

This pigment can be detected by Raman spectroscopy, which is a molecular spectroscopic technique. Moreover, Raman spectroscopic analysis makes it possible to discriminate between polymorphs of crystals. However, in the case of PB15, spectral interpretation is not straightforward. In order to discriminate the polymorphs of PB15 in paints, Raman data treatment requires some improvements. Here, Raman spectroscopy is combined with chemometrical analysis in order to develop a procedure allowing us to identify the PB15 crystalline structure in painted layers and in artworks. To be able to discriminate between different CuPc polymorphs, different chemometrical approaches were first tested on pigment samples. And in a second stage, the selected procedure was extended towards paint samples.

In the developed procedure, after manual baseline correction of the spectra, 12 intensity ratios of certain band positions were selected to be used as input to linear discriminant analysis (LDA).[1] 10 of these band ratios had been proposed in a recent study [2] as polymorphic markers. From our observations,

two supplementary intensity ratios (I1141 / I1105 and I775 / I715) could also contribute to our aim. Further, the band ratios were vector-normalised for all the spectra in the dataset. As linear discriminant analysis is a supervised classification method, the dataset has to be split in a training set – used to develop the classification model – and a validation set, to evaluate the outcome from the analysis. The best results were obtained using leave-one-out classification. In this classification method, each case (or spectrum) included in the analysis is classified by the functions derived from all cases other than that case.

Applying the developed procedure to a dataset, that includes Raman spectra of pigments and paint samples on the one hand, and only paint samples on the other hand, it turns out that in general, it is possible to discriminate between different CuPc polymorphs. In the first case, we observe that 92% of the paint samples are correctly classified. In the latter case, the results are even better, and a correct classification of 96% is observed.

So in the end there can be concluded that the combination of Raman spectroscopy and LDA (using intensity ratios and evaluated by the leave-one-out algorithm) is a very valuable non-destructive

RAA 2013 104 P24 method to identify the crystalline structure of a PB15 pigment in painted layers.

Acknowledgements The authors wish to acknowledge the MEMORI project for its financial support. The MEMORI project, ‘Measurement, Effect Assessment and Mitigation of Pollutant Impact on Movable Cultural Assets. Innovative Research for Market Transfer‘ is supported through the 7th Framework Programme of the European Commission (http://www.memori-project.eu/memori.html).

References [1] G. Darren, P. Mallery. SPSS For Windows. Needham Heights, Massachusetts: Allyn & Bacon, 2001. [2] C. Defeyt, P. Vandenabeele, B. Gilbert, J. Van Pevenage, R. Cloots, D. Strivay, J. of Raman Spectrosc. 2012, 43(11), 1772–1780.

105 Book of Abstracts P25

First identification of the painting technique in 18th Century Transylvanian oil paintings using micro-Raman and SERS

Oana-Mara Gui,1,2 Simona Cînta-Pînzaru3*

1 Technical University Cluj-Napoca, Faculty of Materials’ Science and Engineering, Cluj-Napoca, Romania, [email protected] 2 University of Art and Design Cluj-Napoca, Cluj-Napoca, Romania 3 Babes-Bolyai University, Biomedical Physics, Theoretic and Molecular Spectroscopy Dept., Cluj Napoca, Romania, [email protected]

The investigation of cultural heritage objects has become increasingly centered in the past decade on the characterisation of the materials and the painting techniques.[1] as a means of better understanding historic context, conservation state and of projecting future restoration work. In such context, Raman spectroscopy proves to be a versatile tool in what it can offer insight into the nature of both organic and inorganic materials, without damaging the sample and often enabling in-situ characterisation of the artwork.[2]

Here we report the first identification of the painting technique of two th18 century portraits of the Transylvanian noble family Banffy using SERS. Although recent investigations into clerical Romanian art shed light on the preferred painting technique of the local craftsmen (mostly, egg-based tempera [3]) no information was available on the art comissioned by noblemen. In order to better understand such cultural heritage items, micro-samples were removed from both the paint layers and the canvas supports of the paintings and were subjected to analysis with little or no preparation.

Aiming to reduce the amount of pictorial material sampled, micro-Raman and SERS measurements were carried out directly on paint micro-samples and linen threads and allowed simultaneous identification of both organic and inorganic painting components, including the canvas support. Micro- Raman was also performed on paint cross-sections, in order to better localize painting material into the different layers.

Investigations revealed a western European painting technique which made use of a lipid binder and two differently colored preparation layers. Raman investigations showed that artists used both common pigments for the Transylvanian region such as lamp black (having characteristic Raman peaks at 1330 and 1590 cm-1) as well as the uncommon or even expensive pigments such as massicot (showing characteristic peaks at 135 (s), 267 (m) and 362 (w) cm-1) and vermillion (252 (s) and 342 (m) cm1 [Clark et al, 1997]), which was surprisingly found in the preparation layers. SERS analyses of the canvas support suggested that a high lignin containing fiber was used, as aromatic ring deformations [5] were observed together with a huge band at 238 cm-1 which is due to the chemisorption of lignin on Ag nanoparticles. Moreover, due to the fluorescence quenching effect of the SERS substrate, bands of the cellulose could also be observed even when using a 785 nm wavelength excitation laser: the δ(CCC) -1 -1 ring deformation at 466 cm , the ρ(CH2) broad band at ~960 cm or the ν(COC) glycoside doublet at 1100 cm-1.[6]

To the best of our knowledge this is the first attempt to characterize Transylvanian oil paintings dating before the 1800s.

RAA 2013 106 P25

Acknowledgements This work has been financially supported by the QDOC project, contract no. POSDRU/107/1.5/S/78534. The authors would like to thank the Cluj-Napoca Art Museum for providing samples and photographs of the oil paintings.

References [1] C. Ricci, I. Borgia, B. G. Brunetti, C. Miliani, A. Sgamellotti, C. Seccaroni, P. Passalacqua, J. Raman Spectrosc. 2004, 35, 616–621. [2] P. Vandenabeele, M. C. Christensen, L. Moens, J. Raman Spectrosc. 2008, 39, 1030–1034. [3] M. Guttmann, Journal of Cultural Heritage. 2012, http://dx.doi.org/10.1016/j.culher.2012.10.009. U. P. Agarwal, R.S. Reiner, J. of Raman Spectrosc. 2009, 40, 1527–1534. [4] H. G. M. Edwards, N. F. Nikhassan, D. W. Farwell, P. Garside, P. Wyeth, J. of Raman Spectrosc. 2006, 37, 1193–1200.

107 Book of Abstracts P26

Organic materials in oil paintings and canvas revealed by SERS

Oana-Mara Gui,1,2 Simona Cînta-Pînzaru3*

1 Technical University Cluj-Napoca, Faculty of Materials’ Science and Engineering, Cluj-Napoca, Romania, [email protected] 2 University of Art and Design Cluj-Napoca, Cluj-Napoca, Romania 3 Babes-Bolyai University, Biomedical Physics, Theoretics and Molecular Spectroscopy Dept, Cluj-Napoca, Romania, [email protected]

The characterisation of organic materials used in oil paintings is a great challenge for any Raman technique. We summarize here our recent results in the topic, using surface enhanced Raman scattering (SERS) to analyse new and artificially aged organic materials. This current work on organic painting materials presents an innovative approach to artwork and especially plant fibre analysis based on the use of different SERS-active colloidal nanoparticles. The investigated materials included new and artificially aged oil painting replicas, as well as samples form cultural heritage canvases of Romanian and Italian origin, dating from 1700 to 1900. Materials were chosen to cover different variations of the same technique (oil painting) as well as different stages of ageing. All samples were subjected to analysis without any prior preparation.

The most interesting results were obtained for the canvas supports, where lignin bands were enhanced after direct immersion in Ag colloidal solutions and specific Raman bands corresponding to aromatic ring could be observed between 300 and 1600 cm-1 (Figure 1 A) [1] Because of the huge fluorescence signal of the fibers to any laser lines from visible to NIR, we employed surface enhanced Raman scattering to exprore the possibility to detect trace amounts of species that are not available in normal Raman measurements.

Taking into account that lignin counts for less than 4% in the pure linen fibre, this is not detectable in a normal Raman experiment of linen.

For SERS analysis, the chemisorption of lignin is proven by the huge band at 238 cm-1 which appeared in all canvas samples. As compared to FT-Raman analyses carried on the same samples, SERS proved to be advantageous because it allowed for a very fast detection of lignin (total analysis time was under 30 seconds) while providing a less fluorescent spectrum. The FT-Raman spectrum acquired on the same sample prior to SERS and consisting of 1000 acquisitions shows a weaker and more fluorescent signal (Figure 1 B). Although SERS does not enhance cellulose signals, the background quenching effect of SERS enabled the observation of bands specific for the polysaccharide such as the glycosidic doublet around 1100 cm-1 [2].

Another significant advantage of SERS is the possibility to evidence traces of protein species in the

RAA 2013 108 P26 samples. A complex band at 1650 cm-1 could be detected on linen fibres from the 1835 painting, thus hinting towards a contribution from the amide I band characteristic for proteins. For protein samples (animal glue), Ag nanoparticles allowed the detection of the amide I band at 1658 cm-1 together with the amide V band at 730 cm -1 (not shown here). No SERS effect was observed when employing the Ag NPs on lipid binders. This allows for a fast discrimination between protein-based and lipid-based materials within complex samples, and has application in paint cross-section analyses by SERS [3].

The study enabled the selection of the best colloidal nanoparticles for SERS enhancement of bands characteristic for plant-based fibres and other organic materials employed in canvas painting. By making use of low laser power and low integration times while also providing reproducible results, this SERS approach to investigating binding media and canvas supports has great potential for either in situ applications or cross-section analysis of heritage samples.

Acknowledgements This work has been financially supported by the QDOC project, contract no. POSDRU/107/1.5/S/78534. The authors are grateful to the Cluj-Napoca Museum of Art for providing samples from Romanian cultural heritage paintings and to restorer Belinda Giambra and Soprintendenza dei BB.CC.AA. Caltanissetta for samples from the Italian painting.

References [1] M. O. Gui, A. Falamas, L. Barbu-Tudoran, M. Aluas, B. Giambra, S. Cinta Pinzaru., J. of Raman Spectrosc. 2013, 44, 277–282. [2] P. Adapa, C. Karunakaran, L. Tabil, G. Schoenau, Agricultural Engineering International: CIGR Journal. Manuscript 1081. 2009, XI. [3] L. H. Oakley, S. A. Dinehart, S. A. Svoboda, K. L. Wustholz, Analytical Chemistry. 2011, 83, 3986–3989.

109 Book of Abstracts P27

Characterization of SOPs in acrylic and alkyd paints by means of µ-Raman spectroscopy

Marta Anghelone,1,2* Dubravka Jembrih-Simbürger,1 Manfred Schreiner1,2

1 Institute of Science and Technology in Art, Academy of Fine Arts, Vienna, Austria, +43 1 58816 8662, [email protected], D. [email protected], [email protected] 2 Institute of Chemical Technologies and Analytics, Analytical Chemistry Division, Vienna University of Technology, Vienna, Austria

Synthetic modern materials are nowadays used in all fields of contemporary art and their study is getting of primary importance, particularly to understand how they interact with each other and how they behave with time, aming to establish appropriate preservation and conservation strategies. Therefore, a systematic investigation of synthetic organic pigments (SOPs), above all phthalocyanines, and modern binding media, such as acryl and alkyd, have been carried out. Since Raman spectroscopy proved to be a particularly appropriate tool to be employed for this purpose, [1] the method was included in the study.

Figure 1. Raman spectra obtained with an excitation wavelength of 532 nm for phthalocyanine blue pigment (PB15:3), acrylic binding medium (Plextol) and for a mixture of both, PB15:3 + Plextol.

The aim of this work is to evaluate the influence of different excitation wavelengths and of the presence of binding media on the characterization of SOPs by means of µ-Raman spectroscopy [2]. Thus, Synthetic Organic Pigments representative for different chemical classes [3] were collected from various manufacturers and used for preparing mock-ups. Therefore the pigment powders were mixed with binders (Plextol: n-butylacryl/ methylmethacrylate) and alkyd resin (Lukas medium 4) of known chemical composition and cast on glass slides. The thickness of the paints was 150 µm (wet). The homogeneity, thickness and aspect of the paint layers was studied and documented by optical microscopy on cross-sections. For the preparation of mock-ups no additives were employed, in order to obtain a simple two component (pigment-binder) system. Finally, pure pigment powders, pure binding

RAA 2013 110 P27 media and mock-up samples were analysed performing µ-Raman spectroscopy. Three excitation wavelengths (532, 632.8 and 785 nm) were employed in order to observe and to compare the effects caused by the presence of binding media, trying to avoid fluorescence. In particular the attention was focused on phthalocyanine blue and green pigments,[4] on the identification and classification of their polymorphs,[5] and on the interaction with the binding media. The results show that pure pigments and pure binding media can be easily identified in a range between 200 and 1800 cm-1, especially using 532 nm and 632.8 nm lasers for the excitation. In the case of mock-up samples, µ-Raman measurements allowed to identify the pigments despite the presence of the binding medium. By extending the range of acquisition to 3500 cm-1, it was possible to detect the binder itself (Figure 1). An excitation wavelength of 532 nm was found to be particularly suitable, while adopting a 632.8 nm laser, fluorescence effect was present. Nevertheless an identification of the components (pigments and binders) could be achieved.

References [1] C. Scherrer, S. Zumbuehl, F. Delavy, A. Fritsch, R. Kuehnen, Spectrochimica Acta Part A, 2009, 73, 505. [2] K. Trentelman, C. Havlik, M. Picollo (Editor), The Sixth Infrared and Raman Users Group Conference (IRUG6), Il Prato, Italy, 2004, p. 94. [3] S. Q. Lomax, T. Learner, J. of the American Institute for Conservation, 2006, 45(2), 107. [4] D. R. Tackley, G. Dent, W.E. Smith, Physical Chemistry Chemical Physics, 2001, 3, 1419. [5] M. A. Shaibat, L. B. Casabianca, D. Y. Siberio-Pèrez, A. J. Matzger, Y. Ishii, Journal of Physical Chemistry B. 2010, 114(13), 4400.

111 Book of Abstracts P28

Synthetic Polymers and Cultural Heritage. An Analytical Approach by Raman Spectroscopy

Margarita San Andrés,1* Valentín G. Baonza,2 Oscar R. Montoro,2 Adrián Bouzas,2 Ruth Chércoles,1 Mercedes Taravillo,2 José Manuel de la Roja1

1 Universidad Complutense, Facultad de Bellas Artes, Dpto. de Pintura-Restauración, Madrid, Spain, +34 91 394 36 40, [email protected] 2 MALTA-Consolider Team & QUIMAPRES Team, Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Spain, +34 91 394 42 62, [email protected]

Since the middle of last century, the use of synthetic polymers has widely spread in the field of heritage. These new materials have been used by modern and contemporary artists, so they are an important part of the collections of Museums, for example, MNCARS (Madrid), Tate Gallery (London) and MOMA (New York). On the other hand, they are commonly used in preventive conservation tasks, such as: packaging, exhibition, handling and storage. In these cases, these materials are used for supports, protectors and/or thermal and electrical insulators. Synthetic polymers are also part of materials applied in restoration of artworks, for example, as coatings, adhesives, fixatives, varnishes and consolidants. However, existing synthetic polymers and related materials are rarely developed to be specifically used in the field of heritage. Furthermore, the information provided by the manufacturer is quite limited and sometimes inaccurate. For these reasons, it is necessary to achieve the data about its composition and long-term behavior, considering that both issues are in fact closely related. In order to perform such investigation it must be recognized that commercial products are often complex materials, since, apart from the polymeric matrix, many other components may be present. The most common added components are plasticizers, lubricants, pigments, extenders, fillers, colorants, antioxidants, and/or UV absorbents, among others. Some components, like plasticizers and lubricants, are added for easy processing, while others, like pigments and antioxidants, help to improve the properties and features of the final product. In any case, regardless the function of the additives, they must be identified and their stability must be also known, especially if they are part of artworks or will be in contact with them. There are several analytical techniques which are suited for identifying polymeric materials.[1] The most common are: chromatographic (GC-MS and Py-GC-MS), thermal analysis (DSC and TGA) and vibrational spectroscopic techniques. With respect to the latter, Fourier transform infrared (FTIR) is very useful and has been used in analytical characterization of polymers relevant in conservation and restoration.[2] It is also useful for assessing the behavior of polymeric materials with aging, although such studies usually benefit from complementary analyses with other techniques, especially chromatographic and thermal analyses.[3,4] As it is well known, Raman and FTIR spectra provide complementary information, since weak FTIR absorptions usually show strong Raman features and vice-versa. On the other hand, in the case of polymeric materials, Raman spectroscopy provides useful information about chain´s orientation, crystallinity and the evolution of these properties with the aging process. The study of all of these factors is important because they modify the physical properties of plastics and also their practical uses.[5] In order to improve the Raman spectroscopic data existing about commercial materials used in tasks of preventive conservation, here we present the analysis carried out in some selected products. The

RAA 2013 112 P28 materials analyzed include adhesives, nonwoven fabrics, supports, insulating materials and foams. Some of them are polymer blends and composite materials.

Experimental The materials analyzed in this work are: Cellaire®, Ethafoam®, Plastazote®, Lampraseal®, Marvelseal®, Tyvek® tape, BEVA® Film 371, Melinex®, Polyfelt, Lexan®, Coroplast®, Polionda® and sheet JCR. The samples were characterized by a confocal micro-Raman spectrometer (BWTEK VoyageTM BWS435-532SY) coupled to an Olympus BX51 microsco-pe. Raman spectra are taken at room temperature by using a 532.0 nm laser line at a power of 2-3 mW. The excited Raman scattering signal is collected through a 20x long working distance objective. The spot size of the incident light is about 8 μm2 on the sample. Our results cover the 100–3750 cm−1 spectral range and their spectral resolution was 3.8 cm−1.

Results The polymers identified have been polyolefins, polyesters, polyamides, polycarbonates and others. Figure 1 contains Raman spectra corresponding to a foam film, marketed as Cellaire®, and a plastic sheath, marketed as sheet JCR. Cellaire® presents characteristic bands attributed to a low-density polyethylene (2882, 2848, 2722, 1459, 1440, 1295, 1127 and 1062 cm−1) and sheet JCR shows features that suggest that is a polyethylene terephthalate (3084, 1728, 1616, 1098 and 563 cm−1). Raman spectra of the other samples investigated have allowed their analytical characterization.

Figure 1. Raman spectra for Cellaire® and sheet JCR.

Acknowledgements This work has been funded by the Spanish Ministry of Science and Innovation under Projects CTQ2010-20831, CTQ2012-38599-C02-02 and MALTA-Consolider Ingenio 2010 (CSD2007-00045). The authors are also grateful to the Science and Technology of Heritage Conservation Laboratory Network (RedLabPat), CEI, Moncloa Campus (UCM-UPM) and Comunidad de Madrid and EU though the QUIMAPRES-S2009/PPQ-1551 program.

References [1] M. J. Forrest, Analysis of Plastics. Rapra Review Reports. Expert overviews covering the science and technology of rubber and plastics, vol. 13, nº 5, Smithers Rapra Press: Shrewsbury, 2002. [2] R. Chércoles, M. San Andrés, J. M. De la Roja, M. L. Gómez, Analytical and Bioanalytical Chemistry, 2009, 395, 2082–2096. [3] M. Lazzari, A. Ledo-Suárez, T. López, D. Scalarone, M. A. López-Quintela, Analytical and Bioanalytical Chemistry, 2011, 399, 2939–2948. [4] M. San Andrés, R. Chércoles, S. Santos, J. M. de la Roja, C. Domínguez, M. L. Gómez, Science and Technology for the Conservation of Cultural Heritage, Taylor & Francis: Oxford, 2013 (in press). [5] Y. Shashoua, Conservation of plastics. Materials science, degradation and preservation, Butterworth- Heinemann: London, 2008, pp. 93–95.

113 Book of Abstracts P29

Raman monitoring of the sol-gel process on OTES/TEOS hybrid sols for the protection of historical glasses

L. de Ferri,1 A. Lorenzi,2,3 P. P. Lottici,2,4 A. Montenero2,3

1 Chemistry, Materials and Chemical Engineering Department, Politecnico di Milano, V. L., Italy, +390223994741, [email protected] 2 CIPACK Center, Parma, Italy 3 Chemistry Department, Università degli Studi di Parma Parco Area delle Scienze 17/A, Parma, Italy, +390521905444, [email protected] 4 Physics and Earth Sciences Department, Università degli Studi di Parma, Parma, Italy, +390521905238, [email protected]

In the frame of a wider research work focused on the study of Medieval Potash-Lime-Silica (PLS) glass, several hybrid sols have been studied as water repellent protective coating for historical windows. The sol gel process currently is one of the most used methods to study new chemical products for the conservation of the Cultural Heritage. For historical windows the sols should achieve the protection from the most diffused weathering agents

(SOx, NOx, CO2…) dissolved in the environmental water that acts like a trigger for the glass alteration mechanisms. Currently the protection of historical windows is achieved by the installation of protective glazing on the external surface of the windows or by the application of resins. In the first case the slabs strongly reduce the transmission of light, darkening the glasses colours and having a bad impact on the appearance of the monuments [1]. The acrylic resins have, as main drawbacks, the physical and chemical incompatibility with the inorganic substrate, the occurrence of yellowing phenomena due to [2] the photo-oxidation and the thermal instability since their Tg range between 15 and 40°C . In this work TEOS (Tetraethylorthosilicate) based sols -in isopropanol as solvent and using HCl as catalyst- have been added with several functionalized Si-alkoxides in different proportions to achieve good surface water repellency. Three compositions are particularly effective: 80%TEOS-20%OTES (Octyltriethoxysilane), 95% TEOS-5% HDTMS (Hexamethyltrimethoxysilane) and 75%TEOS- 20%OTES-5%HDTMS. The sol gel process was followed by Raman spectroscopy to study the evolution of some peaks suitable to monitor the hydrolysis and the condensation reaction and the results of the investigation on the 80%TEOS-20%OTES composition are reported here. Since the isopropanol and ethanol (reaction by-product) Raman features are particularly intense, to obtain strong alkoxide Raman features the spectra were acquired on a sol containing an higher Si concentration (2M) with respect to those originally used as protective coatings (0.5 M) and working at pH~5, instead pH~2, to slow down the reaction kinetics and then better follow the changes of the Raman features. The intensity decrease of the TEOS features at 652, 930 and 1090 cm-1 indicates the progress of the hydrolysis reaction. In particular, the symmetric stretching modes of the Si-O bonds of both alkoxides at ≈ 650 cm-1 completely disappear after 10 minutes, indicating that the reaction was completed [3]. The evolution of the Si-O anti-symmetric stretching peak at ≈795 cm-1 can be used to follow the condensation reactions. This mode initially is found to increase in intensity with the number of hydrolyzed alkoxide molecules. Then its intensity decreases since the condensation gives the formation of siloxanic -Si-O-Si- groups [4]. This is confirmed by the intensity of the 1047 cm-1 peak, attributed to

RAA 2013 114 P29 the asymmetric stretching motions of the Si-O-Si bonds, which increases over the reaction time. The process was followed for 48 hours: the typical large silica band appears between 250–450 cm- 1, together with changes –in intensity and position– in the high frequency region concerning the stretching motions of the C–H groups. The Raman monitoring of the sol-gel process to follow the hydrolysis and condensation reactions proved to be a fast and easy way to understand the changes occurred in the system over the reaction time.

References [1] I. Pallot-Frossard, A. Bernardi, R. Van Grieken, S. Rolleke, M. Verità, Rivistadella Stazionesperimentale del Vetro. 2005, 35, 75–83. [2] O. Chiantore, M. Lazzari, Polymer. 2000, 42, 17–27. [3] I. G. Marino, P. P. Lottici, D. Bersani, R. Raschella, A. Lorenzi, A. Montenero, Journal of Non-Crystalline Solids. 2005, 351, 495–498. [4] M. Gnyba, M. Jędrzejewska-Szczerska, M. Keranen, J. Suhonen, Proceedings, XVII IMEKO World Congress, June 22–27, 2003, Dubrovnik, Croatia, 2003, 237.

115 Book of Abstracts P30

Possible differentiation with Raman spectroscopy between synthetic and natural ultramarine blues. Comparative analysis with the blue pigment of a painting of R. Casas (1866-1932)

A. R. De Torres,1 S. Ruiz-Moreno,1 A. López-Gil,2 P. Ferrer,2 M. C. Chillón2

1 Universitat Politècnica de Catalunya, Barcelona, Spain, (34) 934016443, [email protected], [email protected] 2 Actio Arte y Ciencia, Barcelona, Spain, (34) 934054608

This work deals with the possible differentiation among several synthetic ultramarine blue pigments, which in turn, are compared with a natural ultramarine blue (lazurite) from Afghanistan. For that purpose, three synthetic pigments manufactured by Nubiola (trademark) have been characterized with Raman spectroscopy. The fundamental molecular structure of these synthetic pigments is

(Na8-xAl6-xSi6+xO24)Sy where 0 ≤ x ≤ 1 and 2 ≤ y ≤ 4.

The results have demonstrated that it is possible to detect appreciable differences in both, the Raman frequencies and relative intensity values. However, it is remarkable that none of the obtained spectra matches with the lazurite mineral spectrum. On the other hand, one of the synthetic pigments (NUB1) shows a Raman spectrum which is identical to the measured in the blue areas of an easel painting by the modernist Catalonian painter Ramón Casas i Carbó (Barcelona, 1866-1932).

Therefore these results indicate that it seems possible to discern among natural ultramarine blue and its several synthetic imitations. In figure 1, the obtained spectra for synthetic pigments, blue painting and lazurite are shown: NUB1 and R. Casas; NUB2; NUB3; and lazurite. Note that NUB1 and R. Casas are identical.

Figure 1. Raman spectra of three synthetic ultramarine pigments (NUB1, NUB2 and NUB3) and Raman spectrum of lazurite from Afghanistan. The Raman spectrum obtained in the R. Casas painting coincides with NUB1 spectrum.

RAA 2013 116 P30

The observed Raman shifts and the variations in the relative intensities are especially relevant in the - Raman bands associated with the S3 anion, which is the responsible chromophore of the blue hue in these pigments. Positional differences about 2-3 cm-1 and variations close to 60% in intensity have been observed.

The present results have been obtained with a He-Ne red laser (633 nm.). Future experimental results will be carried out analyzing other natural ultramarines and, on the other hand, using another laser (Ar green laser, 514 nm.) in order to extract more conclusions about the possible spectral differentiation proposed here.

Acknowledgements This work has been supported by the Spanish Government project (CICYT, TEC 2009-07855), entitled ‘Investigation and Optimization of Raman Spectroscopy Applied to the Direct Analysis of the Cultural Heritage.’

117 Book of Abstracts P31

Raman monitoring of the polymerization reaction of a hybrid protective for wood and paper

Laura Bergamonti,1 Claudia Graiff,1 Clelia Isca,1 Giovanni Predieri,1 Danilo Bersani,2 Pier Paolo Lottici2*

1 Chemistry Department, University, Parma, Italy, +39 0521 905430, [email protected] 2 Physics and Earth Sciences Department, Parma, Italy, +39 0521 905238, [email protected]

The cellulosic materials (wood and paper) but also stone materials, exposed outdoors or in high humidity conditions, are subject to various forms of degradation, including the biological deterioration caused by various microorganisms such as bacteria, fungi and algae. Here we present a monitoring by micro-Raman spectroscopy of the polymerization reaction of a new polymer for the protection of materials of interest for cultural heritage, in particular for lignocellulose. The polymer is a hybrid organic-inorganic polyamidoamine (PAA) functionalized with hydrophilic and siloxanic groups. The polyamidoamines are polymers characterized by the presence of amide and tertiary amino groups, obtained by polyaddition of bis-acrylamides with primary and secondary mono/ di- amines in protic polar solvents. The mechanism of addition of the amine to the acrylamide double bond is a nucleophilic addition 1-4 to the α, β unsaturated carbonyl compound. To monitor the progress of the reaction of polymerization with Raman spectroscopy, we have followed the decrease of the intensity of the C=C bond stretching vibration peak at 1629 cm-1 of bis-acrylamide, which should disappear when the polymerization reaction is complete, with respect to the peak intensity of the carbonyl group stretching mode at ≈ 1650 cm-1. To optimize the reaction conditions between the bis-acrylamide and the primary amine, with and without siloxanic functionality, molar ratio of the reactants, type of solvent (water, methanol, ethanol), order of mixing of the reactants (amine, amide), reaction temperature (25 °C, 55 °C, 93 °C) have been varied. Raman spectra indicate that the most favorable conditions are obtained when the solutions are concentrated, when methanol is used as solvent and when bis-acrylamide is added dropwise to the solution containing the primary amine. The proposed polymer is being tested as a useful tool for the protection of wood or paper artifacts of interest for Cultural Heritage conservation.

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Reference Raman data of the artist palette – tool for in-situ investigation of J. Matejko (1838-1893) paintings

Iwona Żmuda-Trzebiatowska,1* Mirosław Wachowiak,2* Mirosław Sawczak,1 Gerard Śliwiński1

1 Photophysics Dept., The Szewalski Institute, Polish Academy of Sciences, Gdańsk, Poland, +48 58 6995313, [email protected] 2 Dept. of Conservation and Restoration of Modern and Contemporary Art, N. Copernicus University, Toruń, Poland

During last two decades the studies performed with the usage of Raman technique on historical objects, materials and also on artist’s techniques and production technologies of the past result in elaboration of reliable analytical procedures. Depending on the analyzed material and information of interest the Raman data are often complemented by additional examinations of the elemental and/or compound composition and structure. Such an approach is well proven in the research on historical materials and a variety of combinations of the Raman spectroscopy with other techniques is reported.[1] This also ensures marked improvement of the confidence level of the results. In the analysis of results the reference spectra accessible in the form of databases play an important role. These data enable identification and discrimination of substances using the unique characteristics of the Raman spectrum of a given material. It can be observed, that the need for dedicated spectral data results in works devoted to specific historical objects, collections, materials and model materials. In particular, the Raman identification and reference spectra of historical paints represent an area of continuous research progress.[2] However, literature data indicate that most of the Raman studies on pigments are devoted to identification and characterization of materials used in ancient artworks. Only few published works are dealing with modern paintworks from the period of XIX-XX c. performed with the use of newly synthesized organic and inorganic materials in addition to the traditional ones. For example, recent results of the study on crystalline phases of the blue dye copper phtalocyanine indicate on dating possibility.[3] In the work of Casadio et al the presence of synthetic pigments in modern paintings is concluded from the comparative Raman analysis performed with the use of the reference cobalt-based green and blue pigments.[4] Studies published so far, confirm that reliable identification and characterization of recent paint materials are needed and the research on paint components and compositions can be effectively performed by the Raman study combined with other complementary techniques. The objective of this work is to provide tool enabling non-destructive, in-situ investigation of the paintings collection of J. Matejko (1838-1893). It bases on the assumption that reliable identification of the historical paint materials can be obtained by comparative analysis of spectra from dedicated database with these obtained non-invasively from the original paintings. In order to create the spectral database the detailed analysis of the mix of original paint material preserved from the period of 1880- 1893 and stored in the National Museum in Cracow is performed. The Raman spectra of the paints of J. Matejko are treated as the key spectroscopic signatures and are complemented by additional measurements using techniques such as XRF, XRD, FTIR and NIR, selected in dependence on the kind of materials (pigments, fillers, organic dye carriers, etc). Data from elemental analysis are used for identification of pigments such as: ochre, cerulean blue, cobalt blue, emerald green, vermillion, chrome yellow and strontium yellow and the presence of ultramarine and malachite in the paint material and also admixtures of the bees wax to medium are revealed in agreement with Raman spectra. For paints

119 Book of Abstracts P32 containing organic dye and also for binders the FTIR measurements are performed, too. So the usage of individual pigments as well as pigment mixtures provided by producers is confirmed. From the presence of characteristic trace elements the origin and production methods of the paint components are concluded. New information on fillers, dye carriers (Al or Sn compounds) and the binding media are obtained. Results obtained so far contribute significantly to the knowledge on the workshop of the XIX c. artist. Moreover, it is confirmed in agreement with literature that the approach based on the use of dedicated Raman reference data complemented by results obtained by other appropriate spectroscopic techniques enables non-destructive, precise identification of the original paint materials.

Acknowledgements This work has been financially supported by the DS research grant 030295 from the Faculty of Mechanical Engineering, Gdańsk University of Technology and via project ’19 century pigments’ 2012/05/D/HS2/03385 of the NCN -National Science Centre of Poland.

References [1] L. Burgio, R. J. H. Clark, Spectrochimica Acta Part A, 2001, 57, 1491–1521. [2] F. Rosi, J. Raman Spectrosc. 2004, 35, 610–615. [3] C. Defeyt, J. Raman Spectrosc. 2012, 43, 1772. [4] F. Casadio, et al., J. Raman Spectrosc. 2012, 43, 1761.

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Spectroscopic characterization of the Illuminated Manueline Charters of Marvão and Lousã

Cristina Barrocas Dias,1* Ana Claro,1 Sara Valadas,1 Lília Esteves,2 Maria José Mexia,3 Jorge Oliveira,4 Teresa Ferreira,1 António Candeias1,2

1 HERCULES Laboratory, Évora University, Portugal, 351 266745300, [email protected] [email protected], [email protected], [email protected]; [email protected] 2 José de Figueiredo Laboratory, Rua da s janelas Verdes, Lisbon, Portugal 3 Torre do Tombo National Archive, Alameda da Universidade, Lisbon, Portugal 3 History Department/ Évora University, 351 266745300, [email protected]

King D. Manuel I of Portugal in the beginning of the 16th century updated the public life regulation of the realm, renovating the town and villages foral charters which had been issued in the 12th century. The updated codices were written on parchment in contemporary language with gothic style characters, and the folios Incipit illuminated with precious ornaments. These new documents expressed the authority of the realm, and sometimes, also reflected the importance of the village or town. Previous studies on the Manuelin charters of Vila Flor [1] and Sintra [2] have shown that different materials have been used for their production. The study presented here involves the material analysis of the Marvão and Lousã Charters. These two villages had different historical importance in the 16th century: while Marvão administered a vast and strategic geographic area, Lousã was a smaller village located close to Coimbra, which was the main administrative centre of the region. Maybe due to their difference in terms of administrative importance, the codices of Marvão and Lousã have a different typology of the illuminated folios Incipit. The Marvão Charter presents a shield crowned with the royal arms flanked by two armillary spheres, with the name Dom Manuel painted bellow in a banner and a large border in the lower part of the page painted with white carnations. The Lousã presents a more sober decoration with a gilded initial D and a decorative vegetative border with red and blue flowers (version A); a second copy of the Lousã charter (version B), with a similar decoration, was also available and subject to study. This version B of the Lousã Charter was in poor conservation state when compared to the version A of the document. Micro sampling was performed with a micro chisel of the different colours of the folios Incipit of Marvão and the two copies of the Lousã Charters. The size of the micro samples was around 100 micrometers. The samples were subjected to various analytical techniques namely, micro-Raman, micro-FTIR, SEM- EDS and HPLC-DAD in order to identify the pigments and the binding media used in their making. A large number of different pigments could be identified in the Marvão compared to the Lousã Charters. In both Marvão and version A of Lousã Charters, analysis enabled the identification of azurite and malachite in the blue and green areas. Lighter hues were obtained with the addition of lead white, while carbon black was added to obtain darker hues. Red colours were obtained mainly with vermillion, but in several reddish areas, brazilwood lakes could be identified by HPLC-DAD. Silver dust was added to the paint used in the bluish background of the armillary spheres of the Marvão Charter and in some silvered areas of the version A of Lousã Charter, while gold dust was also found in some painted areas of both documents. The yellows, identified only in the Marvão Charter, were obtained with massicot, lead-tin yellow Type I and II and ochre. Both polysaccharides and proteins were identified as binders in different colours and calcium carbonate was detected in some cases as extender. Carbon black and iron gall ink was used for the writing.

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Surprisingly, the analysis of the samples collected in the version B of the Lousã Charter revealed the use of some pigments that could not be found in the 16th century. For example the blue colours were obtained with azurite and ultramarine blue (likely synthetic); green was obtained with prussian blue and a non-identified yellow pigment. In the golden areas, brass powder was used instead of gold powder and in the areas where silver powder had been used in version A, a tin alloy powder was used to make the paint used in version B. The results obtained indicate that the materials used to make the Marvão Charter and version A of the Lousã Charter are consistent with their production on the 16th century and some have already been described in previously analysed charters. The version B of the Lousã Charter was probably restored in the XIX century because the parchment and some of the materials used are similar to that of the version A. It is known that more than one copy was made in the 16th century, but in most cases only one copy survived. The version B of the Lousã Charter is most likely the copy that was handled on a regular basis, leading to deterioration of the manuscript and its restoration in the 19th century.

References [1] L. Moura, M. J. Melo, C. Casanova, A. Claro, “A study on Portuguese manuscript illumination: The Charter of Vila Flor (Flower town), 1512”, J. Cultural Heritage. 2007, 8, 299–306. [2] M. Manso, A. Le Gac, S. Longelin, S. Pessanha, J. C. Frade, M. Guerra, A. E. Candeias, M. L. Carvalho, “Spectroscopic Characterization of a Masterpiece: The Manueline Foral Charter of Sintra”, Spectrochimica Acta Part A. 2013, 105, 286–296.

RAA 2013 122 P34

Materials and gilding techniques on plasterwork in the Alhambra (Granada, Spain)

Ana Domínguez Vidal,1* María José de la Torre López,2 Domene Ramón Rubio,3 María José Campos Suñol,4 Ulrich Schade,5 María José Ayora-Cañada1

1 Department of Physical and Analytical Chemistry, University of Jaén, Spain, [email protected], [email protected] 2 Department of Geology, University of Jaén, Spain, [email protected] 3 Conservation Department, Council of The Alhambra and Generalife, Granada, Spain, [email protected] 4 OTRI, University of Jaén, Spain, [email protected] 5 Infrared beamline IRIS, BESSY – II Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany, [email protected]

A complete study of the decayed gilded decorations of the stalactite vaults of the Hall of the Kings in the Nasrid Palace of the Lions in the Alhambra complex (Granada, Spain) has been carried out. A combination of analytical techniques capable of elemental, microstructural and molecular characterisation was used for the identification of ancient gilding technology. Sampling was performed on the remnants of golden decorations in the seven vaults of the Hall of the Kings. The samples were analysed in order to characterize both the substrate and the finishing layers: traces of gilding showing golden, black and yellow-orange areas as well as areas of violet tonality that according to their spatial disposition seem to have been golden before. The analytical techniques employed were petrographic microscopy, Raman micro-spectroscopy, FTIR micro-spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectrometry (FESEM-EDX). Raman spectra for raw samples (without any sample preparation) and thin cross sections were recorded on a Renishaw (in Via Reflex) spectrometer coupled to a Leika microscope. FTIR spectra were obtained with a Nicolet spectrophotometer coupled to a Nicolet Continum IR microscope using either the conventional IR source or synchrotron radiation. In both cases FTIR transmission spectra were collected from the samples placed on a diamond cell viewed through the microscope system. Micrometric samples were first placed and pressed in the diamond cell, and then only one window of the cell was used for the measurement. A Zeiss SUPRA40VP and LEO 1430-VP were used to obtain images in both secondary electron (SE) and backscattered electron (BSE) modes. The use of variable pressure enabled the investigation of non-conductive specimens in their natural uncoated state. In this way, the samples can be investigated by other spectroscopic techniques. Three different techniques of gilding and false gilding have been characterized: a) application of a very thin gold leaf (1-2 µm) using a proteinaceous binder to fix the gold leaf directly to the finishing layer of the plasterwork substrate (Figure 1a), b) false gilding using a thicker tin leaf (10-13 µm) tinted to look like gold by means of a varnish based on a natural resin (Figure 1a), and c) gilded tin which consist of a laminated structure with a thin layer of gold (1 µm) over a thicker tin layer (10-13 µm). (Figure 1b).

Tin layers appeared very altered in some areas showing an expansion in volume (see figures 1a and 1b) leading to thickness about 50 µm. In these areas Raman spectroscopy clearly identified SnO with bands at 113 and 203 cm-1. In addition, other alteration products like calcium oxalates have been detected, possibly as a result of the degradation of organic materials. The intense fluorescence from the organic layers made impossible the recording of any useful Raman spectrum. Organic materials were

123 Book of Abstracts P34 successfully identified by means of FTIR. In conclusion, the present study highlights the importance of the use of multi-analytical approaches in the cultural heritage field and in particular, for the identification of ancient gilding technology. SEM- EDX analysis provided the base knowledge of the metal leafs and their spatial disposition; μFTIR spectroscopy was prevalently used to examine the composition of the organic materials employed as adhesive and varnish and Raman microspectroscopy provided insight into the different degradation compounds formed.

Acknowledgements This work was financed by the research project CTQ2009-09555 from the Ministry of Science and Innovation. The Council of the Alhambra and Generalife, PAIDI Research Groups FQM 363 and RMN 325 are also acknowledged for supporting this project. The Helmholtz-Zentrum Berlin für Materialien und Energie is thanked for beamtime and travel expenses assigned to proposal 2012_120151.

Figure 1. SEM-BSE (backscattered electron mode) images of thin cross sections showing a.) a sequence of layers from bottom to top: gold, altered tin, organic layer, and gold layer and b.) from left to right: two laminated structures formed by a thick tin layer covered by a thin layer of gold and a final gypsum layer applied to cover the altered gilded decoration which macroscopically looks violet.

RAA 2013 124 P35

Characterization of gypsum and anhydrite ground layers from 15th and 16th century Portuguese painting by Raman Spectroscopy, Micro X-ray diffraction and SEM-EDS

Vanessa Antunes,1* António Candeias,2,4 ,Stéphane Longelin,3 Ana Isabel Seruya,3 Maria Luísa Carvalho,3Maria José Oliveira,2 João Coroado,5 Luís Dias,4 Vitor Serrão1

1 Instituto História da Arte da Faculdade de Letras da Universidade de Lisboa (IHA-FLUL), Alameda da Universidade, Lisboa, Portugal,[email protected],[email protected] 2 Laboratório José de Figueiredo da Direcção-Geral do Património Cultural (LJF-DGPC), Lisboa, Portugal, [email protected], [email protected] 3 Centro de Física Atómica da Universidade de Lisboa (CFA-FCUL), Lisboa, Portugal, [email protected], [email protected] 4 Centro HERCULES, Universidade de Évora, Portugal, [email protected] 5 Instituto Politécnico de Tomar (IPT), Tomar, Portugal, [email protected]

This work intends to characterize the execution techniques of Portuguese painting ground layers from 15th and 16th centuries (1450-1600), taking into consideration the chosen materials, its composition, manufacturing processes, application, polishing, under-drawing and priming. The use of gypsum in these layers is common in the Iberian Peninsula, either as natural resource, either as evidence on Portuguese and Spanish paintings1, prepared generally from calcium sulphate and animal glue. Besides the common elements from the various painting workshops at the time, gypsum and anhydrite ground layers have specificities that allow characterizing different compounds. The clarification of the specific methodologies and materials used in each workshop can be related with the contemporary treatises. The analysis and interpretation of ground layer techniques is commonly the result of several incomplete instructions brought by different treatises,such as several authors suggest 2-7. The few Portuguese treatises and manuscripts describing the process of gypsum transformation and preparation for ground layers in painting started to be written in 17th century8-10. Based in this complementary information, although those treatises mention the same animal glue binder, differences on the choice of the type of filler material can be defined, between regional or cosmopolitan workshop, and perhaps the influences of the geographical conditions. We may isolate and define those differences and similarities through a chemical, geographical and geological approach of ground layers that constitute the paintings Workshop of Viseu, Coimbra, Lisboa and Évora. By standardizing the ground layers for each painting workshop, we will try to find scientific confirmation for the identification and origin of the paintings, as announced by Art History.

Experimental procedure Cross-sections were prepared and examined initially by optical microscopy and SEM imaging (SE and BSE modes), to identify different layers of gypsum and anhydrite, the number of ground and paint layers, granullometry, layer thickness, polishing between layers, priming, etc. Micro-samples were observed with a Leitz Wetzlar optical microscope coupled with digital camera Leica DC 500equipped with visible light, dark and light field. To identify elemental composition of the inorganic compounds a SEM-EDS Hitachi 3700N scanning electron microscope coupled with a Bruker XFlash 5010 SDD detector. The current used was 20 kV. In gypsum and anhydrite ground layers Ca and S were identified as major constituents and trace elements

125 Book of Abstracts P35 such as Sr, Al, K, Fe, Mg, Si, P and Na were also detected. Strontium might be associated to celestite in calcium sulphate while Al, K, Fe, Si, P and Na can be related to aluminosilicates and Mg, Ca and Fe to dolomite. Micro-Xray diffraction was performed by a commercial Bruker AXS D8 Discovery diffractometer with Cu K radiation, Gadds detector, angular range8–70º and a step of 0.02º. The EVA software was used for the identification of the phases. From these results it was possible to determine the relative percentage of gypsum and anhydrite in the studied ground layers. However, it was not detected any compound associated to the elements Mg and Fe, identified by EDS as trace elements, probably because they arepresent in quantities lower than the detection limit of the equipment. The Raman spectra were measured on a Raman spectrometer Horiba Xplora Confocal Micro-Raman, using a laser diode source operating at a wavelength of 785 nm. The laser power applied to the sample was 2-5 mW. Each spectra for typical times of 2 s with 50 scans using a diffraction grating of 1200 lines/ mm that gives a resolution of 4 cm-1. Pictures have been taken with a BX41 microscope (Olympus) using x100 magnification and equipped with a Ueye 1640 camera. Measurements confirmed the existence of anhydrite and gypsum. Furthermore the compounds containing the trace elements already detected by SEM(EDS) were also identified : silicate minerals of calcite (CaCO3), dolomite (CaCO3.MgCO3) with

Feand sulfate mineral celestite (SrSO4).This last compound, existing in very low levels in gypsum and anhydrite ground layers, occurredin two different ways: whether as celestite grains or celestite grains covered with lead.

Conclusions This preliminary study allows us to make a first comparison between different Portuguese workshops based on the celestite and dolomite patterns, even though the painters of the last decade of the 16th century worked in various regions of Portugal.It is our purpose compare the obtained results with treatises and specialized bibliography and define the Portuguese integration in the peninsular context at the time, looking to set national and peninsular patterns.

Acknowledgements The authors wish to acknowledge the Fundação para a Ciência e Tecnologia (FCT/MCTES - PIDDAC) for financial support (PhD grant SFRH / BD / 37929 / 2007 , science andtechnology grant SFRH / BGCT / 51652 / 2011 and project PTDC/EAT-HAT/100868/2008) trough the program Ciência e Inovação POCI2010 and QREN-POPH – typology 4.1 (co-participated by the European Social Fund (ESF) and national funds MCTES), as well as the institutions IHA-FLUL, LJF-DGPC, IPT, HERCVLES Lab.- Évora and CFA-FCUL.

References [1] S. S. Gómez et al., Contribution to the study of grounds for panel painting of the Spanish School in the fifteenth and sixteenth centuries. in Painting techniques, history, materials and studio practice, contributions to the Dublin Congress, 7-11 September 1998 London, International Institute for Conservation of Historic and Artistic Works, 1998. [2] L. Carlyle et al., Historically accurate ground reconstructions for oil paintings, in Preparation for Paintings, The Artist’s Choice and Its Consequences J.H. Townsend, et al., Editors. Archetype Books, 2008, p. 110–122. [3] L. Carlyle, M. Witlox, Historically Accurate Reconstructions of Artists’ Oil Painting Materials. Tate’s Online Research Journal, Tate Papers ©, 2007. [4] P. Hendy, A. S. Lucas, The ground in pictures. Museum, 1968, XXI(4), p. 245–276.

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[5] S. Santos Gómez, Las preparaciones de yeso en la pintura sobre tabla de la Escuela Española, D. d. P. Facultad de Bellas Artes, Editor. Universidad Complutense de Madrid, Servicio de Publicaciones, Madrid, 2006. [6] M. J. Gonzalez Lopez, Estudio de las preparaciones de pintura sobre soportes de tela y tabla, Caracterizacion de sus principales componentes, comportamiento y factores de deterioro, in Bellas Artes, Universidad de Sevilla: Sevilla, 1992, p. 792. [7] S. S. Gómez, M. S. A. Moya, and A. Rodriguez, Reconstruction of documented preparation methods for gesso grosso and gesso sottile in Spanish School panel paintings in Art Technology – Sources and Methods, S. Kroustallis, et al., Editors. Archetype Publications: London, 2008, p. 196. [8] P. Nunes, Arte da Pintura, Symmetria e Perspectiva, in fac-simile da edição de 1615 com um estudo introdutório de Leontina Ventura, 1982, L. Ventura, Editor. Editorial Paisagem: Porto, 1982. [9] F. De Holanda, Da pintura antiga, introd. notas e comentários de José da Felicidade Alves, J.d.F. Alves, Editor, Livros Horizonte: Lisboa, 1984, p. 128. [10] P. Monteiro, L. Afonso, Fontes para o estudo dos pigmentos na tratadística portuguesa,da Idade Média a 1850, in Artis, revista do Instituto de História da Arte da Faculdade de Letras da Universidade de Lisboa, Instituto de História da Arte da Faculdade de Letras da Universidade de Lisboa, Lisboa, 2007, p. 161–186.

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Identification of deteriorated pigments on wall paintings from Lutrovska klet, Sevnica, Slovenia, using Raman spectroscopy and SEM-EDS

Katja Kavkler,1* Ajda Mladenovič,1 Ana Mladenovič2

1 Restoration Centre, Conservation Centre, Institute for the Protection of the Cultural Heritage of Slovenia, Ljubljana, +386 1 2343 168, [email protected] 2 Slovenian National Building and Civil Engineering Institute, Ljubljana, Slovenia, [email protected]

In 2010 conservation and restoration works were started on a renaissance wall painting in Lutrovska klet (cellar) at Sevnica Castle, in Slovenia. On the east side of its interior, the ground floor of the outbuilding, which served as an oratory for Lutherans during the Reformation, is completely painted. The painting was done in secco (tempera) technique and has severely deteriorated due to environmental factors. The causes for its present condition are the following: high relative humidity, salt crystallization, temperature fluctuations, and improper use of the room in the past, when it served as a wine cellar and warehouse. Unfortunately, past restoration interventions have caused additional problems, especially due the inappropriate choice of consolidants. Loss of strength of the binder has led to pulverization and flaking of the paint layers, so that a large part of the original layers has been lost. Part of the painting was covered by a greyish veil of gypsum, and microorganisms could be observed as black stains on the walls. Advanced analysis methods were of great importance in the resolving of these problems.

Several samples were taken from the wall painting, from the non-affected as well as from deteriorated areas. The samples were embedded in polyester resin and polished. Cross sections were observed using an Olympus BX60 optical microscope, as well as in a micro-Raman spectrometer and scanning electron microscope, equipped with energy dispersive spectrometer (SEM-EDS). In the case of Raman and SEM-EDS, point as well as mapping analyses were performed.

Raman spectra were obtained using a Horiba Jobin-Yvon LabRam HR800 spectrometer, equipped with a high-stability BX 40 optical microscope, a grating with 600 grooves per mm, and an air-cooled CCD detector. The spectrometer was set up in confocal mode. Spectra were excited with a 785 nm laser.

A low vacuum LV-SEM (JEOL) 5500 LV scanning electron microscope with an OXFORD EDS analyzer was used for mictrostructural and elemental analysis.

Samples from paint layers were taken in different areas – deteriorated as well as non-deteriorated. Wherever possible both samples were taken from the same paint in order to compare differences between unchanged and deteriorated pigments. For the present study four cases were selected – green, blue, light brown and red painting areas. Pigments were identified using point mode micro-Raman spectroscopy. The results showed that in the case of the blue paint layers, smalt and calcite were used as pigments, whereas malachite mixed with lead white, yellow ochre, lead red and calcite was used for the green layers, lead white mixed with lead red, yellow ochre, calcite and probably some organic dyes for the brown layers, and, for the red paint layers, red lead and lead white in the upper layers, whereas vermilion was identified was identified in the lower layers. Further analyses showed that the microstructure and chemical composition of several pigments used

RAA 2013 128 P36 in the analysed painting had been changed. The main reasons for deterioration were the presence of moisture and sulphur compounds in the air, the presence of microorganisms, and the properties of certain less stable pigments. In the smalt, migration of K+ ions was observed by SEM-EDS mapping, which caused discolouration[1], and by optical microscopy. The malachite changed into copper sulphate and copper oxalate, both of which are green in colour and therefore do not change the visual appearance of the painting[2][3]. The colour was not altered by transformation from basic lead carbonate to lead sulphate, both of which are white in colour. On the other hand, lead sulphide, which is a more highly deteriorated product of lead carbonate, is black, and could be observed by optical microscopy and identified in the white layers by Raman spectroscopy[4]. The most visible change in the appearance of the wall painting was a greyish veil over the paint layers. This was the result of changes from calcium carbonate to calcium sulphate. The latter is a soluble salt, which crystallizes on the painting surface, as observed with both SEM- EDS and Raman mapping. The black crusts observed in some areas of the painting are caused by the inclusion of dark dust particles into the calcium sulphate matrix.

Scanning electron microscopy with energy dispersive spectrometry and micro-Raman spectroscopy proved to be useful methods for the classification of the deterioration of pigments and determination of causes for visible changes in paintings. Combining point and mapping analyses provides more information compared to a single method.

References [1] M. Spring, C. Higgit, D. Saunders, Nat. Gall. Tech. Bull. 2005, 26, 56. [2] K. Castro, A. Sarimento, I. Martínez-Arkarazo, J. M. Madaraiga, L.A. Fernández, Anal. Chem. 2008, 80, 4103. [3] S. Švarcová, D. Hradil, J. Hradilová, E. Kočí, P. Bezdička, Anal. Bioanal. Chem. 2009, 395, 2037. [4] G. D. Smith, L. Burgio, S. Firth, R. J. H. Clark, Anal. Chim. Acta. 2001, 440, 185.

129 Book of Abstracts P37

Characterization of Middle Age mural paintings: in-situ Raman spectroscopy supported by different techniques

Marco Veneranda,1 Mireia Irazola,1 Marta Díez,1 Ane Iturregui,1 Julene Aramendia,1* Kepa Castro,1 Juan Manuel Madariaga1

1 Dept. Analytical Chemistry, University of the Basque Country (UPV/EHU), Bilbao, Spain, +34 946018297, [email protected]

The conservation of wall paintings is closely related with the action of external agents. For example, the water present in the soil can ascend through the walls of a building by capillarity. These infiltrations imply the presence of dissolved salts which under certain conditions can give rise to white efflorescences. [1] These efflorescences cause mechanical stress, chemical alterations and, finally, aesthetical problems. [2] Specially in the past, through conservative interventions these problems were generally hidden under new painted layers. In this sense, degradation processes and repaints become the main causes of the wall paintings´ original essence lost. In this work several wall paintings from two different churches in Alava (Basque Country, Spain) were analysed: one from the 14th century located in “La Asunción” Church (Alaiza) and the other one from the 15-16th century located in “San Esteban de Ribera” (Valderejo). The molecular and elemental analyses carried out in this study try to survey the original materials used by the artists, to identify the pigments used in ulterior repaints and to classify the main products formed due to the different sources of deterioration. For this aim, several analyses were carried out: portables Raman and EDXRF spectrometers were used in situ in order to obtain a first screening of the composition and the conservation state of the wall painting and at the same time, to identify the most interesting areas for sampling. The EDXRF device allowed evaluating the elemental composition of mural paintings, supporting in this way the Raman data. The laboratory analysis of the collected samples was carried out with ionic chromatography which enabled a more exhaustive characterization of the specimens and, thus, a more comprehensive diagnosis of the affection. The ultra mobile B&WTEK InnoRam spectrometer used for in situ analyses is provided with a 785 nm excitation laser and a Peltier cooled CCD detector. At first the spectra were acquired at lower laser power, and then it was increased until a good signal-to-noise ratio was obtained but avoiding the thermo-decomposition. To support the Raman data a hand-held EDXRF portable analyzer XMET5100 (OXFORD Instruments) with a high resolution silicon drift detector was employed. For the laboratory analysis a Dionex ICS 2500 ionic chromatograph with a suppressed conductivity detector ED50 was used. Regarding to Alaiza church, the wall paintings were partially repainted in order to repair decayed areas.

As original components, hematite (Fe2O3) and black charcoal were identified by Raman spectroscopy.

The intonaco was composed by calcite (CaCO3) and gypsum (CaSO4). In the repainted areas ultramarine

blue (Na8-10Al6Si6O24S2-4) and rutile (TiO2) were determined as pigments, in conjunction with barium sulphate, which started to be used in the 19th as a filling material. X-rays fluorescence was successfully used to support Raman analysis in the characterization of several pigments such as chrome yellow

(PbCrO4) and vanadinite (Pb(VO4)3).

Several degradation products such as nitrates (KNO3 and Ca(NO3)2·4H2O) were identified by in situ Raman spectroscopy. By means of ionic chromatography high correlations between chloride and sodium, sulphate and strontium and nitrate and sodium were detected.

RAA 2013 130 P37

Concerning the church of Ribera, the original used pigments were: vermilion (HgS), hematite (Fe2O3), black charcoal, orpiment (As2S3) and lead white ((PbCO3)2×Pb(OH)2). The wall paintings were also partially repainted on the green and yellow areas. In the green colour only phtalocyanine green was found, and in the yellow one, a synthetic yellow belonging to the disazo family was identified; both from the 19th century. It must be highlighted the usefulness of the Raman spectroscopy in the analysis of wall paintings. Apart from the identification of the artworks’ constitutive materials, the main degradations compounds were detected, providing useful data for future restoration projects.

Acknowledgements This work has been financially supported by the CTP (2012-P10) project from the Pirineos work area (Basque Government). M.Veneranda is grateful to the Spanish Ministry of Economy and Competitiveness (MINECO), J. Aramendia and A. Iturregui to the Basque Government and M. Irazola to the Basque Country University for their grants. Authors thanks to Diputaciòn Foral de Alava for all their support.

Figure 1. Raman spectra from Alaiza wall painting, showing the presence of vanadinite, chrome yellow, barium sulphate, gypsum and calcite.

References [1] H. Brocken, G.T. Nijland, Construction and Building Materials, 2004, 18, 315-323. [2] M. Irazola, M. Olivares, K. Catro, M. Maguregui, I. Martínez-Arkarazo, M.J. Madariaga, J.Raman Spectrosc. 2012, 43, 1676-1684.

131 Book of Abstracts P38

Raman microspectroscopic identification of pigments of newly discovered gothic wall paintings from the Dominican Monastery in Ptuj (Slovenia)

Maja Gutman,1* Sabina Kramar,2 Ajda Mladenovič,1 Vlasta Čobal Sedmak,1 Martina Lesar Kikelj1

1 Restoration Centre, Conservation Centre, Institute for the Protection of the Cultural heritage of Slovenia, Ljubljana, Slovenia, +386 1 2343 118, [email protected], [email protected], [email protected], [email protected] 2 Slovenian National Building and Civil Engineering Institute, Ljubljana, Slovenia, [email protected]

In September 2012, during the first reconstruction phase of the Dominican Monastery in Ptuj, precious gothic wall paintings were discovered; a significant find that will greatly contribute to our understanding of artistic and architectural history of the complex. The paintings are located on the south wall of the former sacristy, adjacent to the Chapter house.

The uncovered murals attract attention with their colouring and very interesting figural compositions, depicting a row of horse riders turning towards one another. Particularly intriguing is also the pronounced blue and orange-red pigment, which - together with stylistic features of individual figures - serves as an orientation for dating to perhaps the early 14th century.[1] The depicted procession of riders suggests either the images of certain saintly legends or even a scene of the Magi. Due to the bad condition of the wall paintings, a fairly thick layer of calcium carbonate on the surface and especially because of the complex process of stabilization of the paint layer, it is necessary to proceed with the conservation-restoration works. The colour combinations used along with the determination of the pigments and painting technique as well as distinctive details such as costume, decorative motifs and architectural elements can assist in clarifying the subject matter and dating.

This study presents the application of Raman micro-spectroscopy for the analysis of pigments from newly discovered wall paintings. Several natural as well as synthetic inorganic pigments were identified.

The optical microscope revealed that wall paintings were executed in lime technique, that is mortar and several layers of lime wash, followed by a layer of paint. The identified red pigments were red ochre (hematite), red lead (minium) and vermilion (cinnabar), of which the latter is present in incarnate area, where it is mixed with other pigments, such as red ochre and carbon black. Our observations also confirmed that the red lead pigment, which was mostly used for depicting the garments of figures, degraded into a black or brown plattnerite, resulting in darkening of the red areas.[2]

The blue pigment, which covers the largest area on the wall paintings, was identified as azurite (Figure 1). Despite its relatively high price, azurite was the most important blue pigment in European paintings throughout the Middle Ages and Renaissance because of its texture and surface quality.[3] Similarly, it was quite commonly used in mural paintings in Slovenia during the Middle Ages.[4]

We discovered two different yellow pigments: yellow ochre (goethite) for the yellowish horse and lead-

RAA 2013 132 P38 tin yellow type I, mixed together with red lead, used on the orange dress of one of the figures. However, lead-tin oxide, which was in use between the 13th and the 18th century, was not frequently identified in Slovenian medieval paintings.[4]

Figure 1. Blue paint layer with azurite, one of the most abundant pigments of the wall paintings from the Dominican Monastery in Ptuj (Slovenia). a.) Optical microscope, reflective light. b.) Raman spectrum of azurite (laser 633 nm).

Moreover, two white pigments were also identified; one being lead white (cerussite), applied together with red lead, and the other being lime white (calcite) on a dress on one of the figures. The present Raman microspectroscopic study of pigments from the wall paintings of the Dominican Monastery provides important information on inorganic pigments used in medieval wall paintings in Slovenia.

Acknowledgements This research has been financially supported by the Ministry of Education, Science, Culture and Sport of the Republic of Slovenia, under contract number 3211-05-000545, in the frame of the Conservation- Restoration Project ”the Ptuj Dominican monastery.”

References [1] R. Peskar, Preliminary report on the current progress of conservation-restoration works at the Dominican monastery in Ptuj/ Preliminarno poročilo o dosedanjem poteku konservatorsko-restavratorskih del na Dominikanskem samostanu na Ptuju (in Slovene), available on < http://www.zvkds.si/media/ medialibrary/2012/12/Preliminarno_poro%C4%8Dilo_o_dosedanjem_poteku_konservatorsko- restavratorskih_del_na_Dominikanskem_samostanu_na_Ptuju.pdf > [2] D. Saunders, J. Kirby, Gallery technical bulletin. 2004, 25, 62–72. [3] D. V. Thompson, The materials and techniques of medieval painting. Dover publications Inc.: New York, 1956. [4] A. Križnar. R. Ruiz Conde, P.J. Sancez-Soto, X-Ray Spectrometry, 2008, 37(4), p. 360–369.

133 Book of Abstracts P39

Shot Noise Reduction through Principal Components Analysis

J. J. González-Vidal, 1,2* R. Pérez-Pueyo,1 M. J. Soneira,1 S. Ruiz-Moreno1

1 Signal Theory and Communications Department, ETSETB, Universitat Politècnica de Catalunya, Barcelona, Spain, +34 934016442, [email protected] 2 Institut de Ciències del Cosmos - Universitat de Barcelona, Institut d’Estudis Espacials de Catalunya, Facultat de Física, Barcelona, Spain, +34 934031327, [email protected]

In recent years, the non-destructive technique of Raman spectroscopy has exponentially increased its application in the art world as it is a suitable technique for the characterization of constituent pigmentation in art works [1,2]. This task is important for the cataloguing, conservation and restoration of paintings. In practice, several kind of noises are present in acquired Raman spectra and may hinder the pigments identification. Thus, background correction and shot noise removal are the most important operations for the enhancement of the Raman information in experimental spectra [3- 5]. The aim of this work is to present an algorithm for shot noise reduction with no user input. This novel approach is based on the chemometric technique of Principal Components Analysis (PCA). The presented algorithm was proved in a simulation stage and with experimental cases contaminated with shot noise, obtaining an improved signal-to-noise ratio (see Figure 1). Being fully automated, the presented denoising solution will be potentially useful for preprocessing unknown spectra as input in algorithms of spectral identification [6].

Figure 1. Shot noise reduction example: Original spectrum a.) and denoised spectrum b.).

Acknowledgements This work has been financially supported by CICYT (TEC 2009-07855), entitled – Investigación y Optimización de la Espectroscopia Raman aplicada al análisis directo del Patrimonio Artístico, (IRPA).

References [1] J. M. Madariaga, J. Raman Spectrosc. 2010, 41, 1389 [2] H. G. M. Edwards, Spectrochim. Acta Part A. 2011, 80, 14. [3] M. J. Soneira, R. Pérez-Pueyo, S. Ruiz-Moreno, J. Raman Spectrosc. 2002, 33, 599. [4] C. J. Rowlands, S. R. Elliott, J. Raman Spectrosc. 2011, 42, 370–376. [5] E. Kandjani, M. J. Griffin, R. Ramanathan, S. J. Ippolito, S. K. Bhargavab and V. Bansala,J. Raman Spectrosc., DOI 10.1002/jrs.4232, 2013. [6] J. J. González-Vidal, R. Pérez-Pueyo, M. J. Soneira, S. Ruiz-Moreno, J. Raman Spectrosc. 2012, 43, 1707.

RAA 2013 134 OP21

Raman investigation of artificial patinas on recent bronze, protected by different azole type inhibitors in outdoor environment

Tadeja Kosec,1* Polonca Ropret,2,3

1 National Building and Civil Engineering Institute, Ljubljana, Slovenia, +386 1 2804547, [email protected] 2 Conservation Centre, Institute for the Protection of the Cultural Heritage of Slovenia, Ljubljana, Slovenia, +386 1 23431118, [email protected] 3 Museum Conservation Institute, Smithsonian Institution, Suitland, MD, USA

Bronzes have been widely used for sculptures and other art objects. These artistic bronze objects are usually found covered by a layer of patina. These layers can either be formed spontaneously during the years of exposure or they can be artificially applied by using various solutions of inorganic salts. Acid rain that forms due to the presence of polluting gases may cause extensive damage on the bronze objects and

patina layers. The SO2 and NOx are the main pollutants in urban atmosphere due to the industrial activity and the emission by automotive vehicles. It is well known that in humid air, copper and its high copper alloys (bronze) tend to form an oxide layer (patina). Natural patinas protect copper and its alloys from further corrosion processes. On the other hand, artists have frequently deliberately patinated bronze for visual effects. Thus, it is of great importance to study the patina changing mechanism in order to follow its chemical changes and to predict in advance the likely corrosion processes. Furthermore, the origin of patina and the established degradation state of bronze works of art is also of a great importance for planning proper conservation treatments for these objects as well as for establishing the appropriate environmental conditions for their storage and display. The aim of this study is to investigate the comparison of different protection systems: protection of patinated bronze by two azole type inhibitors, namely imidazole and benzotriazole. For many years benzotriazole was used for protection of copper alloys but due to its toxicity it has to be replaced by some less toxic compound. In this work inhibiting efficiency of benzotriazole as a reference and one environment friendly, newly developed, imidazole based compound were studied. These corrosion inhibitors were applied in the way that our practice confirmed the best effectiveness. Inhibited layers were then protected with a layer that repels water. For the patinas to study, green chloride and green nitrate patinas, applied over the brown artist’s patina, were tested, as well as brown patina and the patina which develops on bare bronze. The Raman study was applied after chemical patination, at different exposure periods and after exposing the samples to outdoor environment for a period of 9 months. At the end of the 9-month exposure, evaluation of protection efficiency was investigated and the comparison of the use of the two different inhibitors is given. The structures of the patinas and of the corrosion products were characterized by Raman spectroscopy, scanning Figure 1. Bronze samples: bare and patinated with electron microscopy (SEM) and X-ray diffraction (XRD). sulphide type patina, nitrate and chloride type patina The end products of each patina and its protection layer are with the two inhibitor system and additional waxing. given.

135 Book of Abstracts OP22

Micro-Raman Investigation on corrosion of Pb-Based Alloy Replicas

Giorgia Ghiara,1* Serena Campodonico,1,2 Paolo Piccardo,1 Carla Martini,3 Patrick Storme,4 Valeria Bongiorno1

1 University of Genoa, Dipartimento di Chimica e Chimica Industriale (DCCI), Genova, Italy, +39 010 3536145, +39 010 3538733, [email protected] 2 INSTM, Genoa 3 University of Bologna, Dipartimento di Ingegneria Industriale (DIN), Bologna, Italy 4 Hogeschool Antwerpen, Royal Academy for Fine Arts, Deparment of Conservation/Restoration of Metals, Antwerp, Belgium

The tendency of a metal to react with the surrounding environment in standard conditions lead to the formation of different known corrosion products. Lead is, as other metals, subjected to corrosion yet its effects are less visible due to the formation of a passivating oxide layer on the metal surface. Lead behavior has been well studied in the past because of its employment for industrial purposes. Even if general knowledge of pure lead corrosive behavior under standard conditions - as wet environments - has been achieved, few are the researches that are dealing with lead and lead alloys behavior under peculiar conditions as presence in the atmosphere of volatile organic compounds (VOCs)[1] The drastic reactivity of lead alloys to VOCs has widely been recognized in recent studies of modern art objects in closed spaces characterized by VOCs rich atmospheres[2] but those researches did not consider the role played by alloying elements in the corrosion process, accelerating or inhibiting corrosion mechanisms. Up to now no researches have been carried out on binary and ternary lead alloys considering Antimony and/or Tin as alloying elements. The employment of microRaman spectroscopy is generally well known for corrosion products of archaeological and artistic materials. Nevertheless it is often replaced with analysis considered more suitable for the investigations as qualitative and quantitative elemental analysis (as Energy Dispersive X-Ray Spectroscopy) or electrochemical analysis (as Open Circuit Potential or potentiodynamic polarization). It is also true that sometimes all the possible information collected by those non-invasive techniques needs confirmation that only a specific type of analysis as microRaman spectroscopy can give. A study conducted by our research group from University of Genoa and Bologna in collaboration with the Artesis Conservation Department of Antwerp on original printing letters from the Platin-Moretus Museum’s Collection consisting of some specific types of Pb-based alloys (with Sb and Sn as alloying elements), seldom studied in the past has brought to outstanding results in this direction. For the occasion Pb alloys - in which Tin and Antimony content was conveniently modified - were reproduced in laboratory and later subjected to specifically created tests following the procedure known as Oddy Test which allows to test art materials. The experimentation consisted of monitoring of Pb based alloys exposed to specific organic acids - as formic and acetic acid – vapours in the time span of few days characterizing corrosion products step by step. Corrosion behaviour was periodically monitored as specimens showed important changes in morphologies and weight: the embrittlement and increase of volume with formation of white and black oxidized compounds spawning from the metal were rather fast representing a serious problem to face once such objects have to be conserved. On such materials microRaman spectroscopy performed in both Genova and Bologna laboratories has given a crucial contribution to the ongoing researches proving itself as an innovative technique not only for the uniqueness of its results and its high detection limits but also for its sensitivity to

RAA 2013 136 OP22 inorganic and organic compounds which in our case were forming on the specimens surface - and were not recognizable with traditional metallographic analyses or electrochemical techniques. In fact this powerful but sometimes underestimated tool not only helped us detect all the corrosion products but allowed us to characterize general corrosion mechanisms affecting this type of alloys giving a wide variety of information which will help estimating further conservation procedures.

Figure 1. Sample 12 - Sb – rich lead alloy replica exploded” after Oddy Test

Figure 2. Micro-Raman Spectrum of a sample showing metallic Sb peaks.

References [1] L. T. Gibson, C.M. Watt, Corrosion Science. 2010, 52, 172–178. [2] J. Tétreault, E. Cano, M. van Bommel, D. Scott, M. Dennis, M. G. Barthés-Labrousse, L. Minel, L. Robbiola, Studies in Conservation. 2004, 48, 237–250.

137 Book of Abstracts OP23

Conservation diagnosis of weathering steel sculptures using a new Raman quantification imaging approach

Julene Aramendia,1* Leticia Gomez-Nubla,1 Ludovic Bellot-Gurlet,2 Kepa Castro,1 Céline Paris,2 Philippe Colomban,2 Juan Manuel Madariaga1 1 Department of Analytical Chemistry, University of the Basque Country UPV/EHU, Bilbao, Spain, +34 946018297, [email protected] 2 Laboratoire de Dynamique, Interactions et Réactivité (LADIR) UMR 7075, CNRS and Université Pierre et Marie Curie, Paris, France

Weathering steel is a material used often in contemporary art. The weathering steel was designed to resist against the atmospheric impact so that no protective coats were needed. In fact, that steel develops a characteristic rust layer that protects the metal reducing the corrosion rate. This rust layer is formed by different iron oxyhydroxides that, together with moisture present in the surface, acts as a barrier that provides the protective ability. The knowledge about the rust layer development is important in order to propose the most suitable protection or restoration method. Kamimura et al[1] came up with the labelled as protective ability index (PAI). PAI takes into account the ratio (α/γ) between the mass of goethite (α-FeOOH) and lepidocrocite (γ-FeOOH), being both main components in the rust layer of weathering steel. The corrosion rate decreases as ratio (α/γ) increases with the exposition time. This index could be a tool to diagnose the conservation state of weathering steel structures. In this sense, the quantification of this index is very useful to assess if some problem of development is being suffered by steel surface. Raman spectroscopy, apart from a qualitative technique, recently is becoming a semi quantitative approach. Therefore, it is a valuable tool for the calculation of the mentioned index in cultural heritage elements. In this work, different weathering steel sculptures from Eduardo Chillida were studied. These - artworks are exposed to a Cl and SO2 rich urban atmosphere in Bilbao, Northern Spain. They present different aesthetical problems on their surfaces, such as detachments of steel chips, discolorations and irregularities. In a previous work,[2] a deep atmospheric attack over these surfaces was described. On the one hand, different atmospheric particles were detected such as calcite, silicates and charcoal and, on the other hand, some sub products formed by reaction of acid gases and steel components. In order to identify if the problems in the development of rust layer could be the cause of the problems on the surface, a semi quantification of different iron oxy-hydroxides was performed over those steel sculptures. The semi quantitative work was carried out by the means of micro-Raman spectroscopy imaging. For this aim, Raman imaging maps were collected using a LabRam HR 800 spectrometer (Horiba Jobin Yvon). This equipment is provided with a 514 nm emission of Ar+ laser and Peltier cooled CCD detector. In order to avoid thermodecompositions and mineral phase changes, the laser power was modulated always adjusting it below 150 µW at the sample. For the mapping under a 100x objective, an Olympus microscope coupled to the spectrometer and an automatically x-y stage were used. The data collection was done using LabSpec software (Jobin Yvon Horiba) and the semi quantitative data was obtained by using a home-made application so-called LADIR-CorATmos (LADIR-CAT)[3]. This software includes pure spectra profiles (the standards) that are used to fit the experimental spectrum. The semi quantitative data were used to perform hyperspectral images. These images help us in the visualisation of how the rust layer is organized, how the different iron oxyhydroxides are disposed along the steel surface and in the calculation of the PAI images.

RAA 2013 138 OP23

In the analyzed samples the heterogeneity was not very high, but in order to be repetitive, several Raman images were performed for each sample. Goethite and lepidocrocite were the most commonly detected mineral phases. However, hematite, akaganeite, magnetite and some atmospheric particles were also identified. As it can be seen in Figure 1, goethite appeared very concentrated in some specific areas of the surface, whereas lepidocrocite used to be the main iron oxide phase in the analyzed steel surface. Obtained maps relate the imaging of sample reactivity, with the PAI values greater than 1 in the higher areas (low rate of corrosion) while the lower ones show PAI values lower than 1, i.e., location of high corrosion rate. Even if these artworks have been exposed outdoors for more than 10 years, results underline that their rust layers seem to be quite still active.

Figure 1. Semi quantitative results for goethite (α-FeOOH) content in a steel chip sample, taken from a moderately degraded sculpture.

Acknowledgements J. Aramendia and L. Gomez-Nubla are grateful to the Basque Government and to the University of the Basque Country (UPV-EHU) for their pre-doc fellowships. We would like to thank the Bilbao Guggenheim Museum, the BBVA bank and the Town Hall of Bilbao for all the support during the analysis of the sculptures. This work has been financially supported by the DEMBUMIES project (ref. BIA2011-28148), funded by the Spanish Ministry of Economy and Competitiveness.

References [1] T. Kamimura, S. Hara, H. Miyuki, M. Yamashita, H. Uchida, Corrosion Science. 2006, 48, 2799. [2] J. Aramendia, L. Gomez-Nubla, K. Castro, I. Martinez-Arkarazo, D. Vega, A. Sanz Lopez de Heredia, A. Garcia Ibañez de Opakua, J. M. Madariaga, J. of Raman Spectrosc. 2012, 43, 1111. [3] J. Monnier, L. Bellot-Gurlet, D. Baron, D. Neff, I. Guillot, P. Dillman, J. of Raman Spectrosc. 2011, 42, 773.

139 Book of Abstracts OP24

Raman study of the salts attack in archaeological metallic objects of the Middle Age: The case of Ereñozar castle (Bizkaia, Spain)

Marco Veneranda,1* Julene Aramendia,1 Silvia Fdez-Ortiz de Vallejuelo,1 Laura García,2 Mikel Neira,3 Kepa Castro,1 Iñaki García,2 Agustín Azkarate,4 Juan Manuel Madariaga1

1 Dept. Analytical Chemistry, University of the Basque Country (UPV/EHU), Bilbao, Spain, +34 946018297, [email protected] 2 Arkeologi Museoa, Bilbao, Spain 3 QarK Arqueología S.L., Vitoria-Gasteiz, Spain 4 Dept. of Geography, Prehistory and Archaeology University of the Basque Country (UPV/EHU), Vitoria-Gasteiz, Spain

In this work, some metallurgical objects from the excavations of Ereñozar castle ruins (XIII century, Basque Country, Spain) have been analyzed. The studied collection is formed by a cooper based ring, ferric and gilded spurs and cooper based decorative objects. The pieces are very heterogenic due to their original composition as well as to the degradation processes that can be seen on their surfaces. In fact, the analyses carried out in this study try to determine the mentioned degradation processes. In the same way, the characterization of the objects tried also to illustrate and explain a historical period, in the field of metallurgy, that due to the scarcity of the investigations carried out until now, still holds many questions.[1] Raman spectroscopy applied in archaeology field has been successfully used to characterise artefacts as well as to reveal decay compounds degradation causes.[2,3] Deterioration of archaeological metallic artefacts buried in soil is often associated with the soluble salts present in those soils, which are directly related to the corrosion products formed or/and deposited on the surfaces of the buried objects. Thus, the analysis of the corrosion layers has great relevance for the survival of such objects. Raman spectroscopy was used in order to assess the degradation degree of the analyzed objects. For this purpose, a Renishaw RA100 and an ultra-mobile B&WTEK InnoRam spectrometer were used, both provided with a 785 nm excitation laser and a Peltier cooled CCD detector. The spectrometers were coupled to a microscope (5x, 10x and 50x objectives). The most used objective was the 50x (spot size around 100 µm) because for this work it was crucial to do microscopic analysis. The laser power was controlled in order to avoid thermo-decomposition. The ultra-mobile Raman spectrometer was used in the measures done in the museum. The devices were calibrated daily with a silicon slice using the 520 cm-1 band. The collected data were treated and interpreted by using Omnic software and homemade databases.[4] To complete the study, soluble salt tests were done with the soils where archaeological artefacts were buried. The quantification of the salts was carried out by means of Dionex ICS 2500 ionic chromatograph with a suppressed conductivity detector ED50 and an Elan 9000 ICP-MS (PerkinElmer), provided with a Ryton cross-flow nebulizer, a Scott-type double pass spray chamber and standard nickel cones. The pieces were analyzed before their restoration, thus the ferric ones were still covered by a thick rust layer composed by different iron oxide phases. It is worth to point out that akaganeite was identify in all the pieces. This iron oxyhydroxide appears in rich chloride environment. The soluble salts quantification confirmed the presence of chloride in the soils. The rust layer formed by iron acts as a protective barrier for the noble metals that are inside the ferric coat. The presence of akaganeite in this layer could decrease its protective ability because it has a channels structure trough which the water

RAA 2013 140 OP24 infiltrations could arrive to the metal core easier. Raman analysis also revealed the presence of several degradation products on the surface of the objects, including, among others, likasite (Cu3NO3(OH)5·2H2O) (figure 1), lead carbonate ((PbCO3)2·Pb(OH)2 ) and Pseudoboleite Pb31Cu24 Cl62 (OH)48.Their presence could be due to the action of soluble salts such as nitrates, nitrites, carbonates and so on. Nitrate and nitrite were detected by ionic chromatography in the soils. Likasite was identified in the ring, concretely, in the place where the linker is placed. Finally, some other salts coming from the soil were detected in the surfaces, such as sodium and magnesium nitrates.

Figure 1. Raman spectrum of likasite (Cu3NO3(OH)5·2H2O).

Acknowledgements This work has been financially supported by the CTP2012-P10 project from the Pirineos work area (Basque Government) and Global Change and Heritage project (UFI11/26) funded by the University of the Basque Country (UPV/EHU). M. Veneranda and J. Aramendia are grateful to the Spanish Ministry of Economy and Competitiveness (MINECO) and to the Basque Government for their grants.

References [1] T. Trojek, M. Hlozek, Applied Radiation and Isotopes. 2012, 70, 1420–1423. [2] S. Réguer, P. Dillman, F. Mirambet, Corrosion Science. 2007, 49, 2726–2744. [3] M. C. Bernard, S. Joiret, Electrochimica Acta. 2009, 54, 5199–5205. [4] K. Castro, M. Pérez-Alonso, M. D. Rodríguez-Laso, L. A. Fernández, J. M. Madariaga, Analytical and Bioanalytical Chemistry. 2005, 382, 248.

141 Book of Abstracts Thursday, September 5

RAA 2013 142 PL3

The Contribution of Archaeometry to Understanding of the Past Effects and Future Changes in the World Heritage Site of Pompeii (Italy)

Juan Manuel Madariaga1

1 Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country UPV/EHU, Bilbao, Basque Country, Spain, +34 946012707, [email protected]

Archaeometry is now considered a self-standing Scientific Discipline, although just some years ago, it was considered as a developing field within the Archaeological Sciences. In the first decades of archaeometric developments, the physical methods were the only applicable, i.e., dating, aerial or ground-based techniques for surveying new archaeological sites, provenance, etc.). The publication of the book “Traces of the Past: Unraveling the Secrets of Archaeology Through Chemistry (by J.B. Lambert, Addison-Wesley, 1997)” encouraged many researchers to apply the knowledge of chemistry (including analytical methods) to the field of Archaeology, broadening the scope of Archaeometry. This Plenary Lecture shows the contribution of the new Archaeometric methods (in-situ spectroscopic analysis, chemometrics, chemical modeling, etc.) to the understanding the past effects and future (Global) Changes on the conservation of the World Heritage site of Pompeii (Italy).

The results presented in this lecture are part of the published material developed in a research program that started 6 years ago. Those results were obtained through chemical measurements on small sample fragments (wall painting, mortars, joint mortars, walls, biofilms on pigmented layer, biofilms on mortars, efflorescence crystals, etc.) processed at the laboratory level and through the spectral information obtained in-situ during the three APUV expeditions (Analitica Pompeiana Universitatis Vasconicae) carried out in 2010 (May), 2011 (September) and 2012 (September). Additionally, samples of volcanic ashes, lapilli, current and foundational soil were analysed, together with the chemical composition of rain water sampled in Pompeii, in order to interpret some “extraneous” results encountered when analysing the composition of the walls and the wall paintings.

Most of the measurements were performed in a non-destructive way. Raman spectroscopy, assisted by other analytical techniques (Infrared spectroscopy and X-Ray Fluorescence spectrometry, were used both in-situ (3 portable instruments) and in laboratory, to identify the compounds present in all the referred samples; in the laboratory also X-Ray Difraction (XRD) and Scanning Electron Microscopy assisted with Energy Dispersive X-Ray Fluorescence (SEM/EDX) were used to complement the observations with the other three techniques. Some other measurements were performed in a destructive way just to obtain the total elemental concentration of the samples (acid digestion followed by ICP/MS quantification) or to obtain the soluble ions present in the samples (water extraction followed by ion chromatography).

The most difficult work in the interpretation of the experimental results was to define which are the original compounds in the walls and wall paintings and which the deterioration compounds promoted by (a) the chemical changes during the eruption and (b) the reactivity between environmental stressors (acidic gases, microorganisms, etc.) and the original materials.

This was accomplished by using chemometrics and chemical reactivity simulations through

143 Book of Abstracts thermodynamic modelling, to explain the whole set of compounds identified in a given scenario. In this methodology, some compounds were tentatively considered as original (calcite for example) that could react with one or several compounds in the surrounding environment (sulphuric acid aerosol), resulting in the formation of a stable compound (gypsum in this case) that must be considered as a deterioration product.

The lecture will show some important case studies conducted during these years of research. The first one is related with the possibilities, advantages and inconveniences of performing in-situ spectroscopic analyses on archaeological remains. Differences in the work in open air, compared to the work in a Museum environment will be presented and discussed. Some results of pigment characterisation, including the degradation of vermilion and red iron oxide will be presented, including the identification of the metallic traces accompanying the original minerals used as pigments, it being extremely important for the correct interpretation of the elemental concentration profiles.

The CO2 attack on non-protected walls will be presented as the greatest decaying phenomenon, accompanied by rain wash of the highly soluble metal bicarbonate salts formed after the acid attack (decarbonation of wall paintings and plaster layers till observation of the arriccio mortar). Only calcium, sodium and potassium carbonate (CaCO3, Na2CO3, K2CO3) were identified by Raman spectroscopy on such degraded walls, therefore all of them can be considered original compounds in the mortars. Here appears one of the most exciting questions to be solved in our research: which are the sources for potassium (and sodium) in the original mortar? Was it included during the process of mortar manufacturing? Was it included in the walls as a consequence of the materials covering the houses after the eruption? Our results and our answer explaining such high potassium values will be given.

Additionally, potassium is important because it has been detected (as nitrate and sulphate) in efflorescence crystals, being one of the most deletorious compounds in the wall painting decay. Different climate conditions were encountered during such field campaigns, allowing us to consider also the climatic variable in the analysis of the entire information we have recorded during these years. This was very important because different types of efflorescence were observed (crystals being two to five millimetres long) in the same location (wall with or without paintings) during the three years.

Other highly damaging compounds systematically detected were, apart from gypsum (CaSO4.2H2O), thenardite (Na2SO4), mirabillite (Na2SO4.10H2O), aphthitalite (K3Na(SO4)2) and syngenite (K2Ca(SO4)2.

H2O), detected in areas near the presence of modern mortars and cements used in past restoration processes.

Acknowledgements I would like to thank the researchers U. Knuutinen, M. Maguregui, K. Castro, I. Martinez-Arkarazo, S. Fdez-Ortiz de Vallejuelo, A. Giakoumaki and A. Pitarch, for their engagement in the projects developed under the APUV activities, as well as to Dr. A. Tammisto, director of the EPUH expeditions, who gave us the possibility to access the research area of Insula IX,3. The administrative and technical facilities given by the Soprintendenza Speciale per I Benni Archeologici di Napoli e Pompei, during our studies in the Archaeological Site of Pompeii and the National Museum of Archaeology of Naples, is acknowledged. This work was financially supported by the projects DEMBUMIES (ref.BIA2011-28148, Spanish MINECO) and Global Change and Heritage (ref. UFI11-26, funded by the UPV-EHU). The accompanying actions CTQ2010-10810-E (MINECO), AE11-27 (UPV-EHU) and AE12-32 (UPV-EHU) supported the expeditions APUV2010, APUV2011 and APUV2012, respectively.

RAA 2013 144 OP25

Raman spectroscopy applied to the study of Cretaceous fossils from Araripe Basin, Northeast of Brazil

Paulo T. C. Freire,1* Francisco E. Sousa-Filho,2João H. Silva,3 Bruno T.O. Abagaro,1 Bartolomeu C. Viana,4 Gilberto D. Saraiva,5 Olga A. Barros,6 Antonio A.F. Saraiva6

1 Departamento de Física, Universida de Federal do Ceará, Fortaleza, Brazil, +55.85.33669906 [email protected] 2 Departamento de Física, Universida de Regional do Cariri, Avenida Leão Sampaio S/N, Juazeiro do Norte, Brazil 3 Universida de Federal do Ceará – Campus Cariri, Juazeiro do Norte,Brazil 4 Departamento de Física, Universida de Federal do Piauí, Teresina, Brazil 5 Faculdade de EducaçãoCiências e Letras do Sertão Central, Universidade Estadual do Ceará, Quixadá, Brazil 6 Laboratório de Paleontologia da Universida de Regional do Cariri - LPU, Rua Cel. Antônio Luiz, Crato, Brazil

In the Northeast of Brazil there is an important paleontological region characterized by the occurrence of several types of Cretaceous fossils with exceptional conservation, the Araripe Basin [1] (meridians 38° 30’ and 40° 50’ W longitude of the Greenwich and parallels 7° 05’ to 7° 50’ S latitude). In this work we present Raman spectroscopic data on fossil from two different formations of Araripe Basin: Ipubi and Crato Formations. In the Crato Formation, many fossils of plants were identified: flowers, fruits, roots, stems, and seeds of different groups. The preservation of such fossils involved diverse mechanisms such as calcification, limonitization, goetization and sometimes carbonization. In the Ipubi Formation there are diverse fossil species, in special, fishes and plants. In the present work we show Raman spectra of plants from the Crato Formation, as well as, from the specie Brachyphyllumcastilhoi from the Ipubi Formation. Additionally, from the substances found in the fossils, we discuss the possible fossilization processes and the environment of the Cretaceous Period in the two geological formations. Raman spectra were collected with a triple-grating spectrometer in the subtractive mode using a JobinYvon, T64000 equipment. A microscope lens with a focal distance of f = 20.5 mm and a numeric aperture of NA = 0.35 was used to focus the laser on the sample surface The 514.5 nm line of an argon ion laser was used in the excitation source with a backscattering geometry. The Raman spectrum of Brachyphyllumcastilhoi fossil was recorded in the spectral range 250 – 500 cm–1. In the range 330 – 450 cm–1 it is expected to be observed bands associated with S–S vibrations. These are the Raman signatures of pyrite. It is known that Raman spectroscopy gives information about libration and stretching vibrations of S – S units.[2] The bands observed at 342 and 377 were assigned, respectively, as S–S libration and S–S stretching, while a weak band at 428 cm–1 was assigned as a vibration due coupling of libration and stretching of S – S [2,3]. Beyond the three, it was observed peaks -1 at 467, 472 cm which were associated to the Si–O–Si bend of quartz (SiO2) and to the Al–O–Si bend of alumino silicates. Additionally, in other regions of the fossil, Raman spectrum presents vibrations at 222 cm-1 and 218 cm–1, which were associated to Fe – O bend [2]; however, the bands associated with pyrite are dominant. From this analysis we were able to understand that the abundance of sulfur and iron elements in the Cretaceous Period indicates an anoxic environment around the fossilized material during pyritization. We also concluded that pyritization was an additional fossilization mechanism in the Araripe Basin, beyond the most known and well stablished process of calcification, which is

145 Book of Abstracts OP25 dominant in fossils of another geological formation in the same basin, Romualdo Formation. We also studied the Raman spectra of two kinds of woods (Gymnosperms, Araucariaceae) from the Crato Formation: the light wood fossil and dark wood fossil, and their respective matrices. The Raman spectrum of the light wood matrix presented a peak located at ~ 1087 cm–1, which coincides with the most intense peak of calcite material [4]. The Raman spectrum of the dark wood matrix presented peaks at 282 and at 1087 cm–1, which are characteristic of the calcite crystal. In comparison with the Raman spectrum of the light wood matrix we observed two main differences, i.e., the appearance of a band at 282 cm-1 and the high intensity of the band at 1087 cm–1. As a consequence, the quality of the calcite in the dark wood matrix is better than that found in the light wood matrix. The Raman spectrum of the light wood fossil is very complex. We observed bands at 422, 487 cm–1 which were -1 associated with symmetric bending of SO4, n2(SO4); modes located in 612 and 659 cm , which were –1 assigned as asymmetric bending of SO4 ions, n4(SO4), and an intense band observed at 992 cm , which was associated with the symmetric stretching vibration of SO4, n1(SO4). Additionally, a mode observed -1 at about 1126 cm was associated with the asymmetric stretching of the ion SO4, n3(SO4). In general [4] terms the spectrum has resemblance with the spectrum of CaSO4.2H2O ; such a result was confirmed with data from X-ray diffraction measurements. On the other hand, the Raman spectrum of the dark wood fossil is characteristic of materials consisting of amorphous carbon, which present two main peaks. The first band is observed at 1355 cm–1 and is known as band of disorder (D band), while the second peak, centered at 1600 cm–1, is assigned as G (graphitic) band, being related to double bond C = C in materials with such kind of connection. So, we can conclude the two kinds of wood fossils have different constitutions: while the sample of light wood fossil is constituted predominantly by CaSO4.2H2O, the dark wood fossil is constituted mainly by amorphous carbon. From this study we suggest that the origin of the dark wood fossil is a natural fire, occurred in a dry period, while the origin for the light wood fossil is an environment of high salinity and high rates of evaporation.

Acknowledgements This work has been financially supported by CAPES and CNPq.

References [1] P. T. C. Freire, B. T. O. Abagaro, F. E. Sousa Filho, J. H. Silva, A. A. F. Saraiva, D. D. S Brito, B. C. Viana, Pyritization of Fossils from the Langerstätte Araripe Basin, Northeast Brazil, from the Cretaceous Period. in Pyrite: Synthesis, Characterization and Uses. 1ed., Nova Science Publishers: Hauppauge, 2013, p. 123. [2] A. K. Kleppe, A. P. Jephcoat, Mineral. Mag. 2004, 68, 433. [3] H. Vogt, T. Chattopadhyay, H. J. Stolz, J. Phys. Chem. Solids. 1983, 44, 869. [4] M. Bouchard, D. C. Smith, in: H. G. M. Edwards, J. M. Chalmers (eds), RamanSpectroscopy in Archaeology and Art History. The Royal Society of Chemistry: Cambridge, 2005, p. 429.

RAA 2013 146 OP26

Raman spectroscopic analyses of ~75 000 year old stone tools from Middle Stone Age deposits in Sibudu Cave, KZN, South Africa

Linda C. Prinsloo,1* Lyn Wadley, 2 Marlize Lombard3

1 Physics department, University of Pretoria, Hatfield, South Africa, 27 12 420 2458, [email protected] 2 Institute for Human Evolution and the School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand 3 Department of Anthropology and Development Studies, University of Johannesburg, Auckland Park Campus, Johannesburg 2006, South Africa

Sibudu is an extremely important Middle Stone Age rock shelter located on the Tongati River near the KwaZulu-Natal coast of South Africa. It has a large collection of Middle Stone Age deposits that are well preserved and have been accurately dated using OSL (optically stimulated luminescence), giving an occupation span of 77 000 to 38 000 years ago. Direct evidence was found for the use of ochre in the hafting technology of tools from the shelter and replication studies of adhesives that may have been used for hafting the tools show that ochre is indeed useful as loading agent for adhesives.[1,2] Optical microscopic investigations of the stone tools showed that the distribution patterns of ochre and resinous material coincide with the blunted side of the tools, usually associated with hafting, suggesting that the compound mixture was used to glue the tools to their hafts (see Figure 1).

Figure 1. An example of a stone tool where the darker coloured hafting side can clearly be distinguished from the working edge (left). Raman spectra recorded on stone tools from Middle Stone Age deposits in Sibudu Cave, KZN, South Africa (right).

Raman spectra were recorded on both sides of various stone tools from the site with an Alpha WiTec Raman instrument using a 514.6 nm laser as excitation source. Spectra were recorded on both the hafted and working (sharp) sides of each stone tool. An example of the results is presented in Figure 1 where the strongest peak (463 cm-1) in spectrum (a) belongs to a-quartz (found on both the working and hafting sides). Other phases identified through their Raman spectra are hematite (spectrum c, 216, 275 cm-1) recorded on the hafting side, bone (spectrum f, 962 cm-1) on the working side and the interface between sides, calcium carbonate (spectrum g, 1087 cm-1) is randomly distributed and carbonaceous material (spectra d and e, 1350, 1580 cm-1) primarily on the hafting sides. In some spectra more than one phase can be identified.

147 Book of Abstracts OP26

The presence of a-quartz originates from the stone matrix of the tool. The hematite spectra are in line with the microscopic evidence for the use of ochre in the hafting technology and they resemble spectra recorded from ochre from the Wonderwerk Cave in South Africa.[3] The detection of bone on the working edge of the tool suggests that it was used on animals and the presence of residues at the interface between hafting and working edge is due to the accumulation of material where the original hafting configuration terminated on the stone surface. The calcium carbonate is probably from ash, which is abundant in combustion features at the site. The spectra of carbonaceous material range from highly graphitic to amorphous (spectra d and e). It has been shown that fruit and nuts buried underneath hearths in anoxic conditions become carbonized to different extents depending on the distance from the fire, and the carbon is therefore most likely due to the original plant gum that has undergone the same post-burial changes as the fruit and nuts.[4] This study validated the work that has so far been done using microscopy and highlights the usefulness of Raman spectroscopy in the study of Middle Age Stone tools and opens up a whole new avenue of experimentation.

Acknowledgements The authors wish to thank the NRF, and the Universities of Pretoria, the Witwatersrand and Johannesburg for their financial support. Results and inferences are, however, those of the authors and not the funding or supporting institutions.

References [1] L. Wadley, J. Hum Evol. 2005, 49(5), 587–601. [2] M. Lombard, J. Hum Evol. 2007, 53(4), 406–419. [3] L. C. Prinsloo, A. Tournié, P. Colomban, C. Paris, S. T. Bassett, J. Archaeol Sci. 2003, 40(7), 2981– 2990 [4] C. Sievers, L. Wadley, J. Archaeol Sci. 2008, 35, 2909–2917.

RAA 2013 148 OP27

Raman spectroscopy in archaeometry: multi-method approaches and in situ investigations: advantages and drawbacks

Peter Vandenabeele,1* Luc Moens2

1 Research group in Archaeometry, Department of Archaeology, Ghent University, Ghent, Belgium, [email protected] 2 Raman Spectroscopy Research Group, Department of Analytical Chemistry, Ghent University, Ghent, Belgium

In archaeometry, it is the aim to maximise the amount of information that is obtained from an object while minimising the risk on damage to the art object. This criterion can be met by using several complementary analytical techniques, especially when these techniques are compatible to perform in situ investigations. The current research paper focusses on these two important aspects of current archaeometrical projects: on the one hand the use of multi-analytical approches (where Raman spectroscopy is combined with other non-destructive analytical techniques) and on the other hand the state-of-the art of mobile analytical approaches. Raman spectroscopy has grown to be one of the preferred techniques when investigating art objects. Indeed, the technique is well-appreciated for, amongst others, its non-destructive character, the possibility to obtain molecular information at a micrometer-level and its speed of analysis. Moreover, this is a very versatile analytical approach, that allows the archaeometrist to obtain analytical information from a very broad range of materials (e. g. pigments, glass, ceramics, minerals, glazes, corrosion products, gemstones, biomaterials, etc.) of different periods. However, where we highly esteem the possibilities of the approach, sometimes it can be useful to complement the approach with other analytical techniques, so that more complete information is obtained. When using multiple analytical techniques, this has some implications towards the analytical procedures concerning planning, documenting and the workflow of the approach. One of the main advantages of Raman spectrosocpy, is that it can be used to investigate an artwork directly – thus reducing the need for sampling. Today, several Raman instruments are available for in situ investigations. However, all approaches have their advantages and drawbacks. In this presentation, we will focus on the specific needs in archaeometry, to have a versatile, yet mobile Raman spectroscopic approach. This will be illustrated with a broad range of applications from daily lab practice: the analysis of pigments, manuscripts, paintings and ceramics.

Acknowledgements The authors wish to acknowledge the MEMORI project for their financial support and for the interesting discussions with the colleagues. The MEMORI, ‘Measurement, Effect Assessment and Mitigation of Pollutant Impact on Movable Cultural Assets. Innovative Research for Market Transfer‘, project is supported through the 7th Framework Programme of the European Commission (http://www. memori‑project.eu/memori.html).

149 Book of Abstracts OP28

Spectroscopic Analysis of Chinese Porcelain Excavated in Clairefontaine (Belgium): Pigment Identification and Dating

Jolien Van Pevenage,1* Debbie Lauwers,1 Davy Herremans,2 Eddy Verhaeven,3 Bart Vekemans,4 Wim De Clercq,2 Laszlo Vincze,4 Luc Moens,1 Peter Vandenabeele2

1 Raman Spectroscopy Research Group, Department of Analytical Chemistry, Ghent University, Ghent, Belgium, +32 9 2644719, [email protected] 2 Department of Archaeology, Ghent University, Ghent, Belgium 3 Department of Conservation and Restauration, Artesis Hogeschool Antwerpen, Antwerp, Belgium 4 Department of Analytical Chemistry, Ghent University, Ghent, Belgium

The porcelain objects, investigated in this project, were found in a latrine of the Cistercian abbey of Clairefontaine (Belgium). From archaeological point of view, based on the shape and the style, the porcelain objects are thought to be Chinese, dating from the first half of the 18th century. However most of these chronologies have kept up for years and are rarely supported by absolute dating or determination of the origin. By doing spectroscopic research on these samples, more certainty about the production date and origin of these samples can be retrieved. According to the macroscopical analysis of the decoration patterns, the Clairefontaine porcelain could be divided in two main groups. Group A consists of porcelain characterized by an abundantly blue- and-white decoration. A variety of designs appear such as crabs, flowers and Chinese landscapes. A limited part of the vessels was painted brown on the surface. Both designs and colour patterns suggests a production under emperor Kangxi (1661-1722) [1]. The second group comprises porcelain with more colourful decoration. Both decoration and colour range suggests a production under emperor Qianlong (1735-1795). A variety of designs appear including Chinese landscapes, rural sceneries with birds, flowers and rodents, and more abstract floral decoration. Typical for Qianlong porcelain is the wide range of pigments used for the application of these desings [1–2]. The colour range on the Clairefontaine vessels consists of gold, red and green. All the objects of group B have a brown decorated exterior. In this project, both Raman spectroscopy and X-Ray Fluorescence (XRF) spectroscopy are used for the characterization and identification of the samples. By using these two complementary techniques we gather molecular (Raman) and elemental (XRF) information about the different porcelain objects. All groups and subgroups were sampled. A set of 36 samples covering the variety of pigments was separated for further analysis. Before Raman and XRF analysis, samples are cut, embedded and polished, in order to be able to measure on the transversal side of the samples. The glaze layers of the porcelain objects were analysed. The following results are obtained: the samples of group A were probably produced under emperor Kangxi (1661–1722), based on the presence of cobalt

blue (CoAl2O4). The identification of hematite (α-Fe2O3) and malachite (Cu2CO3(OH)2) ascertains without doubt that the objects of groups B1, B2 and B3 were produced during the Qing period (1644–1922). In

the glaze layers of the samples of group B1, also an opaque lead tin yellow type II (PbSn1-xSixO3, where x ~ ¼), and an opaque lead acetate were identified, which indicates that these samples date from the emperor Qianlong (1735–1795), more precisely. These former two pigments belong to the colour pallet of famille rose porcelain, which was very famous during this period. At last, the golden colour was identified as a mixture of gold and lead. It can be concluded that Raman and XRF spectroscopy form a perfect match for the analysis of Chinese porcelain as it are complementary and non-invasive techniques, which allow identification of pigments,

RAA 2013 150 OP28 used to colour the glaze layers, with the result that retrieving the production date of porcelain objects becomes possible.

Acknowledgements Special acknowledgments go to Prof. dr. J. De Meulemeester (†), who directed archaeological fieldwork at Clairefontaine, and to the Walloon Governement, ©SPW-DPat, who financed this project. Post- excavation research is carried out within the framework of the PhD-project (FNR Luxembourg– BFR06-80): “The material culture of Clairefontaine abbey”.

References [1] J. Wu, P. L. Leung, M. J.Stokes, M. Li, X-Ray Spectrometry. 2000, 29, 239–244. [2] J. Miao, B. Yang, D. Mu, Archaeometry. 2010, 52, 146–155.

151 Book of Abstracts OP29

Characterization of ancient ceramic using micro-Raman spectroscopy: the cases of Motya (Italy) and Khirbetal-Batrawy (Jordan)

Laura Medeghini,1* Pier Paolo Lottici,2 Caterina De Vito,3 Silvano Mignardi,3 Danilo Bersani,2 Mariangela Turetta,2 Jennifer Costantini,2 Elena Bacchini,2 Maura Sala,4 Lorenzo Nigro4

1 PhD in Applied Sciences for the Protection of the Environment and of Cultural Heritage, Department of Earth Sciences, Sapienza University, Rome, Italy, +39 0649914155 [email protected] 2 Department of Physics and Earth Sciences, University of Parma, Parma, Italy. 3 Department of Earth Sciences, Sapienza University, Rome, Italy. 4 Department of Sciences of Antiquities, Sapienza University, Rome, Italy

In the last years, the number of scientific contributions in which Raman spectroscopy is the key technique to analyze archaeological objects is continuously increasing. In particular, the application of this non-destructive technique in the characterization of ancient ceramic has received a major boost. The spectroscopic information obtained by Raman analysis allows for the mineralogical characterization of pottery, answering to the main questions of archaeologists about the nature and provenance of raw materials for ceramic production, as well as exploring the technological aspects of the firing conditions and post-burial processes.[1-8] We report in this study two different types of ceramics in terms of technological fingerprints and preparation of the raw materials with the aim to show how micro-Raman spectroscopy can answer the above questions. Micro-Raman spectroscopy has been applied on ancient ceramics from two archaeological sites of the Mediterranean area and Near East. The first case is Punic “Black-Gloss Ware” from the Phoenician- Punic site of Motya (Sicily, Italy), dating back from the end of 6th to the early 4th century B.C. These ceramics are the result of a high technological background due to imitation of the most famous Attic production, diffused in all Mediterranean world. As a second case study, pottery samples with lower technological background have been selected from the archaeological site of Khirbet al-Batrawy (Jordan), dating back in the III millennium B.C. The use of micro-Raman spectroscopy allowed us to characterize the mineralogical composition of the vessels fragments in order to define the pottery composition and the firing conditions, the nature of the black gloss of Motyan ceramics and of the superficial decorations of Jordan ceramic. Moreover, Raman results combined with those obtained by optical microscopy, X-ray diffraction and SEM-EDAX analysis helped in the reconstruction of the raw material provenance. In the case of Motya samples, the internal body is composed by quartz, feldspars, pyroxenes, micas, gehlenite, magnetite, and haematite. In addition to previous minerals hercynite also occurs in the black gloss. Chemical data showed that the main body and the black gloss contained the same major elements: Si, Al, Fe, Ca, K, Mg, Ti, and Na. However, a Fe-enrichment in the black gloss has been

observed. The ceramic samples were exposed to similar firing temperatures and fO2 as suggested by mineral assemblage: estimated T is the range 1000-1100 °C at oxidizing-reducing-oxidizing conditions. The potential sources of raw materials used for ceramic production are difficult to infer as the starting material was selected and purified; however, the presence of a kiln in Motya proves a local production. [9]

RAA 2013 152 OP29

In the Khirbet al-Batrawy pottery, calcite and quartz are the main components. Hematite, magnetite and carbon are frequently found in all samples. K-feldspar, plagioclase, apatite, gypsum, titanium dioxide (anatase and rutile), pyroxenes, bassanite, barite, zircon, and olivine have been detected in minor amounts and only in few samples. Detailed micro-Raman analysis has been carried out on the superficial decorations of fragments. Raman spectra revealed the occurrence of hematite in red decorations, whereas amorphous carbon has been found in the black ones. The co-presence of calcite, diopside, anatase, and rutile, mineral phases having different thermal fields of stability, allows to hypothesize a firing temperature range of Khirbet al-Batrawy ceramic between 850 and 900 °C. The diffuse occurrence of hematite probably indicates an oxidizing atmosphere during firing, whereas the presence of magnetite could indicate an incomplete transformation from magnetite to hematite.[10] The exhaustive information about mineralogical composition in potteries obtained allows to define the technological process of production, underlining the key role of micro Raman spectroscopy in the study of archaeological ceramic.

Figure 1.Views of the two archaeological sites: Motya a.) and Khirbetal-Batrawy b.).

References [1] G. Barone, S. Ioppolo, D. Majolino, P. Migliardo, G. Tigano, J. Cult. Herit. 2002, 3, 145. [2] C. M. Belfiore, M. di Bella, M. Triscari, M. Viccaro, Mater. charact. 2010, 62, 440. [3] G. Cultrone, C. Rodriguez-Navarro, E. Sebastian, O. Cazalla, M. J. De La Torre, Eur. J. Mineral. 2001, 13, 621. [4] A. Iordanidis, J. Garcia-Guinea, G. Karamitrou-Mentessidi, Mater. Charact. 2009, 60, 292. [5] L. Maritan, Eur. J. Mineral. 2004, 16, 297. [6] C. Rathossi, P. Tsolis-Katagas, C. Katagas, ApplClaySci, 2004, 24, 313. [7] C. Tschegg, J. Archeol. Sci. 2009, 36, 2155. [8] G. Velraj, K. Janaki, A. M. Musthafa, R. Palanivel, Appl. ClaySci. 2009, 43, 303. [9] G. Falsone, Struttura e origineorientaledeiforni del vasaio di Mozia, Fondazione G. Whitaker: Palermo, 1981, p. 89. [10] C. Lofrumento, A. Zoppi, E. M. Castellucci, J. RamanSpectrosc. 2004, 35, 650.

153 Book of Abstracts OP30

Hispano-Moresque architectural tiles from the Monastery of Santa Clara-a-Velha, in Coimbra, Portugal: a µ-Raman study

Susana Coentro,1,2 Rui M. C. Silva,2 Vânia S. F. Muralha1

1 VICARTE – Research Unit “Glass and Ceramics for the Arts”, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Caparica, Portugal 2 Instituto Tecnológico e Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Sacavém,Portugal

In the last decades of the 20th century, several archaeological campaigns in the Monastery of Santa Clara-a-Velha, in Coimbra, brought to light an impressive collection of Hispano-Moresque glazed tiles. Among this collection, dated from the 15th and 16th centuries, we find complex techniques such as cuerda-seca, arista and relief, but also simpler techniques as flat monochromatic tiles. There were also excavated unglazed arista pieces and a large number of trivets, which casted doubts on the subject of provenance, usually attributed to Seville, in Spain. This study is focused on the chemical and morphological characterisation of the tile collection from the Monastery of Santa Clara-a-Velha, with the intent of understanding its production technology and gather information to later compare with other Hispano-Moresque tile collections in Portugal and Spain. In this context, both the ceramic bodies and glazes of the tiles were analysed by μ-Raman spectroscopy.

A typical Raman spectrum of a glass or glaze material shows two main broad bands, corresponding to the Si-O bending vibration (about 500 cm-1) and the Si-O stretching vibration (about 1000 cm- 1). The shape, intensity and mathematical fitting of these bands are characteristic of a certain glass composition, and can infer on processing temperatures of manufacture, substitution patterns and discriminating between different groups. In this study, the band at 1000 cm-1 is always stronger, as it is characteristic for lead glazes. Differences in intensity and shape of the bands are detected for different- coloured glazes and it will be discussed alongside the glazes quantitative data.

Another important element that m-Raman can provide is the characterization of the glaze-ceramic interface (where chemical reactions occur during firing and new crystalline phases are formed), an important aspect in glazed ceramics to understand the production technology. These crystals depend on the chemical composition of the glaze and the ceramic paste, and also on the firing conditions. Glazes

are very homogeneous and only cassiterite (SnO2), was identified very well distributed through all the glaze depth. Other crystalline phases were only identified in interface and seem to be the outcome of the reaction between the lead glaze and the calcium-rich ceramic body. Some phases identified

include wollastonite (CaSiO3), andradite (Ca3Fe2Si3O12) malayite (CaSnOSiO4) crystals, and bustamite

(CaMnSi2O6). The results will be discussed according to the glaze colour composition.

RAA 2013 154 OP31

The blue colour of glass and glazes in Swabian contexts (South of Italy): an open question

Maria Cristina Caggiani,1,3 Pasquale Acquafredda,2 Philippe Colomban,3 Annarosa Mangone1*

1 Chemistry Department, Bari University “Aldo Moro”, Bari, Italy, +39805442117, [email protected], +39805442022, [email protected] 2 Earth Science and Geo-Environmental Department, Bari University “Aldo Moro”, Bari, Italy, +39805442613, [email protected] 3 Ladir umr 7075, CNRS, Université Pierre et Marie Curie, c49, Paris France, +33-144272785, [email protected]

The most known and studied medieval enamelling productions occurred in the Islamic culture with the gilded and enamelled works produced between the 13th and 14th centuries. In literature, some earlier groups of objects attesting the existence of an anterior manufacturing, also of different provenances, are documented, such as the Roman Lübsow beaker (first half of nd2 cent. AD)[1] and the Begram treasure (1 st-2nd cent. AD). The recent discovery of enamelled glass objects (Figure 1a) in Frederick II Melfi castle (South of Italy), with a dating prior to the end of the 13th century, brings into question the exchanges of knowledge, technological procedures, raw materials and artefacts. In this work, importance is given to the blue colour because in our specific case it can provide clues about technological choices and economic circumstances. Recently, archaeometric studies are strongly contributing to demonstrate that a material considered for long time extremely precious, of difficult availability and expensive like lapis lazuli was actually used more often and in more differentiated geographical contexts than thought. One case is that of pottery glazes and glass fragments where lapis lazuli was found coming from different contexts connected to Frederick II influence: the abandoned Medieval village of Castel Fiorentino, the fortress in Lucera, the only surviving mosaic tile of the original mosaic decoration of Castel del Monte,[2] and the medieval sea port of Siponto.[3] Also the Raman analyses conducted on the blue enamels of Melfi samples showed the presence of the - - radical anions chromophores S2 S3 , typical of lazurite mineral, principal constituent of lapis lazuli. In this case, though, due to the presence, in the same area of the archaeological findings, of two rocks that contain haüyne, a mineral belonging to sodalite group like lazurite: Phonolite of Toppo San Paolo (Figure 1b’) and Haüynophire of Melfi, the latter located exactly at the foot of the town, a question arose on the real nature of the enamels raw materials, in the lack of local artisans manuscripts of receipts and procedures. In order to understand if the chromophore-bearing mineral in the artefacts could be other than lazurite, the two volcanic rocks and some archaeological samples with blue enamels were subjected to a study through Optical Microscopy (OM), Raman micro-spectroscopy and micro X-ray Diffraction (µ-XRD). In the rocks, particular attention was given to the haüyne crystals that can be blue or become blue after heating (Figure 1b’’).[4] Flat-surfaces chunks of the rocks phonolite and haüynophire were heated up to different temperatures (400, 700, 900°C) and after observed through optical microscopy and analysed by micro-Raman spectroscopy at different wavelengths, also by means of areal mappings after each step. Raman analyses were also carried out on single crystals of lazurite and haüyne during heating and cooling in a special temperature controlled chamber up to 900°C in order to follow the crystal evolution during the entire process.

155 Book of Abstracts OP31

The results obtained allowed to understand that a transformation occurs in haüyne mineral starting from about 700°C, after which the Raman spectrum shows an increase in intensity and diffusion in the - - crystal of the S2 S3 signature, the same as lazurite chromophores whose absorbance spectrum was in this work experimentally reconstructed.

Figure 1. a.) one of the samples of gilded and enamelled glass from Melfi; b) optical microscope (OM) micro-photographs of thin sections of fragments of phonolite rock: b.) in the not-heated sample, haüyne crystals are from colourless to black, b.) in the heated one (900°C for 11 days) they appear blue.

The preliminary results obtained on real samples of blue enamels would lead to think to the use of lapis lazuli, but this will be better seen with further studies and experimental archaeology productions of glass including haüyne-bearing rocks.

References [1] S. Greiff, J. Schuster, J. of Cultural Heritage. 2008, 9 (Supplement 1), 27. [2] I. M. Catalano, A. Genga, C. Laganara, R. Laviano, A. Mangone, D. Marano, A. Traini, J. of Archaeological Science. 2007, 34, 503. [3] A. Traini, L. C. Giannossa, R. Laviano, A. Mangone, Le indagini archeometriche dei reperti ceramici, in C. Laganara (Ed.): Siponto. Archeologia di una città abbandonata nel Medioevo. Claudio Grenzi: Foggia, 2011, p. 133. [4] P. Ballirano, Physics and Chemistry of Minerals. 2012, 39(9), 733.

RAA 2013 156 OP32

Spectroscopic characterisation of crusts interstratified with prehistoric paintings preserved in open-air rock art shelters

Antonio Hernanz,1* Juan F. Ruiz-López,1 Juan Manuel Madariaga,2 Egor Gavrilenko,3 Maite Maguregui,2 Silvia Fdez-Ortiz de Vallejuelo,2 Irantzu Martínez,2 Ramiro Alloza- Izquierdo,4 Vicente Baldellou-Martínez,5 Ramón Viñas-Vallverdú,6 Albert Rubio i Mora,7 África Pitarch,2 Anastasia Giakoumaki2

1 Departamento de Ciencias y Técnicas Fisicoquímicas, Facultad de Ciencias, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain, +34 91 398 7377, [email protected] 2 Department of Analytical Chemistry, Faculty of Science and Technology, University of Basque Country, Bilbao, Spain, [email protected] 3 Instituto Gemológico Español, Madrid, Spain, [email protected]. 4 Laboratorio de Análisis e Investigación de Bienes Culturales, Gobierno de Aragón, Zaragoza, Spain, [email protected] 5 Museo de Huesca, Huesca, Spain, [email protected] 6 Ramón Viñas-Vallverdú, Dr., Instituto Català de Paleoecología Humana y Evolució Social (IPHES), Tarragona, Spain, [email protected] 7 Centro Asociado de Cervera, Cervera, Lleida, Spain, [email protected]

One of the main difficulties applying on-site and laboratory m-Raman spectroscopy to study prehistoric paintings from open-air rock shelters is the presence of layers of fluorescent materials interstratified with the pigment.[1] A considerable number of on-site m-Raman analytical campaigns in significant open-air rock art sites from the Iberian Peninsula have undergone this problem. The objective of this work is to characterise the composition and microestratigraphic distribution of these layers, to infer its origin and to present methods to deal with this difficulty. The painting panels of the rock shelters Cova dels Rossegadors (Pobla de Benifassà, Castellón), Cueva de la Vieja and Cueva del Queso (Alpera, Albacete), Los Chaparros (Albalate del Arzobispo, Teruel) and Riquelme (Jumilla, Murcia) in the Iberian Peninsula have been studied. This work collects the results of several archaeological seasons in these sites developed by diverse researchers; hence the large number of co-authors. On-site and laboratory m-Raman spectroscopy have been applied. SEM/EDX and polarized optical microscopy have been used as auxiliary techniques.

Previous on-site EDXRF screening analyses of the walls were very useful to detect elemental signals from pigments that are covered by crusts and remain hidden to the human eye, an advantage of the EDXRF penetration depth. The presence of a supposed pictograph in Cova dels Rossegadors has been confirmed this way. Different layers of accretions have been discovered in this site studying thin cross sections, Figure 1. A thick crust made difficult the on-site ‑m Raman study of the Cueva de la Vieja pigments. The repeated spraying of water to exhibit clearly the pictographs, an unfortunate frequent practice, has caused this crust. A deplorable example of anthropic deterioration. The walls of Los Chaparros and Riquelme rock shelters appear covered by an orange crust that produces strong fluorescence radiation even exciting at 785 nm. Wind-blown dust and surface water runoff could have contributed to form some of these crusts. Clay minerals, clayey loams, marls, calcite and dolomite are the most frequent components found in the crusts. In spite of these difficulties, a careful selection of the operating conditions of the spectrometers made possible in some cases to record acceptable Raman spectra. On the other side, the finding of interstratified layers of calcium oxalate (whewellite

157 Book of Abstracts OP32 and weddellite) with the pigment is very helpful to achieve the AMS 14C dating of the paintings, a fundamental objective for the archaeologists.[2-4] These methodology can be applied to other shelters, where men have left paintings preserved during thousands of years.

Figure 1. Microphotograph with polarised light of a thin section of the crusts interstratified with prehistoric paintings in the Cova dels Rossegadors rock shelter, Pobla de Benifassà, Castellón, Spain.

Acknowledgements We gratefully acknowledge Dr. S. Martin (Dept. Física Matemática y Fluidos, UNED) for their help in recording SEM/EDX data. This work has been financially supported by project I+D+i CTQ2009-12489 from Ministerio de Ciencia e Innovación and funds from Dept. Analytical Chemistry (EHU, Bilbao, Spain).

References [1] A. Hernanz, J. F. Ruiz-López, J. M. Gavira-Vallejo, S. Martin, E. Gavrilenko, J. of Raman Spectrosc. 2010, 41, 1104–1109. [2] A. Hernanz, J. M. Gavira-Vallejo, J. F. Ruiz-López, J. of Optoelectronics and Advanced Materials. 2007, 9, 512–521. [3] J. F. Ruiz, M. M. Mas, A. Hernanz, M. W. Rowe, K. L. Steelman, J. M. Gavira, International Newsletter on Rock Art. 2006, 46, 1–5. [4] J. F. Ruiz-López, A. Hernanz, R. A. Armitage, M. W. Rowe, R. Viñas, J. M. Gavira-Vallejo, A. Rubio, J. of Archaeologial Science. 2012, 39, 2655–2667.

RAA 2013 158 P40

Micro-Raman on Roman glass mosaic tesserae

Claudia Invernizzi,1,2* Elena Basso,1,3 Marco Malagodi,1,4 Mauro Francesco La Russa,5 Danilo Bersani,2 Pier Paolo Lottici2

1 Laboratorio Arvedi-CISRiC, Università di Pavia, Italy, [email protected] 2 Dipartimento di Fisica e Scienze della Terra, Università di Parma, Italy, [email protected], [email protected] 3 Dipartimento di Scienze della Terra e dell’Ambiente, Università di Pavia, Italy, [email protected] 4 Dipartimento di Chimica, Università di Pavia, Italy, [email protected] 5 Dipartimento di Scienze della Terra, Università della Calabria, Arcavacata di Rende, Cosenza, Italy, [email protected]

The results of a Micro-Raman spectroscopy investigation performed on twenty-one Roman glass mosaic tesserae (II century A.D.), from the “Villa dei Quintili” excavation in Rome, are reported. The set of tesserae was retrieved in the thermal baths and covers the majority of the colour palette of that time. The aim was to identify the raw materials, the colouring agents and the opacifiers as well as the production technology used during the Roman Imperial Age. FESEM-EDS and LA-ICP-MS were also employed for a detailed spectroscopic characterization of both the glass matrix and the crystalline inclusions. The tesserae are made by soda-lime glass produced with natron as flux. For some red samples higher

levels of MgO e K2O suggest the use of plant-ashes as a source of alkali. Sn-Pb antimonates (yellow), Ca-antimonates (white), a mixture of Cu2+ ions and Sn-Pb antimonates (green), a mixture of Ca-antimonates and Cu2+ or Co2+ ions (blue and blue-green) are the colouring and 0 opacifying agents used. Cu metal nanoparticles and Cu2O nanocrystals are found in the red and orange lead-containing tesserae. The results confirm the high technological level of Imperial Age glassmakers and emphasize the importance of complementary micro-analytical (SEM-EDS and LA-ICP-MS) and spectroscopic (µ-Raman) techniques.

Figure 1. Raman spectra of calcium antimonates:

a.) CaSb2O6, b.) Ca2Sb2O7

159 Book of Abstracts P41

Raman and IR Spectroscopic Study of Vitreous Artefacts from the Mycenaean to Roman Period: Glassy Matrix & Crystalline Pigments

Doris Möncke,1* Eleni Palamara,2 Dimitri Palles,3 Efstratios I. Kamitsos,3 Nikos Zacharias,2 Lothar Wondraczek1

1 Otto-Schott-Institut, Friedrich-Schiller-Universität, Jena, Germany, +49-3641-948505, [email protected], [email protected]. 2 Laboratory of Archaeometry, Department of History, Archaeology and Cultural Resources Management, University of Peloponnese, Kalamata, Greece, [email protected], [email protected] 3 Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens, Greece, [email protected], [email protected]

Coloured glasses and glass ceramics such as glazes, enamels or mosaic tesserae were studied in regard to the glass structure and for eventual present crystalline particles. The samples come from the Peloponnese and belong to the Mycenaean, Classic Hellenic and Roman Period. Attic black glazed fragments from the Classical period and glazed pottery from Corinth of the ‘Byzantine period were also included in this study. Quantitative analysis by SEM/EDX is available for most samples while some had also been studied by X-ray diffraction for the identification of crystalline minerals, or by optical spectroscopy for the absorption bands of dissolved transition metal ions used as colourants. Reflectance infrared spectroscopy (IR) and the FT-IR microscope were used for structural studies of the glass samples and the vitreous substrate of glazes, enamels or tesserae. Micro-Raman analysis complimented these studies and helped additionally via Raman fingerprint spectral identification in the characterization of various opacifiers and colouring pigments. Thermal properties (transition, melting and crystallization temperature) of the glass substrate and the identified pigments can be used to deduce the outer limits of possible process windows during preparation of these vitreous artefacts. Such information will help in distinguishing pigments which were added at some point to the melt but did not fully dissolve, from crystalline particles which only precipitated upon cooling of the melt, or from particles which might even need an additional annealing step in which the finished glass sample was tempered in a second production step for a certain time. The identified pigments will also be compared with naturally occurring pigments in order to distinguish these from artificially prepared crystalline particles. The variation of different pigments and different combinations of opacifiers and pigments in different regions and over time will be studied in various vitreous materials.

Figure 1. Classic Hellenic vessel fragment of a cobalt blue coloured glass matrix and decorative lining. Raman spectroscopy identified the yellow pigment

Naples Yellow (Pb2Sb2O7) and in both, the white and

yellow lines also the white opacifier CaSb2O6.

RAA 2013 160 Acknowledgements DM wants to thank the Fritz Thyssen Foundation for financial support.

References [1] D D. Möncke, D. Palles, N. Zacharias, M. Kaparou, E. I. Kamitsos, L. Wondraczek, Phys. Chem. Glasses: Eur. J. Glass Sci. Technol. 2013, B54, 52–59. [2] M. Papageorgiou, N. Zacharias, K. G. Beltsios, Analytical and Typological Investigation of Late Roman mosaic tesserae from Ancient Messene, Greece, Proceedings of the ΑΙHV 18, D. Ignatiadou, A. Antonaras (eds.), Thessaloniki, 2012, 241–248.

161 Book of Abstracts P42

The detection of Copper Resinate pigment in works of art: contribution from Raman spectroscopy

Irene Aliatis,1* Claudia Conti,2 Geneviève Massonnet,3 Cyril Muehlethaler,3 Tommaso Poli,4 Matteo Positano,5 Elena Possenti,2 Jana Striova6

1 University of Parma, Dep. DIFEST, Parma , Italy, +390521905206, [email protected] 2 ICVBC-CNR, Milan, Italy 3 University of Lausanne, School of Forensic Science, Institut de Police Scientifique, Lausanne Dorigny, Switzerland 4 University of Turin, Dep. Chemistry I.F.M., Turin, Italy 5 Emmebi diagnostica artistica s.r.l., Rome, Italy 6 CNR-INO and LENS, University of Florence, Sesto Fiorentino, Italy

Copper resinate is a green pigment widely used in the 16th century by Italian painters, as many surveys on Caravaggio[1] and on Flemish paintings proved.[2] This pigment consists of a transparent green glaze and its colour is obtained by copper salts of resin acids. The composition of this compound is controversial and a great variety of recipes exists. Verdigris is always the principal ingredient giving the glaze its green colour and old recipes suggest the preparation of copper resinate by mixing verdigris with terpenic resins, as Venice turpentine (conifer resins).[2] Given the complexity of the nature of copper resinate, its identification is matter of debate. In several cases, the detection of this pigment has been based only on the observation of its morphology;[1] the identification of its characteristic FTIR pattern[3] is generally quite uncertain due to the copresence of the binder and other pigments. To date, the best analytical technique for the detection of copper resinate is gas chromatography coupled with mass spectrometry (GC-MS). This method allows identifying the terpenic compounds and their characteristic oxidation products,[4] but it is a sample destroying and relatively time consuming technique. At the present time, there are a few Raman studies of copper resinate published in literature; generally fluorescence obscures the Raman scattering[5] or weak bands make its characterization difficult.[6] Raman analyses carried out by the authors during the last years on several paintings, included “Madonna dei Pellegrini” by Caravaggio (Figure 1), highlighted the need of an extensive study of the Raman vibrational features of copper resinates. Therefore, the aim of this work is to study copper resinates available on the market nowadays and thus to verify the possiblity of Raman identification of this pigment in paintings. Commercial copper resinate pigments have been also characterized by elemental and microscopical analyses (portable XRF and SEM-EDS) as well as by FTIR spectroscopy. 488, 514, 532, 633, 785 and 830 nm laser lines of different Raman spectrometers have been used to analyze raw samples and painted layers prepared spreading copper resinate with linseed oil. Collected spectra have been compared to the ones of verdigris in order to identify the Raman lines specific of the two green pigments. The comparison of the Raman spectra recorded by different sources highlighted the possibility to distinguish copper resinate from the other green pigments; Raman spectra will be presented, discussed and compared with FTIR spectra.

References [1] P. D. Weil, Rev. Bras. Arqueometria, Restauraçao e Conservaçao. 2007, 1, 106. [2] H. Kühn, Artists’ Pigments. A Handbook of Their History and Characteristics, vol. 2, Oxford University Press: Oxford, 1997, p. 131.

RAA 2013 162 P42

[3] H. Kühn, Stud. Conserv. 1970, 15, 12. [4] M. P. Colombini, G. Lanterna, A. Mairani, M. Matteini, F. Modugno, M. Rizzi, Ann. Chim-Rome. 2001, 91, 749. [5] S. Daniilia, D. Bikiaris, L. Burgio, P. Gavala, R. J. H. Clark, Y. Chryssoulakis, J. Raman Spectrosc. 2002, 33, 807. [6] M. L. Franquelo, A. Duran, L. K. Herrera, M. C. Jimenez de Haro, J.L. Perez-Rodriguez, J. Mol Struct. 2009, 404, 924–926.

Figure 1. a.) Detail of “Madonna dei Pellegrini” by Caravaggio, 1604- 1606, Basilica di Sant’Agostino, Rome. The black square indicates the sampling point. b.) Cross section of the sample; the white segment indicates the investigated layer, likely composed of copper resinate.

163 Book of Abstracts P43

Micro-Raman and internal micro-stratigraphic analysis of the painting materials in the rock-hewn church of the Forty Martyrs in Şahinefendi, Cappadocia (Turkey)

Claudia Pelosi,1* Giorgia Agresti,1 Maria Andaloro,1 Pietro Baraldi,2 Paola Pogliani,1 Ulderico Santamaria1

1 Department of Cultural Heritage Sciences, University of Tuscia, Viterbo, Italy, +390761357684, [email protected] 2 Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy, +390592055087, [email protected]

The aim of this work is to investigate the pigments, the mortars and the degradation products in the wall paintings of the Forty Martyrs church, a medieval rock-hewn settlement in Cappadocia, the central region of Turkey (UNESCO Heritage). This work is part of a wider research project called “Rock paintings in Cappadocia. For a project of knowledge, conservation and enhancement of the church of the Forty Martyrs at Şahinefendi and its territory”. The study of the extraordinary pictorial complex of Cappadocia is a prerequisite knowledge necessary to carry out its conservation, restoration and valorization. It is worth stressing that the rock hewn wall paintings are the result and the peculiar expression of Cappadocia’s environmental scenic context where the permanent union between a stunning landscape and the painted churches constitutes the very identity of this area. The Forty Martyrs church is characterized by wall paintings applied on pink-white mortars sometimes containing vegetable fibers. The plaster was generally spread by means of large horizontal bands relating to the scaffolding lifts. A conservation work was performed in order to unveil the wall paintings covered by a thick sooty layer due to the fires lit in the past. The cleaning intervention revealed a wide figurative cycle which develops throughout the two naves of the church (see figure below).[1] The various aspects of the research were supported by scientific analyses carried out according to a methodological path tested during the several years of surveys in Turkey.[2] The preliminary in situ investigations were performed by a portable video microscope, Dino Lite AM 413 in order to study in detail the painted surfaces and to choose the best sampling points for the laboratory analysis.[3] The micro samples, collected during the 2006-2011 campaigns in Cappadocia, were analysed by different and complementary laboratory techniques in order to obtain as much information as possible about the materials and the technique. The sample cross sections were observed and photographed using a Zeiss Axioskop polarising microscope equipped with a Zeiss AxioCam digital camera. Cross sections were also studied under UV lighting, using a Mercury Vapour lamp directly connected to the microscope in order to observe the materials’ fluorescence, and by Raman microscopy. The micro-Raman spectrometer used in this case to characterize the pigments and the possible degradation materials, was a Labram Model from the Jobin Yvon-Horiba with a spatial resolution of 1 µm and with quick detection ability as a result of the CCD detector 1024x256 pixels cooled to -70 °C by the Peltier effect. The spectral resolution was 5 cm-1. The exciting wavelength was the 632.8 nm red line of a He-Ne laser. Infrared spectroscopy was also applied by using a Nicolet Avatar 360 Fourier transform spectrometer. For each sample 128 scans were recorded in the 4000 to 400 cm-1 spectral range in diffuse reflection modality (DRIFT) with a resolution of 4 cm-1. Spectral data were collected with OMNIC 8.0 software.

RAA 2013 164 P43

The Forty Martyrs church at Şahinefendi is characterized by the presence of at least four pictorial phases put in evidence during the conservation work. The micro stratigraphic analysis of the samples taken from the Forty Martyrs layer showed a white, sometimes pinkish, plaster: micro-Raman analysis, performed both on the cross-sections and on the powders, allowed to detect the presence of calcite, gypsum, anhydrite and calcium oxalate. Gypsum is present in all the mortar with a greater concentration in the area under the painting layers: probably it was used as a setting layer. Apart the traditional pigments of the medieval wall paintings, micro-Raman analysis revealed the presence also of organic dye and lead based compound sometimes characterized by degradation phenomena. Between the yellow pigments, jarosite was also found, an iron silicate rarely used as painting pigment. The scientific analysis of the Forty Martyrs church supported the art historians and restorers work to define the chronology of the painting layers and to study the materials and techniques. The internal micro stratigraphic analysis and the spectroscopic techniques allowed to found that the mortar in the Forty Martyrs’ layer was made of lime probably with the addition of organic materials and the painted layers were applied over a thin setting made of gypsum by a secco or lime technique. The main pigments are natural earths and ochres, lead based compounds, ultramarine blue and indigo. Some deterioration phenomena were also observed, probably due to the fires lit in the church during the past years. The conservative intervention restored the legibility of the pictorial scenes also allowing a valorisation of the church and of its entire territory.

Figure 1. The Forty Martyrs’ scene at Şahinefendi before and after the cleaning intervention by University of Viterbo

Acknowledgements The survey in Cappadocia is part of a wider project called For a data bank of wall paintings and mosaics of Asia Minor (4th–15th centuries): images, materials, techniques of execution, directed by Prof. Dr. Maria Andaloro. The project couldn’t have been carried out without the kind permission granted by the Turkish Ministry for Culture.

References [1] M. Andaloro, Araştirma Sonuçlari Toplantisi. 2009, 26, 187–200. [2] M. Andaloro, Araştirma Sonuçlari Toplantisi, Denizli. 2010, 27, 517–535. [3] M. Andaloro, Araştirma Sonuçlari Toplantisi. 2011, 28, 155–172. [4] C. Pelosi, U. Santamaria, G. Agresti, F. Castro, D. Lotti, P. Pogliani, Arkeometri Sonuclari Toplantisi. 2010, 25, 535–552. [5] C. Pelosi, G. Agresti, M. Andaloro, P. Baraldi, P. Pogliani, U. Santamaria, e-Preservation Science, accepted 6. 2. 2013, in press.

165 Book of Abstracts P44

Vibrational characterization of the new gemstone Pezzottaite

Erica Lambruschi,1* Danilo Bersani,1 Pier Paolo Lottici,1 Giacomo Diego Gatta,2,3 Ilaria Adamo3

1 Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Parma, Parma, Italy, +39 0521905239, [email protected]. 2 Dipartimento di Scienze della Terra, Università degli Studi di Milano, Milano, Italy 3 CNR-Istituto per la Dinamica dei Processi Ambientali, Milano, Italy

Pezzottaite is a rare Cs-bearing mineral with ideal composition Cs(Be2Li)Al2Si6O18, discovered in November 2002. Pezzottaite is probably the only new mineral species with some relevance in gemology, thanks to its optical properties, rarity and beauty.

It is considered as a member of the “beryl group”, along with beryl sensu-scricto (Be3Al2Si6O18), bazzite

(Be3Sc2Si6O18), stoppaniite (Be3Fe2Si6O18) and indialite (Mg2Al3(AlSi5O18)). The chemical composition and the spectroscopic features of pezzottaite from Ambatovita (central Madagascar) and a Cs-rich beryl from Monte Capanne (Isolad’Elba, Italy) were investigated by standard gemmological analysis, electron microprobe analysis in wavelength dispersive mode (EMPA-WDS), X-ray diffraction and micro-Raman spectroscopy. The density and the refractive index of pezzottaite were found to be higher than those of beryl due to the entrance of a large amount of alkali. However, an unambiguous distinction between pezzottaite and Cs-rich beryl cannot be done only on the basis of density and optical properties. Pezzottaite and Cs-rich beryl are usually distinguished on the basis of chemical analysis, considering

a conventional upper-limit of caesium in Cs-rich beryl of Cs2O ~ 9 wt%, or by X-ray diffraction, as pezzottaite has different symmetry. In any case, the discrimination is not easy and requires advanced and expensive techniques.

Chemical analysis of our samples showed an high amount of cesium (Cs2O 12.91 wt%) for pezzottaite, while the Cs-beryl has 1.27 wt%.

Figure 1. Raman spectra of pezzottaite (above) and Cs- Figure 2. Raman spectra of pezzottaite (above) and Cs-beryl beryl (below) in the region 100-1,200 cm-1. (below) in the region 3,500-3,650 cm-1.

RAA 2013 166 P44

The crystal structure of the samples has been investigated through X-ray diffraction. The pezzottaite has a trigonal symmetry (space group R-3c, with a~15.9 and c~27.8 Å), while beryl is hexagonal (space group P6/mcc, with a~9.2 and c~9.2 Å). The increase of cell parameters is due to the entrance of lithium,that replaces beryllium in the tethaedra. The replacement causes a positive charge deficit neutralized by cesium in the channels. The samples of pezzottaite and Cs-rich beryl were investigated by micro-Raman spectroscopy, a non- destructive and rapid tool of investigation. The un-polarized Raman spectrum of pezzottaite over the extended region 100-3,650 cm-1 was collected for the first time, and compared with the spectrum of a Cs-beryl (Figure 1 and 2). In particular, Cs-beryl has showed only an intense peak at 3604 cm-1, ascribable to H2O stretching vibrations. On the other hand, two weak Raman bands at 3,591 and 3,545 -1 cm ,ascribable to the fundamental H2O or OH stretching vibrations respectively, were observed, despite the mineral should be nominally anhydrous. The Raman spectroscopy was useful to understand the type of water (type “I” or type “II”) and then to evaluate presence of alkali in the channels. In addition, the Raman spectrum of pezzottaite shows two intense and characteristic bands at 110-112 cm-1 and 1,100 cm-1, which are not present in the beryl spectrum (Figure 1). Even if the true nature of the two bands is not completely understood, Raman spectroscopy appears to be a promising and inexpensive tool for a quicker identification of pezzottaite.

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Preliminary investigations by Raman microscopy, FTIR-ATR and ESEM of wall paintings from the tomb of Amenemonet (TT277), Qurnet Murai necropolis, Luxor, Egypt

Mohamed Abd El Hady 1*, Hussein Marey Mahmoud2

1 Department of Conservation, Faculty of Archaeology, Cairo University, Giza, Egypt, +386 1 2343 118, [email protected]. 2 Department of Conservation, Faculty of Archaeology, Cairo University, Egypt

The present paper reports preliminary results obtained from the application of different analytical techniques used to characterize samples of wall paintings from the tomb of Amenemonet (TT277) (the 19th dynasty, c. 1298-1187 BC) , Qurnet Murai necropolis, Luxor, Egypt. The samples were analyzed by optical microscopy (OM), environmental scanning electron microscopy (ESEM) coupled with an energy dispersive X-ray analysis system (EDAX), Raman microscopy and Fourier transform infrared spectroscopy equipped with an attenuated total reflectance detector (FTIR-ATR). Thanks to the microscopic unit attached to Raman instrument, spectra were recorded on individual grains in the samples. The analyses on the samples have been undertaken on the rough samples without any kind of preparation. The chromatic palette used in the tomb was identified as: Egyptian blue (cuprorivaite), red ochre (haematite), yellow ochre (goethite) and carbon black (from a vegetable origin). A green tonality was obtained through a mixture of Egyptian blue and yellow ochre. The analysis showed that the preparation layer is almost made of pure gypsum. The Raman spectrum recorded on the red

pigment sample (see Fig. 1) represents typical peaks of haematite (α-Fe2O3) at 226, 298, 417 and 614 cm–1 (Goodall et al. 2007; Marey Mahmoud, 2011). Moreover, the strong band at 417cm–1 indicates a well-crystallised haematite. The Raman spectrum of the yellow pigment sample shows bands at 395, 305 and 557 cm–1 are for goethite (α-FeOOH). Several amounts of titanium dioxide phase anatase were detected in the yellow pigment samples which can be a contaminant in natural iron oxide deposits. EDAX microanalysis obtained on the red and yellow pigment samples shows the presence of signal of iron together with minor amounts of Al and Si. The later ones could be due to the existence of an aluminosilicate material (e.g. clay minerals which could be primary accessory minerals in ochre pigments). In the case of blue pigment samples, the pigment fluoresced very strongly when it was excited at 785 nm. For this, the identification of the blue pigment was based mainly on ESEM-EDAX

Figure 1. ESEM image and µ-Raman spectrum obtained on the red pigment sample.

RAA 2013 168 P45 and FTIR-ATR analyses which indeed confirm the presence of cuprorivaite. The FTIR-ATR spectrum recorded on the pigment shows characteristic peaks in the region 1000 and 1050 cm−1 are attributed to Si−O−Si stretching vibrations. In this region, Egyptian blue gives raise to a typical triplet bands, medium intensity bands at 1003, 1049 cm−1 and low intensity bands at 1157 and 1215 cm−1. The Raman spectrum recorded on the black pigment contains two characteristic broad bands for carbon black centred at 1345 and 1583 cm–1. The Raman analyses detected no band at 960 cm–1, the wave number of the stretching of the phosphate ion 3– [PO4] , so that the presence of ivory black and bone black may be excluded (Ospitali et al. 2006). This indicates that the carbon was obtained from a vegetable origin. FTIR-ATR analysis on the pigment samples showed the spectra are consistent with a proteinaceous material (amide II vibration at 1541 and 1578 cm–1). The absence of carbonyl bands at c. 1730 cm–1 suggests that the protein may be the animal glue. In most of samples, the content of animal glue was not confirmed because the amide I and II bands are masked by the broad bands of calcium sulphate, oxalate and carbonate. Further analysis using gas chromatography mass spectrometry (GC/MS) will be useful to identify the proteins in the sample. In conclusion, the obtained results will be discussed and compared with previous finds from ancient Egyptian monuments dating back to the same period.

References [1] R. A. Goodall, J. Hall, H. G. M. Edwards, R. J. Sharer, R. Viel, P. M. Fredericks, Journal of Archaeological Science. 2007, 34(4), 666–673. [2] H. Marey Mahmoud, Mediterranean Archaeology and Archaeometry. 2011, 11(1), 99–106. [3] F. Ospitali, D. C. Smith, M. Lorblanchet, J. of Raman Spectrosc. 2006, 37, 1063–1071.

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Physico-chemical characteristics of Predynastic pottery objects from Maadi Egypt

Mohamed Abd El Hady,1 A. Abdel-Motelib,2 Rabea Radi,3 Shaimaa Sayed4*

1 Faculty of Archaeology, Cairo University, Giza, Egypt, +0201064945338, [email protected] 2 Geology Department, Faculty of Science, Cairo University, Giza, Egypt, +0201223314921, [email protected] 3 Ministry state of Antiquities, Giza, Egypt, +0201002079624, [email protected] 4 Ministry state of Antiquities, Egypt, +0201007256560, [email protected]

Pottery manufacture is considered one of the oldest techniques practiced by human beings all over the world through ages. This is why that the archeological missions working in the ancient sites found a lot of pottery objects of different kinds and types which were processed by different techniques. The archeological pottery objects discovered in Maadi Sites in Egypt are mostly dating back to Predynastic Period about 3500 BC (Naqada Culture, Early Bronze Age). These objects are very rare either in Egypt or in international museums but they are unique and of great archaeological value. The chosen pottery objects were investigated and analyzed using polarized microscope, XRD analysis, and SEM techniques. The present research focuses on the processes and techniques of this type of pottery and illustrates its physio-chemical properties which varied greatly due to heterogeneity of the raw materials used in manufacturing as revealed from the obtained results. Moreover the results show that the incompletely fired samples contain clays, iron and titanium oxides, carbonates, quartz silt and organic materials while the completely fired samples are composed of chlorite, Meta kaolinite and quartz. On the other hand the present research focuses the light on identifying the deterioration products presenting in these archaeological objects. The obtained results showed that these objects seriously deteriorated due to due to physico-chemical and biological deterioration factors.

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Raman Database of Corrosion Products as a powerful tool in art and archaeology

Serena Campodonico,1,2* Giorgia Ghiara,1 Paolo Piccardo,1 Maria Maddalena Carnasciali1,2

1 University of Genoa, Department of Chemistry and Industrial Chemistry (DCCI), Italy, +39 010 3536088, +39 010 3538733, [email protected] 2 Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Firenze, Italy

The employment of Raman spectroscopy is well known in the field of art and archaeology,[1] being this non-destructive type of analysis also practicable with portable instruments if necessary. It is in fact known that elemental analysis cannot provide a precise and univocal answer in the detection of organic and inorganic compounds and many other analytical techniques (as X-Ray Powder Diffraction – XRD – for instance) are destructive and needing a sample taking, that for artistic and archeological objects is not frequently possible to obtain.

Even though significant progress has been made in the construction of Raman spectral databases of historical materials, many of these ‘reference’ spectra come from isolated incidents belonging to modern materials which do not focus their attention specifically on corrosion products. Accordingly, even if literature spectra represent a good starting point for the identification of unknown phases, the presented research mainly focuses on the collection of different spectra of corrosion products of a restricted area of materials (metallic materials) in order to help researcher and conservator scientists in their work of characterization and study of deterioration mechanisms and of conservative conditions of artistic and archaeological materials.

The main purpose of the research is to compare real cases coming from different scientific contexts, from cultural heritage to industrial applications (archaeological, ethnological, historical. modern, industrial), with standard samples (powders and minerals) and to realize a complete and exhaustive Raman library in the field of corrosion, where this tool has not been recognized as powerful as it possibly could become, yet. For example, the specific and non-destructive identification of minute quantities of material can provide the archaeologist invaluable information regarding an artefact including its authenticity, provenance, manufacturing technology, trade patterns, state of preservation and in some cases, approximate age.

By the analysis of minerals, powders, artistic and archaeological metallic artifacts it was also possible to give a direct proof of corrosive mechanisms and an immediate term of comparison since the suitability of the modern reference spectra for identifying aged samples has not been fully tested. For instance, samples found in archaeological context are likely to be natural products of inherent chemical variability which have undergone traditional processing, subsequent ageing and possible degradation and appearing variable in stoichiometry their Raman spectra are likely to reflect this variability - e.g. a mixture of tin and copper oxides forming on the surface of tin bronze objects.

Following this line, part of the research aim was also to better understand all the possible differences in spectral signal of as many real cases as possible, homemade powders and selected minerals associated to all kind of corrosion mechanisms involving metallic artifacts by modifying certain parameters as

171 Book of Abstracts P47 corrosion products status, growth degree, flaws and defects, mixed forms, etc… Moreover the choice of the laser excitation source has to be taken into account each time a spectrum is obtained. It is possible in fact not being able to identify the same corrosion product on a specimen surface due to the change of laser wavelenght applied. The akaganeite spectrum shown in Figure 1 emphasizes the difficulties in its identification by comparisons to literature spectra which differ in relative intensities using a different excitation source. Each time such problems occur the possibility of using a Raman database of known corrosion products offers more reliable answers.

Figure 1. Raman spectrum of Akaganeite (β-FeOOH), corrosion product rarely found on iron artifacts.

Analyses were undertaken at the Department of Chemistry and Industrial Chemistry (DCCI) with a Renishaw Raman System 2000 coupled with an optical microscope and a red He-Ne laser applying same laser parameters as gain, power, accumulations.

The obtained database will soon be available on-line and shared by all research users.

References [1] L. Bellot-Gurlet, S. Pagès-Camagna, C. Coupry. J. of Raman Spectrosc. 2006, 37, 962–965. .

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Micro-Raman as a powerful non-destructive technique to characterize ethonological objects from D’Albertis Castle Museum of World Cultures in Genova

Serena Campodonico,1,2* Giorgia Ghiara,1 Maria Maddalena Carnasciali,1,2 Camilla De Palma3

1 University of Genova, Department of Chemistry and Industrial Chemistry (DCCI), Italy, [email protected] 2 Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Firenze, Italy 3 D’Albertis Castle Museum of World Cultures, Genova, Italy

In recent periods an awakened interest is grown on non - invasive techniques employed in the field of art and archaeology – mainly focusing on the identification of pigments, binding media, etc…or on the characterization of degradation processes of objects showing some cultural or ethnological value. Characterization of cultural heritage artifacts by the use of non - invasive procedures has widely been discussed, as shown in many publications and books. Energy Dispersive or Wavelength Dispersive X - Ray Fluorescence (EDXRF or WDXRF) measurements have often been associated to more traditional sample-requiring analyses – e.g. X-Ray Diffraction (XRD) or Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy (SEM-EDXS) – in order to gain preliminary compositional information.[1] Yet only in recent times Raman spectroscopy has roused a wide range of interest because of his great potential as non-destructive technique in the field of diagnostics.[2]

The D’Albertis Castle Museum of World Cultures in Genoa represents a wonderful example of ethnological collection. A large number of different types of objects - of unknown nature and/or composition -, have been collected by the Captain D’Albertis during its journeys across lands and seas all around the world between the end of the XIX century and the beginning of the XX century. This remarkable collection, like a “cabinet of curiosities”, gave us the possibility to discover artworks of great interest from the conservative point of view. Since the possibility to analyze them has been limited under the sine qua non condition of non-destructive analysis without sample taking, the employment of microRaman spectroscopy has been considered perfect for the research.

MicroRaman technique resulted as a powerful tool, coupled also with a p-XRF instrument for the material characterization of a selection of small metal objects taken from the collection inside the Sala Colombiana of the museum. These metal objects have been chosen for their different provenance, date, type of metal/alloy, use, conservation status, shape and color. Analyses have been carried out in the laboratories of the Department of Chemistry and Industrial Chemistry (DCCI) with a Renishaw Raman System 2000 coupled with an optical microscope and a red He-Ne laser – applying changes in laser parameters e.g. gain, power, accumulations. The obtained results not only allowed us to identify metal composition – e.g. an unknown bracelet constituted by a metallic twist of brass and iron with copper plates was identified by detecting iron and copper corrosion products – but with the help of this invaluable technique it was possible to investigate corrosion products depositing on the object surface and correlating them directly to the environmental conditions they were exposed to – e.g. wet and dry cycles, marine atmospheres, burial.

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Figure 1. LOM and Stereo micrographs of an African bracelet Figure 2. From the analysis it was possible to see the heterogeneous from Rhodesia, Zimbabwe. nature of corrosion products, which gave information on the elemental composition of the bracelet itself.

Acknowledgements The authors would like to thank the Soprintendenza ai Beni Artistici e Archeologici of Genova and the D’Albertis Castle Museum of World Cultures for giving the possibility to undertake this research project.

References [1] V. Desnica, K. Škarić, D. Jembrih-Simbuerger, S. Fazinić, M. Jakšić, D. Mudronja, Appl. Phys. A. 2008, 92(1), 19–23. [2] L. Bellot-Gurlet, S. Pagès-Camagna, C. Coupry, J. of Raman Spectrosc. 2006, 37, 962–965.

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Micro ATR-IR study of pollutions affecting radiocarbon dating of ancient Egyptian mummies

Céline Paris,1 Anita Quiles,2,3* Ludovic Bellot-Gurlet,1 Emmanuelle Delqué- Količ,3 Cathy Vieillescazes,4 Matthieu Ménager,4 Clothilde Comby-Zerbino,3 Karine Madrigal5

1 LADIR UMR 7075 CNRS-UPMC, Université Pierre et Marie Curie, Paris, France, [email protected] 2 LSCE, Bât. 12, avenue de la Terrasse, Gif-sur-Yvette, France, [email protected] 3 LMC14 – UMS 2572 – CEA de Saclay, Gif-sur-Yvette, France 4 Université d’Avignon et des Pays de Vaucluse, IMBE, Avignon, France 5 Musée des Confluences de Lyon, Lyon, France

In the frame of a study on the establishement of an absolute chronology for ancient Egypt[1] the Laboratoire de Mesure du Carbone 14 has dated by 14C textiles and body fragments of Egyptian mummies conserved at the Musée des Confluences de Lyon (France). Ages older than expected were obtained for two mummies. Further examinations let suspecting some late rituals possibly involving the use of bitumen which could explain the aging of 14C results by fossil carbon. As the use of bitumen could have been used for mummification rituals in the graeco-roman period, the establishment of easily implemented procedure for detection and removal of aging pollution will offer new perspectives to ensure radiocarbon dating in these contexts. Complementary analyses were then performed to look for bitumen identification; in parallel some specific procedures for sample preparation were evaluated to remove fossil organic pollution before dating. Because of its flexible implementation, its low requirement in sample amount and sensitivity for organics, micro-ATR IR spectroscopy (micro-Attenuated Total Reflexion Infrared) was privileged in this study to detect and identify aging’s contaminant. In order to facilitate organics identification, we focused on the study of mummy’s strips made of linen. A first study of “contaminated” and “none contaminated” linen samples (in respect to their radiocarbon age) underline the presence of a “lipidic” organic substance. It is characterised by a specific profile of the CH massif and an acid group (with a band at 1707 cm-1). A comparison with modern test samples imbibed by bitumen of Judea provides a very similar vibrational signature. On the other hand, various protocols of ultrasound-assisted organic component extraction were carried out on a set of modern lin fabric impregnated with bitumen. Micro ATR-IR analyses and 14C measurements were then performed to evaluate the sample purification. The efficiency validation will allow proposing a pre-treatment procedure for samples in which aging pollutions could be suspected by a preliminary spectroscopic analysis.

References [1] A. Quiles, E. Aubourg, B. Berthier, E. Delque-Količ, G. Pierrat-Bonnefois, M. W. Dee, G. Andreu-Lanoë, C. Bronk Ramsey, C. Moreau. J. of Archaeological Science. 2013, 40, 423.

175 Book of Abstracts P50

Raman Scanning of Biblical Period Ostraca

Arie Shaus,1* Barak Sober, 2 Omer Tzang,3 Zvi Ioffe,4 Ori Cheshnovsky,5 Israel Finkelstein,6 Eliezer Piasetzky7

1 The Department of Applied Mathematics, Tel Aviv University, [email protected] 2 The Department of Applied Mathematics, Tel Aviv University, [email protected] 3 School of Chemistry, Tel Aviv University. [email protected] 4 School of Chemistry, Tel Aviv University. 5 School of Chemistry, Tel Aviv University, [email protected] 6 The Jacob M. Alkow Department of Archaeology and Ancient Near Eastern Civilizations, Tel Aviv University, [email protected] 7 The Sackler School of Physics and Astronomy, Tel Aviv University, [email protected]

The ink of ostraca inscriptions tends to fade significantly over time. Therefore, acquiring the most legible image of an ostracon promptly after the excavation is crucial for its documentation. Unfortunately, existing image acquisition techniques were not able to cope with the challenging medium in a satisfying manner. Preliminary experimentation showed that Raman-based methods bear the potential for ink identification. Consequently, a novel Raman scanning device suitable for this task was constructed and tested on ostracon from Horvat ‘Uza in the Beersheba Valley. The mapping was based on new computational peak-finding tools, producing a binary inscription image. Our experiments showed the promise in these techniques.

Acknowledgements The research leading to these results received funding from the F.I.R.S.T. (Bikura) Individual Grant no. 644/08. The research was also partially funded by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no. 229418. This study was also supported by a generous donation of Mr. Jacques Chahine, made through the French Friends of Tel Aviv University. Arie Shaus is grateful to the Azrieli Foundation for the award of an Azrieli Fellowship.

Figure 1. a.) Raman complex diagram: The laser (red) was collimated, reflected by a prism onto the objective lens. The scattered light (pink) was collected and passed through a beam splitter (BS) and a notch filter (NF). Light that travelled through the notch filter was collimated by a tube lens on to an optical fiber and entered the spectrograph. b.) General drawing of the Raman microscope system.

RAA 2013 176 P50

Figure 2. Example of Horvat ‘Uza ostracon scan a.) Area of interest b.) Overlaid Raman scan results c.) Scan results after post-processing (median filter).

References [1] S. Faigenbaum, B. Sober, A. Shaus, M. Moinester, E. Piasetzky, E. Bearman, M. Cordonsky, Finkelstein I. “Multispectral Images of Ostraca: Acquisition and Analysis”. J. of Archaeological Science, 2012, 93(12), 3581–3590. [2] I. Finkelstein, E. Boaretto, S. Ben Dor Evian, D. Cabanes, M. Cabanes, A. Eliyahu, S. Faigenbaum, Y. Gadot, D. Langgut, M. Martin, M. Meiri, D. Namdar, L. Sapir-Hen, R. Shahack-Gross, A. Shaus, B. Sober, M. Tofollo, N. Yahalom-Mack, L. Zapassky, S. Weiner, “Reconstructing Ancient Israel: Integrating Macro- and Micro-archaeology”, Hebrew Bible and Ancient Israel. 2012, 1, 133–150. [3] B. W. Porter, R. J. Speakman, “Reading Moabite Pigments with Laser Ablation ICP-MS: A New Arcbaeometric Technique for Near Eastern Archaeology”, Near Eastern Archaeology. 2008, 71(14), 238– 242. [4] O. Tzang, K. Kfir, E. Flaxer, O. Cheshnovsky, S. Einav, “Detection of Microcalcification in Tissue by Raman Spectroscopy”, Cardiovascular Engineering and Technology. 2011, 2(3), 228–233.

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Analyses of pigments from 4th century B.C. the Shushmanets tombs in Bulgaria

Cristina Aibéo,1 Stefan Simon,1 Diana Georgova,2 Veska Kameranova, Ivelina Pavlova, Angel Pavlov

1 Rathgen Research Laboratory – National Museums Berlin, Germany, +49 30 266427100, [email protected] 2 National Institute of Archaeology with Museum – BAS, Sofia, Bulgaria, +359 2 988 24 06 3 CRA – Centre for Restoration of Art Works, Sofia, Bulgaria, +359 887262718

The Thracian tomb-temple under the “Shoushmanets” tumulus was discovered in 1996. The tumulus belongs to the huge necropolis of the Odryain kingdom in the Kazanlak valley and dates back to the 4th century BC. The tomb is one of the most representative works of the Thracian architecture. It is typical for the South Thracian lands tholos type, but is unique with its architectural solutions.

It is built of large, well-formed stone blocks and consists of a wide dromos, an antechamber with a semi-cylindrical vault, supported by a Doric column with Ionic capital and a circular main chamber with a small bed on the opposite to the entrance side. Although the tholos tomb is the most characteristic architectural type in Southern Thrace, the tomb under Shushmanets is unique with the central column in the burial chamber ending with a large disk as a Sun symbol. It is the only Balkan example of a series of Megalithic and Early Iron Age tombs with central column known from the Mediterranean world - from Menorca to the Etruscan territories. The main chamber is decorated with semi-columns in Doric style and vertical flutes. The floors and the walls were plastered in white in several layers. The discovery during restoration works of an earlier omphalos (altar), plastered on the floor of the central chamber, the sacrifices in the antechamber of four horses and two dogs, as well as the small bed in the chamber, suitable rather for sitting, confirm its function as tomb-temple, in which periodically different mysteries, connected with the Orphic mysteries and beliefs in the astral immortality had been performed. The interdisciplinary approaches are the only possibility after the archaeological research to throw new light on the story of the tomb temple, on its function, and on the character of the mysteries performed in it. The characterisation of mortars[1] was already published; the present paper is about the characterisation of the tomb pigments and its comparison with similar constructions from the same period.[2] The non- destructive technique of Raman spectroscopy was used for this purpose. Spectra were acquired with a Horiba XploRa Raman-Microscope, fitted with lasers of wavelength 532 nm, 638 nm and 785 nm. The power of each laser was 25 mW (532 nm), 24 mW (638 nm) and 90 mW (785 nm). The maximal spatial resolution was 1 µm. In the spectra, Raman shifts are given in cm-1.

References [1] Eugenia Tarassova et al., National Conference with international participation “GEOSCIENCES 2012”, BULGARIAN GEOLOGICAL SOCIETY, 2012, 157–158. [2] Koinova-Arnaudova, Lorinka, K. Krusstev, M. Enev, L. Kinova, I. Penev, The Thracian Tomb near Sveshtary village, The conservation of cultural heritage for sustainable development, ed. European Communities, ICSC, 2003, 291–295.

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Raman Spectroscopic Study of the Formation of Fossil Resins Analogs

Oscar R. Montoro,1* Mercedes Taravillo,1 Margarita San Andrés,2 José Manuel de la Roja,2 Alejandro F. Barrero,3 Pilar Arteaga,3 Valentín G. Baonza1

1 MALTA-Consolider Team & QUIMAPRES Team, Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Spain, +34 91 394 42 62, ormontoro@quim. ucm.es 2 Universidad Complutense, Facultad de Bellas Artes, Dpto. de Pintura-Restauración, Madrid, Spain, +34 91 394 36 40, [email protected] 3 Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Granada, Spain, +34 958 24 33 18, [email protected]

Fossils resins are gemstones of organic nature that have survived until ours days. The vast majority of fossil resins derives from natural terpene-based polymers, and therefore has an organic origin. These are classified into five classes, of which the most important is called Class I, that it is composed by monomers of labdanics family (a type of diterpene) polymerized, primarily of polymerized communic acids [1,2], whose chemical structures are shown in Figure 1. The reaction processes that have taken place throughout the ages until formation of fossil resins are complex and little studied, therefore they are poorly understood. Existing studies have focused on the possible high temperature polymerization in the family of communic acids, which are precursors for a large majority of Class Ia fossil resins.[3]

Figure 1. Communic acids. R = -COOH; trans-, cis-, mirceo-.

The main purpose of this work is to provide spectroscopic evidences of possible chemical pathways that took place in the formation of fossil resins, through the reactivity of pure communic acids at different temperatures. We shall focus here on trans-, cis- and mirceo- communic acids. The maturing reactions proposed in the literature are mainly polymerizations between the conjugated double bonds and subsequently internal molecular reactions in the initial polymer formation. The samples were characterized by a confocal micro-Raman spectrometer (BWTEK VoyageTM BWS435- 532SY) coupled to an Olympus BX51 microscope. Raman spectra were taken by using a 532.0 nm laser line. Our studies for these pure compounds were completed with Fourier Transform infrared (FTIR), ATR-FTIR and differential scanning calorimetry measurements. We have performed our study in each pure component separately. Figure 2 depicts some Raman spectra measured at selected temperatures for the trans-communic acid. An increase in fluorescence of the sample is observed above the melting temperature of these acids (around 170–180 °C in the case of trans-communic acid), which results in a significant change of color of the initial mixture (white to yellow-amber for the recovered sample after heating cycle). We will analyze the temperature-induced

179 Book of Abstracts changes in the different Raman features and the possible reactivity that has taken place. In addition, we have focused in the spectral regions of the C-H stretches and bending fingerprint, since this is key spectral region for understanding the formation of fossil resins. Such features usually give information of the geographical origin and antiquity of the specimens, and they may assist to distinguish real fossil resins from imitations. Finally, the spectroscopic results have been compared with a number of fossil resins of different geological dating.

Figure 2. Raman spectra of trans-communic acids

at selected temperatures. λexc = 532 nm.

Acknowledgement This work has been funded by the Spanish Ministry of Science and Innovation under Projects CTQ2010- 20831, CTQ2012-38599-C02-02 and MALTA-Consolider Ingenio 2010(CSD2007–00045). The authors are also grateful to the Science and Technology of Heritage Conservation Laboratory Network (RedLabPat), CEI, Moncloa Campus (UCM-UPM) and Comunidad de Madrid and EU through the QUIMAPRES-S2009/PPQ-1551 program.

References [1] K. B. Anderson, R. E. Winans, R. E Botto, Organic Geochemistry. 1992, 18, 829–841. [2] A. F. Barrero, M. M. Herrador, P. Arteaga, J. F. Arteaga, Molecules. 2012, 17, 1448–1467. [3] R. M. Carman, D. E. Cowley, R.A. Marty, Australian Journal of Chemistry. 1970, 23, 1655–1665.

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Pigments from Templo Pintado (Pachacamac, Perú) investigated by Raman Microscopy

Dalva Lúcia Araújo de Faria,1*Gianella Pacheco,2 Denise Pozzi-Escot,2 Marta S. Maier,3 Valeria Careaga3

1 Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil, +55 11 30913853, [email protected] 2 Museo de sitio de Pachacamac, Ministerio de Cultura, Lima Perú, [email protected], [email protected]. 3 UMYMFOR and Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Buenos Aires, Argentina, [email protected], [email protected]

Pachacamac is a complex and vast archaeological site on the coast of Perú, 31 km south from Lima (Lat.12° 15’ 29” South Long. 76° 54’ 00” West). Its origin goes back to 200 CE and was taken over from the Ychma by the Incas around 1470 CE. As a religious and pilgrimage site, among the most significant buildings are the Templo Pintado (Painted Temple) and Templo del Sol (Temple of the Sun). The former is a 50 m high and 100 m wide adobe pyramid, with 3 sides made of a succession of giant steps (1 m high); the fronts of such staggered building are decorated with people, plants, birds and fish paintings,

Figure 1. Painted wall at Templo Pintado, showing severe deterioration (left) and adobe fragment with a bluish-green paint (right).

colored in red, yellow and bluish-green mineral pigments, outlined in black1(Fig. 1). The current efforts in the preservation of such magnificent archaeological site demand a better understanding on the materials and techniques originally employed. This work reports the results of pigment analysis using Raman Microscopy and XRD. The investigated samples were 5 painted adobe fragments from Templo Pintado (north wall) and 4 minerals collected in quarries at the site area (Table 1). The painted fragments were investigated by Raman Microscopy (632.8 nm, 785 nm and 1064 nm excitation) and the reference minerals were also characterized by XRD.

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Table 1. Samples identification and description

Sample ID Sample Description TP-029a Painted fragment (several layers): red, pale yellow and bluish-green TP-029b Painted fragment: red and orange pigments TP-029c Painted fragment: red paint TP-029d Painted fragment: bluish-green paint with black trace TP-029e Stone bluish-green fragment with porous and irregular surface MC1 Yellow pigment from quarry MC2 Red pigment from quarry MC3 Pale yellow pigment from quarry MC4 Pale red pigment from quarry

The main issues to be addressed in the present investigation are: (i) the minerals from the quarries (MC1 to MC4) and the pigments in the painted fragments (TP-029a to TP-029e) are the same? (ii) the bluish-green pigment on sample TP-029d and TP-029e are the same? (iii) the black colored pigment in sample TP-029d is carbon? (iv) which organic binders, if any, were used to prepare the paintings? 2 An extensive Raman Microscopy investigation revealed that the red pigments were hematite (α-Fe2O3) in both MC and TP samples, but bands assigned to α-quartz (465 cm-1) and magnesium sulfate (main band at 1006 cm-1) were also identified. Curiously, XRD did not show the presence of any crystalline compound (including hematite) in none of the red samples (MC2 and MC4). Cinnabar was not detected. Black pigment in TP-029d is carbon (broad bands at ca.1360 and 1580 cm-1), although in a much smaller extension, magnetite (Fe3O4)was also identified; it is very likely that the latter is a contamination, considering the minerals used in the paint. Concerning the bluish-green pigment, 2+ 3+ despite the luminescent background it was possible to identify celadonite (K(Mg,Fe )Fe (Si4O10)(OH)2) in both painted adobe and stone fragment, using Raman Microscopy and XRD. Furthermore, in the bluish area of the adobe fragment, a very small (300-400 µm) piece of bright blue bird feather was found. In conclusion, Raman Microscopy and XRD were used to show that the minerals collected in quarries at the Pachacamac site and the paints on the adobe fragments are mostly silicates; in the case of the red pigment, hematite was identified by Raman Microscopy but not by XRD, indicating a low degree of crystallinity. It is thus very likely that the pigments used in Templo Pintado were from the local quarries. It was also shown that the bluish-green pigment in sample TP-029d and TP-029e are the same and corresponds to celadonite. A small fragment of blue bird feather suggests that the walls decorations had more than mineral pigments. Finally, the pigment in the black trace in sample TP- 029d is carbon.

References [1] J. C. Muelle, R. Wells, Revista del MuseoNacional. 1939, 8, 265. [2] D. L. A. de Faria, S. Venâncio Silva, M.n Spectroscopy. 2012, 43, 1811–1816.

RAA 2013 182 P54

Lithic tools raw materials recognition by Raman spectroscopy of Palaeolitihic artifacts

Sonia Murcia-Mascaros,1*Clodoaldo Roldan,1 Valentin Villaverde,2 Aleix Eixea,2 Jorgelina Carballo1

1 Materials Science Institute, University of Valencia, ICMUV, Paterna, Valencia, Spain, [email protected] 2 Departamento de Prehistoria y Arqueología, Universityof Valencia, Spain

A preliminary characterisation of the lithic raw-materials found in levels I-III of the Middle Paleolithic site of Abrigo de la Quebrada (Valencia, Spain) is reported. The artifacts were excavated in the field seasons of 2004 and 2007, have already been the object of a preliminary technological assessment and their analysis has been preceded by a survey of local procurement sources, carried out in 2008. We recognized six raw-material categories by means of a macroscopic study.[1] A representative set of these lithic tools has been nondestructively investigated by means of Raman spectroscopy. The characterization of the mineral composition allows the assessment of the resource catchments and mobility patterns of the human groups that used the shelter at this time.[2] It was found that a-quartz crystallites, in association with the silica mineral moganite and the free Si–O vibrations of non-bridging Si–OH from silanole, are present on raw materials and could be used to distinctive fingerprint in these chert samples.[3]

Figure 1. Lithictoolsfromthe Abrigo de la Quebrada, Chelva, Valencia (middlePalaeolithic).

References [1] V. Eixea, V. Villaverde, J. Zilhão, Trabajos de Prehistoria, 2011, 68, 65. [2] V. Hernández, S. Jorge-Villar, C. Capel Ferrón, F. J. Medianero, J. Ramos, G.C. Weniger, S. Domínguez-Bella, J. Linstaedter, P. Cantalejo, M. Espejoi, J. J. Durán Valsero, J. RamanSpectrosc. 2012, 43, 1651. [3] P. Schmidt, L. Bellot-Gurlet, A. Slodczyk, F. Frohlich, PhysChem Minerals. 2012, 39, 455.

183 Book of Abstracts P55

Raman characterization on historical mortar. Crossing data with XRD and Color Measurements

Dorotea Fontana,1,2* Anna Maria Gueli,1 Giuseppe Stella,3,4 Sebastiano Olindo Troja,1 Maria Brai,2 Jorge Dinis,4 Luis Almeida,3 Lilia Basílio,3 Miguel Almeida3

1 PH3DRA Laboratories (PHysics for Dating Diagnostic Dosimetry Research and Applications), Dipartimento di Fisica e Astronomia, Università di Catania & INFN Sezione di Catania, Catania, Italy, [email protected] 2 Laboratorio di Fisica e Tecnologie relative – UniNetLab, Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Palermo, Italy 3 iDryas / Dryas Octopetala, Coimbra, Portugal 4 Earth Sciences Dep., Faculty of Science and Technology, University of Coimbra, IMAR-CMA, Coimbra, Portugal

Raman spectroscopy is becoming a popular technique to classify samples of building materials such as mortars by molecular analysis, thus providing invaluable information about these material’s composition and manufacture techniques, relevant for preservation operations and/or dating and technical studies.[1] 2+ Carbonation takes place in building materials when atmospheric CO2 reacts with Ca present in the pore solution. Of the three crystallized forms of calcium carbonate, calcite is the most thermodynamically stable. Raman spectroscopy is a very useful technique for distinguishing between calcite, aragonite and vaterite.[2] In the present study, micro-Raman techniques are used for the first time to establish the existence of various forms of calcium carbonate in lime mortar collected from the Convento de S. Francisco (Coimbra, Portugal). Measurements were carried out using a micro-Raman system equipped with 542 nm and 785 nm laser sources excitation wavelenghts. Raman results were crossed with macroscopic interpretation of the building’s structure, mineralogical characterization by XRD and colorimetric data. The mineralogical characterization was based on X-ray diffraction (XRD) with a Philips X’Pert Pro PW3710 diffractometer equipped with a with CuK_ radiation, operating at 40 kV and 20 mA. An experimental contact spectrophotometric method, with Spectral Reflectance Factor SRF( ), was used for colorimetric characterization, using a portable Konica-Minolta CM2600D instrument equipped with an integrating sphere in the geometry d/8°, that produces a mathematical calculation of the tristimulus values, choice the measurement geometry, the type of illuminant and the standard observer amongst those regulated by the Commission Internationale de l’éclairage (CIE). Preliminary results on mortar characterization showed two different colorimetric groups, both structural and mineralogical.

References [1] O. Gómez-Laserna, N. Prieto-Taboada, I. Ibarrondo, I. Martínez-Arkarazo, M. A. Olazabal, J. M. Madariaga, Brick and Mortar Research, 2012, pp. 195–214. [2] S. Martinez-Ramirez, S. Sanchez-Cortes, J. V. Garcia-Ramos, C. Domingo, C. Fortes, M. T. Blanco-Varela, Cement and Conrete Research, 2003, 33, 2063–2068.

RAA 2013 184 P56

Roman ceramics from Vicofertile (Parma, Italy): micro-Raman study of the heat diffusion during the production process

Elisa Adorni,1* Danilo Bersani,2 Pier Paolo Lottici,2 Talisa Cerasoli,2 Lorenzo Sambo,1 Irene Aliatis,2 Manuela Catarsi3

1 University of Parma, Department of Civil- Environmental Engineering and Architecture, Parma, Italy, +39 0521 905961, [email protected], [email protected] 2 University of Parma, Department of Physics and Earth Sciences, Parma, Italy, +39 0521 905239, [email protected], [email protected], [email protected] 3 Soprintendenza per i Beni Archeologici dell’Emilia-Romagna, Museo Archeologico Nazionale di Parma, Parma, Italy

The present work focuses on the archaeometric characterization of Roman ceramics from Vicofertile (Parma, north-west Italy), with the main aim of defining the production systems, the surface finishing and the origin of the clays and to identify the production areas, through a multi-methodological approach. In 2008, during the two-year campaign of excavations in the area of Vicofertile, five Roman villas of the end of the first century AD, modified till the Imperial age with the addition of wineries and furnaces, were discovered. From the villas, twenty-eight samples of Roman ceramics were selected: amphorae with seals, terra sigillata pottery with in plantapedis seals, fragments of thin-walled ceramics, black painted pottery and an antefix. The samples were mineralogically and petrographically analyzed to characterize the composition of temper, ceramic body and decorations. The use of micro-Raman spectroscopy, in particular for the identification and understanding the structural changes during a fire treatment, is well established.[1–5] In this article, in addition to the standard characterization of the components of ceramic body and surface, Raman mapping was extensively carried out along the thickness of the ceramic samples to define the heat distribution during the production process. The collected data were compared with the peculiar shape of the ceramics and the ancient types of kilns to compare the real distribution of heat and its effect on the ceramic artifacts.

Figure 1. Raman maps obtained from the main bands of feldspar, hematite and quartz on a cross section of a red Roman ceramic; brighter shade means larger peak intensity.

185 Book of Abstracts P56

References [1] P. Colomban, N. QuangLiem, G. Sagon, H. XuanTinh, T. Ba Hoành. J. of Cultural Heritage. 2003, 4, 187– 197. [2] P. Colomban, Applied Physics A. 2004, 79, 167–170. [3] D. Bersani, P. P. Lottici, S. Virgenti, A. Sodo, G. Malvestuto, A. Botti, E. Salvioli-Mariani, M. Tribaudino, F. Ospitali, M. Catarsi, J. of Raman Spectrosc. 2012, 41, 1266–1271. [4] Š. Pešková, V. Machovič, P. Procházka, Ceramics – Silikáty. 2011, 55, 410–417. [5] M. C. Zuluaga, A. Alonso-Olazabal, M. Olivares, L. Ortega, X. Murelaga, J. J. Bienes, A. Sarmiento, N. Etxebarria, J. of Raman Spectrosc. 2012, 43, 1811–1816.

RAA 2013 186 P57

Raman spectroscopic study on ancient glass beads found in Thailand archaeological sites

Krit Won-in,1 Yatima Thongkam,2 Pisutti Dararutana3*

1 Faculty of Science, Kasetsart University, Bangkok, Thailand 2 Faculty of Archaeology, Silpakorn University, Bangkok, Thailand 3 The Royal Thai Army Chemical School at the Royal Thai Army Chemical Department, Bangkok, Thailand

Various colors of glass beads excavated at different archaeological sites in Thailand such as Khlong Thom, Phu Khao Thong, Nang Yon, Thung Thuk, Khao Sri Vichai, Khao Sam Kaeo, Laem Pho, Hor- Ek, U-Thong and Huay Yai Tai were characterized non-destructively using Raman spectroscopy and X-ray fluorescence spectroscopy in order to determine the glass composition and the glass production technology in ancient time. The Raman spectra and XRF analysis classified that they were mostly alkali- based glass matrix. Some were lead-based glass. Their compositions were similar to Mediterranean, Islamic and Indian glasses, but higher concentration of aluminum. The colors were affected from the transition metal ions’ addition, such as copper, iron and manganese. Tin and lead were mostly presence in the opaque color samples. Consideration of the glass compositions and colorants, it could be assumed that there was some technological production which related with South-East Asia, South Asia, East Asia and Asia Minor. The information led to gain knowledge of the historic link of the long distance trade and exchange networks in the ancient maritime.

Acknowledgements This work was partly funded by the Faculty of Science at Kasetsart University. Authors were kindly thanks Captain Boonyarit Chansuwan from the 15th Regional Office of Fine Arts at Phuket Province for supporting the glass bead samples. The Maejo University at Chiang Mai and the Plasma and Beam Physics Research Facility at Chiang Mai University and the Gem and Jewelry Institute of Thailand (Public Organization) at Bangkok were also thanked for providing SEM-EDS, PIXE and Raman spectroscopy, respectively.

References [1] H. Veeraprsert, Khlong Thom: An ancient bead-manufacturing location and an ancient entrepot. Early Metallurgy, Trade and Urban Centres in Thailand and Southeast Asia, White Lotus: Bangkok, 1992.

187 Book of Abstracts P58

Identification of Neolithic jade found in Switzerland studied using Raman spectroscopy: Jadeite- vs. Omphacite- jade

Alessia Coccato,1 Stefanos Karampelas,2* Marie Wörle,3 Samuel van Willingen,4 Pierre Pétrequin5

1 Ghent University, Department of Archaeology, Ghent, Belgium, [email protected] 2 Gubelin Gem Lab, Lucerne, Switzerland, [email protected] 3 Suisse National Museum, Collection Centre, Affoltern am Albis, Switzerland 4 Suisse National Museum, Archeological Department, Zurich, Switzerland 5 Grande Rue 71, 70100 Gray, France

Objects made of jade, principally tools because of toughness of the rock, were used by humans since VI-IV millennia b.C. and are today found in excavations throughout the world (from Europe to far East as well as to Central and South America). In the course of time, jade became also a greatly appreciated gem (mainly to Far East). The term jade could signify different material. For example, for gemologists the term jade refer to virtually (>90%) amphibolitic and pyroxentitic monomineralic rocks; e.g., nephrite- and jadeite- jade respectively.[1] For archeologists, the term jade includes much more rocks, not forcibly monomineralic. Neolithic artifacts (e.g., axe-heads) made of “jade” were found all over the Europe.[2-5] Some Neolithic jade artifacts were also found in different places in Switzerland as well. The present study is focused to the identification by Raman spectroscopy of the sodic or sodic-calcic mono mineralic pyroxenites; i.e., the jadeite- and omphacite- jade. Twelve finished and semi-finished green stone objects coming from excavations carried out in

Figure 1. Ramanspectra with green laser of two rough samples collected recently. The bottom spectrum is of a jadeite-jade (main band at around 700 cm-1and a double band at around 1000 cm-1) and the upper spectrum is of anomphacite (main band at around 680 cm-1 and a double band at around 1020 cm-1).

Switzerland were selected among the collection of the Swiss National Museum (SNM) of Zurich, covering a wide range of materials and shapes. Some rough samples were recently collected (by one of the authors -PP-) from North Italy (Piedmont), where the jade was sourced during Neolithic. In Table 1 are reported some of the studied samples, their provenance, dimensions and description. Micro-Raman spectroscopy is useful for the characterization of jade (see some examples to [6,7] Raman spectra were acquired at the Gübelin Gem Lab (GGL) in Lucerne with a Renishaw Raman 1000 spectrometer coupled with a Leica DMLM optical microscope. All spectra were recorded using an excitation wavelength of 514 nm emitted by an argon ion laser (Ar+) and most were taken using standard mode (with 50x magnification). Raman spectra were acquired from 200 to 4000 cm−1 using a power of 5 mW on the sample, with an acquisition time of 60 seconds (3 cycles) and about 1.5 cm−1

RAA 2013 188 P58 resolution. Rayleigh scattering was blocked by a holographic notch filter, the backscattered light was dispersed on an 1800 grooves/mm holographic grating and the slit was set at 50 μm. More than one measurements were acquired to the most of samples and most of them were also measured with other means such us EDXRF and micro-FTIR (results not presented here). Raman spectra of omphacite-jade and jadeite-jade are slightly different, jadeite shows a main band at around 700 cm-1, as well as two weak bands around 1000 cm-1 and a group of peaks below 400 cm-1. [8,9] On the other hand, omphacite spectra present an intense band at around 680 cm-1, a broad band at around 1020 cm-1 and a group of peaks between 300 and 450 cm-1.[9,10] These differences are due to slight differences to their chemistry and structure.[11] Raman spectra of the rough reference samples recently collected in situ from the Northern Italy are presented in Figure 1. The studied archeological samples, which are similar macroscopically as well as under microscope, are not only jadeite-jade but also omphacite-jade. These results were cross-checked with other means (FTIR and/or EDXRF). Nowadays, jadeite-jade and omphacite-jade is not only found in Italy but also in Russia, Burma, Japan and Greece.[1]However, no remains of Neolithic minning or references to it, has yet been found.

References [1] G. E. Harlow, S. S. Sorensen, V. B. Sisson, Short Course Handbook Series. Ed. L. A. Groat, 2007, 207–254. [2] P. Petrequin, S. Cassen, C. Croutsch, O. Weller, Notae Praehistoricae. 1997, 17, 135–150. [3] P. Petrequin, M. Errera, A. M. Petrequin, European Journal of Archaeology. 2006, 9(1), 7–30. [4] C. D’Amico, R. Campana, G. Felice, M. Ghedini, European Journal of Mineralogy. 1995, 7(1), 29–41. [5] C. D’Amico, Archaeometry. 2005, 47(2), 232–252. [6] A. G. Badou, D. C. Smith, F. Gendron, J. of Archaelogical Science. 2002, 29 (8), 837–851. [7] D. C. Smith, Geomaterials in Cultural Heritage. Ed. M. Maggetti & B. Mesigga, 2006, 10–32. [8] H. Shurvell, L. Rintoul, P. M. Fredericks, The Internet Journal of Vibrational Spectroscopy. 2004, 5, http://www.ijvs.com/volume5/edition5/section2.html. [9] rruff.info [10] A. Katerinopoulou, M. Musso, G. Amthauer, Vibrational Spectroscopy. 2008, 48(2), 163–167. [11] P. Makreski, G. Jovanovski, A. Gajović, T. Biljan, D. Angelovski, R. Jaćimović, Journal of Molecular Structure. 2006, 788(1–3), 102–114.

189 Book of Abstracts P59

Raman Spectroscopy as useful tool for the gemmological certification and provenance determination of sapphires

Barone Germana,1* Bersani Danilo,2 Crupi Vincenza,3 Longo Francesca,3 Ugo Longobardo,4 Majolino Domenico,3 Mazzoleni Paolo,1 Simona Raneri,1 Venuti Valentina3

1 University of Catania, Department of Biological, Geological and Environmental Sciences, Catania, Italy, [email protected] 2 University of Parma, Physics and Earth Science Department, Parma 3 University of Messina, Department of Physics and Earth Sciences, Messina, Italy 4 Jeweller – Catania, Italy

In the last decade Raman spectroscopy was used for routine investigation in the characterization of gems,[1] as it offers many advantages for gemological purposes being nondestructive and noninvasive and granting short measurement times, low amount of material and no sample preparation. In this context, this work is focused on the spectroscopic characterization of different kinds of sapphires, by using handheld Raman instrumentation, in order to furnish gemological certification and to acquire information about the provenance of the gems. In particular, the aim of the present study is to distinguish between natural and synthetic sapphire and identify imitations gems. The Raman spectra are collected by means of a portable MiniRam™ series spectrometer (MADAtec) using a wavelength of 785 nm as excitation source, in the spectral range 175 – 3150cm-1. In order to perform further and deeper analysis on some selected samples, in particular for the characterization of the inclusions, a confocal JobinYvon Horiba Labram, equipped with the 632.8 nm and 473.1 nm excitation lines, is used. Figure 1. Raman spectra of The obtained data could improve the existing databases of gem spectra sapphire sample. recently built and wide available also in the Web.[2–5]

References [1] D. Bersani, P. P. Lottici, Anal. Bioanal. Chem. 2010, 397, 2631–2646. [2] RRUFF Project (2010) Department of Geosciences, University of Arizona, Tucson, USA. http://rruff.info/. Accessed 01 Mar 2013. [3] Minerals Raman Database (2010) Physics Department, University of Parma, Italy. http://www.fis.unipr.it/ phevix/ramandb.php. Accessed 01 Mar 2013. [4] Handbook of Minerals Raman Spectra (2010) Ecole normale supérieure de Lyon, Lyon. http://www.ens- lyon.fr/LST/Raman/index.php. Accessed 01 Mar 2013. [5] Raman spectra database, Dipartimento di Scienze della Terra, Università di Siena (2010). http://www.dst. unisi.it/geofluids/raman/spectrum_frame.htm. Accessed01 Mar 2013.

RAA 2013 190 P60

Authentication of ivory by means of 1064 nm Raman spectroscopy and X-ray fluorescence spectrometry

Maurizio Aceto,1* Alessandro Crivelli,2 Pietro Baraldi,3 Maurizio Bruni,2 Angelo Agostino,4 Gaia Fenoglio4

1 Dipartimento di Scienze e Innovazione Tecnologica (DISIT), Università degli Studi del Piemonte Orientale, Alessandria, Italy; Centro Interdisciplinare per lo Studio e la Conservazione dei Beni Culturali (CenISCo), Università degli Studi del Piemonte Orientale, Italy, +39 0131 360265, [email protected] 2 Nordtest s.r.l., Serravalle Scrivia (AL), Italy 3 Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, Modena, Italy 4 Dipartimento di Chimica, Università degli Studi di Torino, Torino, Italy; Nanostructured Interfaces and Surfaces Center of Excellence (NIS), Torino, Italy

Authentication of ivory has long been a problematic issue for archaeometry, as long as non-invasive analysis was concerned. It is hard to discriminate among ancient and modern ivory without using invasive and destructive measurements such as elemental content determination (carbon, nitrogen or fluorine content) or isotope ratio analysis. At the same time, ivories obtained from different animal species (elephant, hippopotamus, marine animals, etc.) can hardly be differentiated, since the composition keeps fairly constant among themselves. An analytical protocol for identification of the origin of ivories was proposed by Edwards et al. in several studies [1,2] in which the authors used FT- Raman spectroscopy. In the spectra obtained from ivory samples, the typical spectral features of both inorganic components, i.e. hydroxyapatite, and organic components, i.e. collagen, were identified and used by means of chemometric procedures in order to recognise the different species from which teeth and tusks ivory was produced. In a similar way, authors tried to individuate some spectral features useful to distinguish among modern and ancient ivory [3] but it was found that these features were highly dependent on the conservation history of the samples. An alternative approach was proposed with FT-IR spectrophotometry, still combined with chemometric procedures [4]. A major drawback of these procedures is that they were entirely based on measurements performed in laboratory. Most precious ivory artworks, however, cannot be moved from museums, due to their value and fragility, especially in cases where ancient items are concerned. In these cases portable instruments are needed, which should guarantee similar performances in the production of analytical information. In this study a combined Raman spectroscopy – X-ray fluorescence spectrometry is proposed to allow discrimination among ancient and modern ivory samples and among different animal species. Both techniques were used in portable version, in order to perform analyses in situ without need of moving samples. Raman spectroscopy was performed with the innovative Rigaku XantusTM-1064 spectrometer, equipped with 1064 nm laser source which showed to be the most suitable for analysis of ivories.

Acknowledgements This work has been financially supported by Nordtest s.r.l.

References [1] H. G. M. Edwards, D. W. Farwell, Spectrochim. Acta A. 1995, 51, 2073. [2] R. H. Brody, H. G. M. Edwards, A. M. Pollard, Anal. Chim. Acta. 2001, 427, 223. [3] D. A. Long, H. G. M. Edwards, D. W. Farwell, J. Raman Spectrosc. 2008, 39, 322. [4] C. Paris, S. Lecomte, C. Coupry, Spectrochim. Acta A. 2005, 62, 532.

191 Book of Abstracts OP33

Characterization of emeralds by micro-Raman spectroscopy

Danilo Bersani,1* Pier Paolo Lottici,1 Emma Salvioli-Mariani,1 Erica Lambruschi,1 Alessandro Francioli,1 Giulia Azzi,1 Germana Barone,2 Paolo Mazzoleni,2 Ugo Longobardo2

1 Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Parma, Parma, Italy, +39 0521905239, [email protected] 2 Dipartimento di Scienze Biologiche, Geologiche ed Ambientali, Università degli Studi di Catania, Catania, Italy

In recent years the use of Raman spectroscopy as a gemological tool has largely increased. In particular, in the conservation science field, the possibility to have a quick, non-destructive, contactless identification of a gem, maybe mounted on precious archaeological item, made this technique an invaluable procedure for gemologists and conservators. The results of the Raman analysis are not limited to the simple identification of a gem. In this work we show the large amount of information which is possible to obtain on one of the most important gems, emerald, the green variety of beryl. We studied by means of a standard micro-Raman spectrometer a large group of emeralds in different forms and of different origin: 15 faceted gems and a series of raw crystals (some of them still embedded in the host rock) coming from Val Vigezzo (Western Alps). Some fakes have been identified between the faceted gems (a garnet, a glass, a “quartz-beryl” sandwich). All the natural gems and crystals have been fully characterized from the vibrational point of view. In particular, the high frequency spectrum, in the OH-rich region, was used to estimate the amount of alkali ions present in the channels of the structure.[1] To quantify Be and Li, alkali ions in the channels such as Cs, Rb, K, Na, and other elements which better define the structure of beryl such as V, Cr, Mn, Fe analyses with LA-ICP-MS have been performed.

Figure 1. Raman spectra of two simulants found Figure 2. Raman spectra of an emerald coming from Val Vigezzo and of between the faceted gems and the characteristic Cr3+ the liquid and gas phases present in a fluid inclusion; the broad band of luminescence of the emerald excited at 473.1 nm. liquid water, the sharpest one of the channel water at ~3600 cm-1 and the peak of methane at 2915 cm-1 are clearly visible.

RAA 2013 192 OP33

In addition, solid inclusion were identified and used as a tool to differentiate the provenance of the emeralds. The shape and the position of the characteristic laser-induced luminescence of chromium ions was used to better define the origin of the gems.[2] Fluid inclusions present in the alpine crystals were studied; the identification of the phases and their concentration obtained by micro-Raman spectroscopy was completed by thermal analysis in order to made hypothesis on their genesis.

References [1] M. Łodziński, M. Sitarz, K. Stec., M. Kozanecki, Z. Fojud, S. Jurga. J. of Molecular Structure. 2005, 744– 747: 1005–1015. [2] I. Moroz, M. Roth, M. Boudeulle, G. J. Panczer. Raman Spectrosc. 2000, 31, 485.

193 Book of Abstracts OP34

Raman micro spectroscopy of inclusions in gemstones from a chalice made in 1732

Miha Jeršek,1* Sabina Kramar2

1 Slovenian Museum of Natural History, Ljubljana, Slovenia, [email protected] 2 Slovenian National Building and Civil Engineering Institute, Ljubljana, Slovenia

Sacral heritage of Slovenia is well documented and described.[1]Of special interest among the various chalices, monstrances and other vessels are the arte facts decorated with gems. The most outstanding in this respect is no doubt the baroque chalice made in 1732 with no less than 459 embedded gemstones.[2] The chalice, made of wrought and cast silver with engraved and chased decoration, and fully goldplated, is 30.2 cm high and measures 11.2 cm in diameter at the rim (Figure 1). It was manufactured in Graz, which in those times, during the Baroque period, was an important goldsmith'sandart centre. No data as to the chalice's manufacturer are at hand, except for the initials I. H. engraved and preserved in the chalice. In the interior of the chalice's foot, a plate with engraved inscription is attached, which reveals that this artefact, decorated with most precious gems, was commissioned by Sigismund Feliks, the Bishopof Ljubljana.[1] In 2001, all 459 gemstones on the baroque chalice were accurately inventoried, with their dimensions measuredand the as well as colour and type of gems determined.[1] On the basis of macroscopic observations, examination with a 10 x magnifying glasses, the conductivity and macroscopic analysis of the inclusions in the gems, the researchers determined 68 amethysts, 101 garnets, 93 rubies, 4 sapphires, 152 emeralds, 15 citrines, 24 diamond sand one sample of glass and dyed agate each. The jewels in the baroque chalice include numerous inclusions, some of which are recognisable already through a 10x magnifying glass, such as colourzoning in sapphires. With the aid of gemological microscope or stereo lens, other more or less characteristic inclusions can be detected as well, such as rutile needles, which give the distinctive appearance of silk, stress cracks around the zircon, liquid inclusions in the form of fingerprint, etc. Some solid inclusions, however, bear such a strong resemblance with each other that they simply can not be determined merely on the basis of observations of their morphology, orientation and size. This is the reason why we examined the gems embedded in the baroque chalice with Raman micro spectroscopy that enabled us to identiy the numerous solid inclusions in the majority of the stones, particularly in emeralds, garnets, rubies and sapphires. Identification of solid inclusions helps us not only to determine the types of gemstones, but primarily

Figure 1.Baroque chalice with 459 gemstones (left) with some detail (right). Photo: Ciril Mlinar

RAA 2013 194 OP34 to detect the sites and origin of gemstones.[3]In 1732, when the chalice was made, not all gemstone sites were known as yet. Diamonds were known to originate from India and Brazil, emeralds from Egypt, Habachtal in Austria, from the region of modern-day Afghanistan, Columbia and the Ural Mts. In those times, rubies were duglargely in SriLanka and Burma (present-day Myanmar), garnets in the Czech Republic, India and Africa, amethysts and citrines in some additional places as well. Through the analysis of solid inclusions by Raman microspectroscopy we managed to identify the types of solid inclusions in the jewels from the baroque chalice and thus to additionally confirm their origin in this most noble sacral vessel kept in Slovenia.

References [1] M. Simoniti, Zakladi slovenskih cerkva. Narodna galerija: Ljubljana, 1999, p. 199. [2] M. Jeršek, F. Šerbelj, B. Mirtič, Dragulji in motivi v kelihu iz leta 1732. Scopolia, 2001, 47, 42. [3] J. E. Gübelin, I. J. Koivula, Photoatlas of Inclusions in Gemstones, 3rd edition, Drückerei Wintherturdw AG: Zürich, 1997, p. 532.

195 Book of Abstracts OP35

Spectroscopic investigation: impurities in azurite as provenance markers

Mariafrancesca Aru,1 Lucia Burgio,2* Mike Rumsey3 1 Physics Department, University of Parma, Parma, Italy, [email protected] 2 Victoria and Albert Museum, London, UK, +44(0)2079422114, [email protected] 3 Department of Earth Sciences, Natural History Museum, London, UK, +44(0)2079426034, [email protected]

Background and objectives. As pigment microscopists know by experience, when one or more layers of azurite (a basic copper carbonate frequently used as a blue pigment in the past) are seen in a cross section, the blue particles are often intermixed with small amounts of impurities. Normally these are not related to other artists’ materials present nearby in the object, although occasional contamination should never be ruled out; the impurities present in the azurite-containing layers are typically green or orange-brown, although other colours can also be seen, and usually correspond to particles of malachite and iron oxides such as hematite and goethite,[1,2] which have traditionally been used as artists’ pigments in their own right since antiquity. This observation triggered a study aimed at finding out if those impurities were deliberate additions by the artist, or if they were present in the original mineral material. This study involved in the first instance the identification of the impurities (if any) present in high quality mineral specimens of azurite, i.e. specimens, which could have been chosen as a raw material for making the blue pigment in medieval and Renaissance time. Are different mines associated with specific impurities? Can these impurities, once they are found in azurite-based paint layers on museum objects, help identifying what mine the original source of azurite came from and therefore help reconstructing trade routes and mine usage over time? To find out, a collaborative pilot study was conducted between the Victoria and Albert Museum and the Natural History Museum, London. The latter provided 19 specimens of azurite from their historical collections, the provenance of which matched the azurite mines known in medieval Europe (Hungary, Germany, Austria, Spain etc.).

Method. The specimens were analysed by Raman microscopy in the first instance; this technique was chosen because it allows analysing minute impurities with minimal interference from surrounding materials. When possible, for each specimen both the matrix (i.e. the part of the host rock that the azurite crystals formed on, usually containing a high concentration of impurities) and apparently homogenous crystals or crystalline areas of azurite were analysed as they were, (i.e. as unbroken portions of mineral not yet reduced to powder). The crystalline azurite samples were subsequently ground to achieve a high-grade pigment powder, with grain size ranging from 1 to 15 _m. The powder thus obtained was then analysed in detail by Raman microscopy and a record was kept of all materials present as well as of any identification achieved. X-ray fluorescence and SEM-EDX analyses were occasionally carried out to support the Raman results.

Results. The study was undertaken with full awareness of its limitations at this stage: it is not statistically significant yet due to the relatively small number of specimens analysed; it is being assumed in first approximation that one or two samples can be taken as representative of a whole mine; the oldest specimens are likely to be from the end of the 18th century, therefore a lot ‘younger’ than any specimens mined in medieval times. The results obtained were therefore considered as preliminary, and further, more in-depth surveys will be conducted in the future. Nonetheless, several facts were ascertained:

RAA 2013 196 OP35

1) Goethite and hematite were found in almost every specimen analysed (13 and 14 out of 19, respectively), and malachite was detected in more than half of them; this is unsurprising as these minerals form and are stable under the same general conditions in nature that produce azurite. This confirmed that the presence of the three dominant material impurities in azurite-containing pigment layers can be ascribed to nature rather than artistic choice.

2) The red copper oxide cuprite, where present, is likely to be a remnant of the original copper-containing material(s) that actually lead to the production of the azurite from weathering/oxidation;

3) Calcite, quartz and two polymorphs of titanium dioxide, anatase and rutile, were also found fairly regularly. These minerals are examples of what geologists would term rock forming minerals and it would not be uncommon to find these specific minerals within the matrix of the specimens studied. As such it is hard to use these as markers for specific mines, although other rarer rock forming minerals or their relative proportions to each other in an azurite specimen may prove more distinctive.

4) Impurities such as jarosite, cerussite and rhodochrosite occur in a smaller number of specimens, but do not seem to be unique to one location alone.

5) The presence of cinnabar in all three Austrian specimens analysed is puzzling and needs to be investigated further to figure out if HgS is a possible marker (as there are mercury mines in the area) or represents a historical environmental contamination, possibly from before the specimens entered the NHM collections (as contamination within the V&A was ruled out).

Conclusion. The results of this pilot/preliminary study confirmed that the presence of abundant particles of pigment-type materials (such as malachite, hematite and goethite) within paint layers made of azurite is not due to a deliberate choice by the artist but is rather the consequence of the way azurite forms in nature and the minerals it is often associated with. Other materials, such as cuprite, calcite, quartz, anatase and rutile, which can occasionally be found as rare impurities in art objects painted with azurite, were found fairly regularly in the mineral specimens of azurite, and cannot be used as markers for provenance due to their ubiquity. Finally, further studies will be needed to find out if the materials that were identified less frequently (such as jarosite or cerussite), as well as their relative proportion, can help to narrow down the provenance of the original azurite mineral. A larger, more statistically significant sample set will be required to reach further conclusions relating azurite provenance to mineralogical impurity.

Acknowledgements The authors gratefully acknowledge the assistance of Prof. Danilo Bersani, University of Parma, in the interpretation of some of the Raman spectra collected during this study.

References [1] L. Burgio, R. J. H. Clark, R. R. Hark, PNAS. 2010, 107, 5726–5731. [2] L. Burgio, A. Cesaratto, A. Derbyshire, J. of Raman Spectrosc. 2012, 43, 1713–1721.

197 Book of Abstracts OP36

Implementation of scientific methods of fine art authentication into forensics procedures: the case study of “Bolko II Świdnicki” by J.J Knechtel

Barbara Łydżba-Kopczyńska,1 Marcin Ciba,2 Grzegorz Rusek1

1 University of Wroclaw, Faculty of Chemistry, Cultural Heritage Research Laboratory, Wroclaw, Poland, +48 71 3757379, [email protected] 2 Institute of Art History, Faculty of History, Jagiellonian University, Kraków, +48 12 663 1848

Over the last few years the Fine Art Market generated more than billion of dollars just in US, but there are suggestions that many pieces of arts that are being sold are of questionable authenticity. The number of fakes, forgeries and copies that appear on the art market in Poland in recent years is significantly growing, whereas the selection and standardization of procedures of verifying the authenticity of objects of art is not up to date, and seems to be losing the battle. Traditionally the decision is based on the opinion of art expert or art historian. However, the real statement of authenticity should include at least three levels of analysis: the confirmation of provenance, i.e. authenticity of documents supporting ownership, the verification of the artistic style of work by art expert and scientific analysis of the object using generally approved methods. The development of reliable document analysis was motivated by requirements of business contracts, useful tools in verification of authenticity of investigated masterpieces however, the subtle aspects of art style have been discussed by numerous experts over the years and are still far from validation. Therefore the introduction of scientific methods of analysis of object of art, based on examination of used materials and their transformations, may bring some.

The application of methodology used in forensic investigations, characterized by well defined procedures of sampling, instrumental methods of analysis and data handling, leads to consistent and reliable results, as could be seen in numerous cases of examinations of documents, drugs or explosives.

The scientific examination of piece of art incorporates the investigations of paintings materials like pigments and media, canvas, wooden support, nails etc. with the application of wide variety of noninvasive and non-destructive techniques. The discovery of the materials not consisting with the supposed time of the creation would suggest that analyzed object is not authentic. On the other hand, the consistency of all materials employed in the investigated piece of art with the time of creation does not necessarily prove the attribution of that object. In this situation the question that the forensic expert has to consider is how detailed the further analysis should be.

Our amassed experience gathered during recently accomplished authenticity and attribution investigations of the paintings, documents and cartographic objects[1–3] suggests that the implementation of forensic schemes into this type of investigations is beneficial. The schemes should cover the procedures of collecting, storing and protecting samples, as well as validation of applied analytical techniques. We consider the possibility of selecting the “authenticity/attribution markers” that would help experts to evaluate the levels of authenticity similarly to fingerprints analysis.

Joseph Jeremias Knechtl, one of the most famous painters of XVIII century, was nearly completely forgotten in following centuries. His artistic heritage is hardly known by art historians and his painting techniques and materials employed by the artist have not been investigated. Recently in Lower Silesia

RAA 2013 198 OP36 in Poland several painting attributed to J.J. Knechtl were discovered in private collection. The problem of authenticity of paintings preliminary attributed to J.J. Knechtl is attracting attention due to the rising interest in Silesian art and the growing art market in Poland.

The painting “Bolko II Świdnicki” of questioned attribution was subjected to comprehensive investigations based on noninvasive and nondestructive physicochemical analyses. Five paintings characteristic for each period of the painter creativity were selected for comparatives study. UV and IR photography was carried out to determine the state of the preservation of the paintings and to specify area for collections micro-samples. Both, unprocessed paint samples and paint cross-section were submitted to optical microscopy in order to characterize their stratigraphy. Application of ATR and Raman spectrometry, SEM-EDX point analysis and mapping delivered information about employed pigments and their distribution in different layers. HPLC analysis gave the complementary information about employed organic media.

The results of the investigations allowed to verify the attribution of the painting “Bolko II Świdnicki”. To test the hypothesis of attribution with reasonable significance the “authenticity/atribution markers” were selected. The markers, their number and relations among markers chosen to test the hypothesis will be disscussed.

References [1] B. Łydżba-Kopczyńska, E. Kendix, S. Prati, G. Sciutto, R. Mazzeo, 5th International Congress on the Application of Raman Spectroscopy in Art and Archaeology, Bilbao, Spain, 14–18 September, 2009, Book of abstracts: Juan Manuel Madariaga (ed.), Bilbao: Universidad del Pais Vasco, Servicio Editorial, 2009, p. 87. [2] M. Ciba, A. Kozieł, B. Łydżba-Kopczyńska, Obrazy Michaela Willmanna pod lupą, Muzeum Regionalne, Jawor, 2010, pp. 1–111. [3] B. Łydżba-Kopczyńska, L. Cartecchini, B. Doherty, Ch. Anselmi, D. Buti, Ch. Grazia, A. Romani, 2nd International Congress of Chemistry for Cultural Heritage (ChemCH), Istanbul, Turkey, 8–11 July, 2012, Turkish Chemical Society: Istanbul, 2012.

199 Book of Abstracts OP37

Raman analysis of multilayer automotive paints in forensic science: measurement variability and depth profile

Danny Lambert,1* Cyril Muehlethaler,1 Line Gueissaz,1 Geneviève Massonnet1

1 School of Criminal Justice, University of Lausanne, UNIL-Sorge Batochime, Lausanne-Dorigny, Switzerland, +41 (0)21 692 46 28, [email protected]

Paint analysis in forensic sciences is involved in diverse areas as the expertise of automotive paint), graffiti[1] household [2] or more generally, in the comparison of a trace evidence with a reference sample. [3] The criminalist’s objectives are both to identify the main components of a paint system and compare the composition of a trace and a reference sample, in order to infer on a potential common source. This follows a two-steps process: first a comparison based on the analytical results of the trace and reference sample is performed. This is then followed by an evaluative step to give information on the strength of the link potentially highlighted during the comparison process. Therefore several paints are examined. From the trace collection on a crime scene to the laboratory analysis, the paint samples will undergo various examinations, demanding different sample preparations. Comparison and identification of paint samples are achieved by different techniques, including microscopy, micro-spectrophotometry (MSP), elemental analysis (X-ray fluorescence (XRF) or scanning electron microscopy – energy dispersive X ray analysis (SEM-EDX)), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy and pyrolysis gas chromatography mass spectrometry (pyGCMS). Raman spectroscopy is appreciable as it requires few or no special sample preparation.[4,5] A recent study [6] demonstrates that Raman spectroscopy suffers from reproducibility problems which could be problematic in statistical treatments application (chemometrics). Actually, when attempting to develop chemometric treatments to classify and compare Raman spectra, it is imperative to minimize the variability among replicates of the same sample (defined as intra-variability). Therefore, the parameters that influence the distributions of the intra- and inter-variability (variations between measures from different reference samples) must be optimized. The ideal situation would be when the two distributions don’t overlap and when the intra- is a narrow distribution, in contrary of inter- which must be as broad as possible.[7] To reach this goal, the factors having an influence on the intra-variability must be identified in order to minimize them. When a multilayer paint sample is analysed, two types of analysis procedures are frequently encountered: cross-section of the sample (realized with a microtome) for the analysis of the layers and the so-called in situ analysis, which is realized without sample preparation. These two analysis procedures were evaluated in this research. In order to evaluate their influence as well as other analytical parameters on the intra-variability, a design of experiment (DoE) such as “fractional full factorial” was used. The following parameters were also considered: the paint type, laser spot size, objective magnification, microscopic slide type, number of accumulations and exposure time of the CCD. This statistical approach has the advantage of reducing the number of necessary experiments while allowing the visualization and the understanding of the impact of the tested factors on the measured response (in this research the variability).[8] The data collected were then analysed with chemometric tools such as principal component analysis (PCA) to observe the data distribution. The main outcome shows that analysis procedure has a more important effect than other tested parameters.

RAA 2013 200 OP37

To explore this result, surface characteristic (smooth or rough surface) of the sample were investigated. For multilayer samples with a clearcoat, its influence was also assessed through depth profile measurements. It was noted that the coloured layer can be measured through the clearcoat in order to avoid a preparation step. The findings of this study demonstrate the influence of sample preparation, on the variability of the measurement. All the conducted experiments show that the measurement variability on the colour layer is greater with a cross-section of the sample than in situ, even when analysing through a transparent medium (clearcoat). Thus, it is preferable to conduct in situ analysis of an automotive paint sample, when it is possible, rather than its cross-section to provide less measurement variability in the context of using a database. This survey helps to provide measuring guidelines to other laboratories in order to get the more reproducible spectra as possible. This study is part of a more general research on the comparability of Raman analyses between forensic laboratories.

References [1.] J. De Gelder, P. Vandenabeele, F. Govaert, L. Moens, J. of Raman Spectrosc. 2005, 36(11), 1059–1067. [2.] P. Buzzini, G. Massonnet, Science and Justice – J. of the Forensic Science Society. 2004, 44(3), 123–131. [3.] S. E. J. Bell, L. A. Fido, S. J. Speersand, W. J. Armstrong, Applied Spectroscopy. 2005, 59(1), 100–108. [4.] P. Buzzini, G. Massonnet, F. M. Sermier, J. of Raman Spectrosc. 2006, 37(9), 922–931. [5.] G. Ellis, M. Claybourn, S. E. Richards, Spectrochimica Acta Part A. 1990, 46(2), 227–241. [6.] R. S. Das, Y. K. Agrawal, Vibrational Spectroscopy. 2011, 57(2), 163–176. [7.] C. Muehlethaler, G. Massonnet, P. Esseiva. Forensic Science International. 2011, 209(1–3), 173–182. [8.] P. Esseiva, L. Dujourdy, F. Anglada, F. Taroni, P. Margot. Forensic Science International. 2003, 132(2), 139–152. [9.] D. R. Cox, N. Reid, The Theory of the Design of Experiments, Chapman and Hall/CRC, 2000.

201 Book of Abstracts Friday, September 6

RAA 2013 202 PL4

The Art of non-invasive in situ Raman spectroscopy: identification of chromate pigments on Van Gogh paintings

Costanza Miliani1

1 Istituto CNR di Scienze e Tecnologie Molecolari (ISTM) and SMAArt, Dipartimento di Chimica, Università degli Studi di Perugia, Perugia, Italy

Chrome yellows represent a class of pigments commonly used by painters of the late 19th-early 20th century such as V. Van Gogh. It has been found that upon exposure to sunlight, the both the chemical composition and the crystalline structure of the pigment critically influence the darkening behavior of this class of materials. Synchrotron X-ray based investigations by means of micro X-ray absorption near edge structure (µ-XANES), carried out on the artificially aged surface of a historic sulfate-rich

orthorhombic PbCr1-xSxO4 paint sample (Figure 1A) (Monico et al., 2011a) and on the sulfur-rich areas of the brown layer of two paint microsamples from the Van Gogh paintings Bank of the Seine and Field with flowers near Arles (both conserved at the Van Gogh Museum) (Monico et al., 2011b), allowed to effectively ascribed this darkening phenomenon to the reduction of the original Cr(VI) to Cr(III). The insights that chemical composition and the crystalline structure play a role in the alteration mechanism of these pigments have been successfully demonstrated by studying photochemically aged oil paint models made up of in-house synthesized lead chromate yellows (Monico et al., 2012a). Similarly to the historical pigment, a profound darkening and the formation of up to about 60% of Cr(III)-species in

the outer layer was observed only for those paints composed of sulfate-rich PbCr1-xSxO4 (x≥0.4) and an abundance of the orthorhombic phase higher than 30 wt % (Figure 1B).

Figure 1. Images of sulfate-orthorhombic rich PbCr1-xSxO4 (x~0.6-0.8) paints of (A) historic and (B) in-house synthesized materials before and after UVA-visible light exposure

If on the one hand investigations of model paint samples of either pure PbCrO4 or PbCr1-xSxO4 employing µ-XANES spectrometry made possible to attribute the alteration mechanism of the pigment to a reduction reaction, on the other Raman [Monico et al., 2012b] allowed to characterize chrome 2- yellow pigments depending on their chemical composition (in terms of SO4 abundance) and crystalline structure (Figure 2).

This preliminary spectroscopic study of paint model samples was very useful for the interpretation of the data have been collected from several embedded micro-paint samples taken from several paintings

by V. van Gogh and contemporaries, on which both chrome yellow forms (either as pure PbCrO4 or

PbCr1-xSxO4) were detected.

Similarly, recent in situ non invasive MOLAB Raman investigations on the painting Sunflower

203 Book of Abstracts PL4

(conserved at the Van Gogh Museum) allowed to map the distribution of pure chrome yellow in its co- precipitated forms, providing a possible explanation why only some chrome yellow-painted areas of the painting are prone to darkening. A detailed discussion of Raman spectra of chrome yellow pigments will be given and a comparison between the results collected from model paint samples and those collected from paintings by V.van Gogh and contemporaries will be illustrated highlighting potentialities and limitations of non invasive Raman spectroscopy.

References [1] L. Monico, G. Van der Snickt, K. Janssens, W. De Nolf, C. Miliani, J. Dik, M. Radepont, E. Hendriks, M. Geldof, M. Cotte, Anal. Chem. 2011a, 83(4), 1214–1223. [2] L. Monico, G. Van der Snickt, K. Janssens, W. De Nolf, C. Miliani, J. Dik, M. Radepont, E. Hendriks, M. Geldof, M. Cotte, Anal. Chem. 2011b, 83(4), 1224–1231. [3] L. Monico et al., Anal. Chem. 2012a: DOI: 10.1021/ac302158b. [4] L. Monico et al., Anal. Chem. 2012b: DOI: 10.1021/ac3021592.

Figure 2. Raman spectra acquired by means of the bench-top (left) and portable (right)

instrumentation from oil paint model samples of both pure lead chromate (S1mono, S1ortho)

and solid solutions of PbCr1-xSxO4 (S3A-S3D).

RAA 2013 204 OP38

Characterisation of a new mobile Raman spectrometer for in-situ analysis

Debbie Lauwers,1* Anna Garcia Hurtado,2 Vinka Tanevska,3 Luc Moens,1 Danillo Bersani,4 Peter Vandenabeele5

1 Department of Analytical Chemistry, Research Group Raman Spectroscopy, Ghent University, Ghent, Belgium; +32 (0)9 264 47 19, [email protected], [email protected] 2 Universitat de Barcelona, Barcelona, Spain 3 Institute of Chemistry, Faculty of Natural Sciences and Mathematics, University ‘Ss.Cyril & Methodius’, Skopje, Republic of Macedonia 4 Physics Department; University of Parma, Parma, Italy 5 Department of Archaeology, Archaeometry research group, Ghent University, Ghent, Belgium

Mobile Raman instrumentation is often used for in-situ characterisation and identification of inorganic and organic materials in art and archaeometry.[1] In the literature, one can find several publications on on-site, molecular examination of medieval wall paintings, museum objects, geo-biological samples, etc.[2–4] In all these cases, the definition of mobile Raman spectroscopy is somewhat arbitrary: different authors have different definitions. Colomban divides between mobile (instrument < 30 kg), ultramobile and hand-on (instrument or probehead < 2 kg).[5] Smith on the other hand, used mobile instrumentation as general term and made a distinction between portable (portable by 1 man) and transportable (transportable by 4 men) instrumentation.[6] In this work a new mobile instrument (cfr. defintion Colomban), EZRAMAN-I-DUAL Raman system (Enwave Optonics, Irvine CA, USA) is presented. The fiber-optic-based device is equipped with two type of lasers, a red diode laser (785 nm) and a green Nd:YAG laser (532 nm) and has three interchangeable lenses: a standard lens (STD), a long working distance lens (LWD) and a high numerical aperture lens (HiNA). The Raman spectrometer also consists of an adjustable power controller for each laser and has a CCD detector as detection system. When comparing this Raman instrument to other spectrometers, several advantages can be observed e.g. the possibility to use two lasers, to work on batteries, etc. The aim of this project was to characterise this Raman system. This characterisation was twofold: (i) Spectroscopic characterisation: develop a method for Raman shift calibration, check the stability of the lasers and instrument (on short and long term), define the laser output power corresponding to different reductions and the influence of grating change; (ii) Determination of characteristics needed for art analysis (working distance, positioning equipment, determine the LOD of pigments). Finally, the Raman spectrometer was also tested for its applicability for the in situ investigation of wall paintings. The spectroscopic characterisation of the instrument consisted of several aspects. The examination of the Raman shift calibration was performed with five reference products: sulphur, cyclohexane, 휀-caprolactone, acetonitrile/toluene (50:50) and polystyrene. The Raman bands of each standard (for both lasers and each lens) were compared with the reference Raman wavenumbers, presented in the literature. [7] The correlation indicated that a second calibration is necessary for lower wavenumbers, to obtain reliable results. Next to the calibration, the stability of the instrument, on short and long term, was investigated by analysing the fluctuation of the characteristic band position at 1001.4 cm-1 of polystyrene. The band positions over time denoted to be significantly constant which affirms the instrument to be stable on short and long term. Using the same method for the evaluation of the grating change (i.e. changing to the other laser), one can conclude that the instrument must be calibrated when interchanging the excitation source. Not only the stability of the instrument is an important feature, also the fluctuations of the laser wavelength

205 Book of Abstracts OP38 must be examined. By comparing the results of the recorded neon emission lines with the lines presented in the literature, it confirms both lasers to be stable with an average value of 784.9 nm and 531.8 nm for the red and the green laser, respectively.[8] As final aspect, to complete the characterisation, the relationship between the laser reduction and the corresponding laser output power at the sample was investigated. It was been found that no spectra could be recorded with a laser output power at the source lower than 33% for the 785 nm laser and 50% for the 532 nm. The second part of the characterisation contains the optimisation of the methodology needed for art analysis. One of the important factors for in situ Raman investigations of precious artefacts, is the working distance. By recording Raman spectra of polystyrene and determining the band intensity at 1001.4 cm-1, the optimal acquisition distance could be defined. Apart from the independency of the two laser excitation sources, each type of lens has a Figure 1. Preliminary result of the in situ set-up, developed in-house different optimal working distance: 7-8mm for the STD lens, < 1 for the LWD lens and 3mm for the HiNA lens. Next to the working distance, the positioning of the equipment is very important. Figure 1 shows a preliminary result of the set-up, developed in-house. After the characterisation of the new mobile Raman equipment, the efficacy of the instrument for pigment analysis was tested, giving satisfactory results which evidence the suitability of the EZRAMAN-I-DUAL instrument for pigment identification. As a general conclusion one can say that, the EZRAMAN-I-DUAL Raman system, provides good performance and spectra of good quality. The mobile spectrometer shows larger stability over short and long term independent of the used excitation source. Apart from the two laser excitation sources, this mobile instrument is equipped with three types of lenses (STD, LWD, HiNA) each with a different optimal working distance: 7-8mm for the STD lens, < 1 for the LWD lens and 3mm for the HiNA lens. Another important conclusion of this work is related to the laser power: it has been found that no spectra can be recorder, lower than 33% of the laser output power at the source for the 785nm laser and 50% for the 532nm.

Acknowledgements This research is financially supported by the European Commission, through the FP-7 MEMORI project ‘Measurement, Effect Assessment and Mitigation of Pollutant Impact on Movable Cultural Assets. Innovative Research for Market Transfer' (http://www.memori-project.eu/memori.html).

References [1] P. Vandenabeele, H. G. M. Edwards, L. Moens, Chem. Rev. 2007, 107, 675. [2] J. P. Vera, U. Boettger, R. Noetsel, F. Sanchez, D. Grunow, Planetary and Space Science. 2012, 74, 103–110. [3] M. Pérez-Alonso, K. Castro, J.M. Madariaga, Anal. Chim. A. 2006, 571, 121–128. [4] I. Reiche, S. Pages-Camagna, L. Lambacha, J. of Raman Spectrosc. 2004, 35, 719–725. [5] Ph. Colomban, J. Raman Spectrosc. 2012, 43, 1529–1535. [6] D. C. Smith, Spectrochim. Acta A. 2003, 59, 2353–2369. [7] M. R. McCreery, Raman spectroscopy for Chemical analysis, John Willey & Sons: New York, 2000. [8] H. Hamaguchi, Applied Spectroscopy reviews. 1988, 24, 137–174.

RAA 2013 206 OP39

On-site high-resolution Raman spectroscopy on minerals and pigments

Martin A. Ziemann1*

1 Universität Potsdam, Institut für Erd- und Umweltwissenschaften, Potsdam, Germany, +49 331 977-5876, [email protected]

Sample taking, touching or producing traces of analyses on valueable masterpieces and archeological and art objects are increasingly considered undesirable or prohibited. Raman spectroscopy can meet these demands, even if these objects cannot be transported to the lab and have to be studied on-site with a mobile Raman system. Sometimes however, objects are big and/or located at considerable height above the floor. Raman studies in the Grotto Hall of the New Palace, Park Sanssouci in Potsdam [1] we started with a mobile Raman equipment, which allowed measurements to only up to 1.80 m height. However, most of the 20.000 minerals, rocks and fossils in the Grotto Hall, that have to be identified are in bands located up to 4 m high.

A new mobile Raman system was designed for on-site measurements in positions in up to 5 m high. Thus, objects in any position in the Grotto Hall can be analysed, as well as pigments of wall paintings in chapels, museums etc. The lateral resolution and stability of the system is in the range of 5 to 10 µm, good enough for using a 50x ULWD micro-objective, thus allowing measurements on single pigment grains or microscopic inclusions in minerals.

References [1] M. A. Ziemann. J. of Raman Spectrosc. 2006, 37, 1019–1025.

207 Book of Abstracts OP40

Molecular Characterization and Technical Study of Historic Aircraft Windows and Head Gear Using Portable Raman Spectroscopy

Odile Madden,1,3* Kim Cullen Cobb,1 Alex M. Spencer1

1 Museum Conservation Institute, Smithsonian Institution, Suitland, MD, USA, [email protected] 2 National Air & Space Museum, Smithsonian Institution, Washington DC, USA

Introduction Early aviation design incorporated the most innovative plastics available at the time, and examples of these technologies are represented in the Smithsonian National Air and Space Museum (NASM) collection. Particularly interesting, and unexplored until now, is the co-evolution of transparent sheet plastics and the enclosure of cockpits in heavier-than-air aircraft of the 1920s and 1930s. A novel, non- invasive study of goggles, helmets, and airplane canopies in Smithsonian collections was undertaken. It is the first known large-scale technical survey of aviation plastics and leverages the world’s largest air and space collection as evidence of the materials and technologies used to create plastic objects in the early-20th century. The study relied heavily on portable, adjustable focal length, fiber optic Raman spectroscopy (AFL-FORS) and FT-Raman spectroscopy, techniques ideally suited to non-invasive characterization of polymers and 3-dimensional plastic objects. The Wright brothers’ first flew at Kitty Hawk in an open architecture aircraft. By 1910, pilots were given some protection from the slipstream and elements by covering the aircraft’s skeletal frame with fabric, leaving the top open for the pilot’s head and shoulders. These early cockpits were located behind the engine, and the pilot was pelted with wind, rain, ice, oil, and the occasional bird that happened into the propeller. All threatened the pilot’s ability to see and maneuver the plane. Goggles and small windshields were a first defense, provided they did not fail.[1,2] As flying became more common, ambitious pilots flew ever higher, faster, and year round,[3] which brought the need to enclose cockpits and still see out of them.[4] This period coincided with the development of shatterproof laminated safety glass and water-clear transparent plastic sheets that were lighter, more flexible, easier to shape, and less likely to shatter on impact.[5,6] Aviation soon was a target market for these products. Because the evolution of transparent window materials and plastic occurred on a similar trajectory, early aircraft - the production history of which is well known - are an opportunity to study developments in early transparent plastics. Written documentation of materials used tends to be from plastic manufacturers’ research and development reports, marketing materials, and advertisements. These offer valuable insight into what was available but may not coincide with what was used. The Smithsonian Museum Conservation Institute (MCI) and NASM teamed up to evaluate the potential of Raman spectroscopy to identify and characterize the plastics that actually were used.

Methods Ninety aviator goggles, flight helmets, and aircraft windows were analyzed by Raman and XRF spectroscopies. A portable BW Tek MiniRam II dispersive Raman spectrometer was the primary tool. It incorporates a 785 nm excitation laser, fiber optic probe, and CCD detection with 10 cm-1 spectral resolution. A custom adjustable focal length adapter was designed to facilitate analysis of laminated glass structures. Fluorescent artifacts, particularly colored or deteriorated plastics, were analyzed by Fourier-transform Raman spectroscopy using an enclosed, benchtop, research grade Thermo Scientific NXR module attached to a 6500 Fourier transform infrared spectrometer. The Raman module features

1064 nm excitation using a YVO4 laser and electronically cooled InGaAs detection. Spectral resolution was adjusted from 2-8 cm-1.

RAA 2013 208 OP40

Results and Conclusions Portable Raman spectroscopy has proven a useful tool for identification of synthetic polymers, plasticizers, and other compounds in plastic. It now is used routinely for sorting transparent and colorless plastics at Smithsonian and often can identify major components of intentionally colored or degraded plastics as well. We modified the portable spectrometer’s fiber optic probe to analyze laminated glass structures, a category of materials not anticipated when the grant was written. The addition of an adjustable focal length adapter allows us to focus the excitation laser on the polymer within the laminated glass sandwich. We propose that adjustable focal length fiber optic Raman spectroscopy (AFL-FORS) has great potential for analysis of transparent laminated structures, and other situations where the material of interest is located within a transparent substance. As expected, fluorescence interference was a challenge for many artifacts, particularly plastics that are colored or contain polarizing media. Better spectra were obtained for many with a NIR FT-Raman spectrometer, but the instrument is not portable and has a fixed sample compartment, which limits the range of artifacts that can be analyzed. This finding underscores the value in developing portable Raman spectrometers with NIR excitation. Using these tools and X-ray fluorescence spectrometry we constructed a timeline for the development of aviator eyewear and aircraft window materials through World War II. Open cockpit aircraft through the 1920s incorporated small windshields of glass or laminated glass. Sheets of cellulose nitrate also were used for windows where impact resistance and visibility were not vital. Pilots relied on goggles for eye protection, and laminated glass lenses were common. Plasticized cellulose nitrate was the laminating polymer from 1910 through the 1920s, when plasticized cellulose acetate began to supplant it in safety glass and other applications. In 1939 polyvinyl butyral (PVB) was introduced as an ideal safety glass laminating layer and still is used today. Transparent plastic sheets, particularly methyl methacrylate, were developed in around 1937 for windows and canopies and quickly were incorporated in American and German aircraft during World War II.

Acknowledgements This research was funded by the National Park Service and the National Center for Preservation Technology and Training. Its contents are solely the responsibility of the authors and do not necessarily represent the official position or polices of the National Park Service or the National Center for Preservation Technology and Training. The authors thank Gary Gordon of NASM and Don Williams, emeritus of MCI, for fabricating two iterations of the adjustable focal length adapter. Russ Lee (NASM) and Paula DePriest (MCI) offered valuable discussion.

References [1] Triplex Safety Glass A Vital Necessity. Flight, January 3, 1918, xxvii. [2] United States War Department, United States War Department Specifications for the Uniform of the United States Army Special Regulations No. 42, U.S. War Department: Washington, DC, 1917. [3] C. G. Sweeting, Hitler’s Personal Pilot: Life and Times of Hans Bauer, Potomac Books, Inc.: Dulles, VA, 2001. [4] L. F. E. Coombs, Control in the Sky: the Evolution and History of the Aircraft Cockpit, Pen and Sword Aviation: Barnsley, United Kindgom, 2005. [5] G. B. Watkins, W. Harkins, Industiral & Engineering Chemistry, 1933, 25, 1187–1192. [6] W. Davis, The Science News-Letter. 1941, 40, 314–315.

209 Book of Abstracts PL5

The Infrared and Raman Users Group Web-based Raman Spectral Database

Beth A. Price1*, Boris Pretzel,2* Suzanne Quillen Lomax,3* Marcello Picollo,4* Charles Davis,5 Andrew Lins,1 Haddon Dine,1 Gabriel Richards6

1 Philadelphia Museum of Art, US, +1 215 684 7552, [email protected] 2 Victoria and Albert Museum, London, UK, +44 207 9422116, [email protected] 3 National Gallery of Art, Scientific Research Department, DCL-SR, Washington DC, US, +1 202 842 6763, [email protected] 4 “Nello Carrara” Institute of Applied Physics – National Research Council, Sesto Fiorentino, Italy, +39 3666754973, [email protected] 5 The Dow Chemical Company, Philadelphia, PA, US, [email protected] 6 Endertech Corporation, Torrance, CA, US, [email protected]

Raman spectroscopy is a well-known powerful technique for the analysis of cultural heritage materials. The number of Raman systems installed in museum and academic laboratories has grown over the past decade. Despite this popularity, there remains a lack of readily-accessible, relevant, peer-reviewed, Raman reference data on known substances to serve as comparisons for samples taken from works of art and archaeological artifacts.

To help meet this need, the Infrared and Raman Users Group (IRUG) has partnered with the Philadelphia Museum of Art (PMA) on a project to create a Raman spectral database to be housed on the IRUG website at www.irug.org. This project is supported by a National Leadership Grant for Advancing Digital Resources awarded by the Institute of Museum and Library Services (IMLS) to the PMA in 2009.[1] It is the second database project to be undertaken by IRUG, which previously developed and distributed several infrared (IR) compilations, the latest containing over 2,100 peer-reviewed spectra of carbohydrates, minerals and pigments, oils and fats, natural and synthetic resins, and waxes. When completed, the Raman database is expected to become a similar fundamental resource for the international cultural heritage community.

The new Raman web-based database software allows users to create personal accounts for online submission, peer-review, editing, storage, and downloading of data (see Figure 1). As with the IRUG online IR database, spectra will be submitted in the non-proprietary raw JCAMP-DX (ASCII text) format, along with supporting information regarding the sample, sampling and data acquisition. After on-line peer review and quality assurance, spectra will be distributed in the IRUG JCAMP-DX format as discreet data records.[2] Additional project deliverables include: a software interface for public keyword and (digital) spectral searches of the database; a searchable Raman bibliography with peer-reviewed, downloadable, open-source PDF papers; and a glossary of chemical structures and terms.

IRUG has worked with Endertech, a Los Angeles based web design and software development company, to develop the Raman database and associated functionalities using MySQL® open-source database management system. Thus far, over 600 Raman spectra have been collected from various contributors worldwide to form the foundation of the database. Database beta testing and refinement currently are underway. The target date for launching the database is fall 2013. Individuals interested in participating should contact their respective IRUG Regional Chair: Beth Price, Americas; Marcello Picollo, Asia and

RAA 2013 210 PL5

Australia; Boris Pretzel, Europe and Africa; or the IRUG Raman Committee Chair, Suzanne Lomax.

Figure 1. Screenshot of redesigned IRUG website showing online Raman spectrum submission form and interactive spectrum accessed from a user personal account.

Acknowledgements This project is supported by the Institute of Museum and Library Services; National Center for Preservation Training & Technology; The Dow Chemical Company, Advanced Materials and Corporate Information Technology Divisions; Philadelphia Museum of Art; Victoria and Albert Museum; National Gallery of Art, Washington; and Institute of Applied Physics “Nello Carrara”, National Research Council. The authors also recognize Abigail Teller, Lauren Klein, Terra Huber, and Heather Brown for their important contributions.

References [1] The IMLS is the primary source of federal support in the United States for libraries and museums. Its mission is to create strong libraries and museums that connect people to information and ideas; to sustain heritage, culture, and knowledge; to enhance learning and innovation; and to support professional development. For more information, see http://www.imls.gov (accessed 19/08/2013). [2] JCAMP-DX (Joint Committee on Atomic and Molecular Physical Data Exchange) is a file specification. For full information on the IRUG JCAMP-DX protocol, see B. A. Price, B. Pretzel, S. Q. Lomax, C. Davis, J. Carlson, Revised JCAMP-DX Spectral File Format for Submissions to the Infrared & Raman Users Group (IRUG) Spectral Database, http://www.irug.org/ed2k/jcamp.asp (accessed 19/08/2013).

211 Book of Abstracts

Index Bensi 56 Claro 121 F Bergamonti 118 Clementi 95 A Bernard 27 Čobal Sedmak 132 Fazio 90 Bersani 35, 118, 152, 159, Coccato 40, 58, 188 Fdez- Ortiz de Vallejuelo Abagaro 145 166, 185, 190, 192, Coentro 154 60, 29, 140, 157 Abd El Hady 168, 170 205 Colomban 138, 155 Fenoglio 73, 191 Abdel-Motelib 170 Bešlagić 68 Comby-Zerbino 175 Ferreira 121 Aceto 73, 96, 191 Bleton 33 Conti 162 Ferrer 116 Acquafredda 155 Bongiorno 136 Coroado 125 Finkelstein 176 Adamo 166 Bouzas 112 Costantini 35, 152 Fontana 184 Adorni 185 Brai 184 Craenhals 66 Forray-Carlier 33 Agarwal 90 Brooker 70 Crivelli 73, 191 Francesca 190 Agostino 73, 191 Bruder 72 Cullen Cobb 208 Francioli 192 Agresti 164 Brunetti 88, 95 Freguglia 54 Aibéo 178 Bruni 73, 100, 191 D Freire 145 Aliatis 162, 185 Bucklow 26 Alloza-Izquierdo 157 Burgio 196 Daher 33, 48 G Almeida 184 Dararutana 187 Andaloro 164 C Davis 210 Gamberini 54 Anghelone 110 De Clercq 150 García 140 Antônio Cruz Souza 42 Caggiani 155 de Ferri 114 Gasparotto 52 Antunes 125 Caldeira 44 Defeyt 104 Gatta 166 Appolonia 86, 96 Campodonico 136, 173 De Laet 40 Gavrilenko 157 Aramendia 130, 138, 140 Campos Suñol 31, 123 de la Roja 112, 179 Georgova 178 Araújo de Faria 42, 64, 181 Candeias 44, 121, 125 de la Torre López 31, 123 Germana 190 Arteaga 179 Caneva 22 Delqué-Količ 175 Ghiara 136, 173 Aru 196 Carballo 183 Demšar 24 Giakoumaki 29, 157 Ayora-Cañada 31, 123 Careaga 64, 181 De Palma 173 Gomez-Nubla 138 Azkarate 140 Carlyle 38 De Torres 116 González-Vidal 134 Azzi 192 Carnasciali 173 De Vito 152 Graiff 118 Carvalho 125 Diana 96 Griesmar 51 B Casadio 86, 98 Dias 125 Gueissaz 200 Casoli 35 Díez 130 Gueli 184 Bacchini 152 Castellucci 102 Dine 210 Guglielmi 100 Backus 86 Castro 60, 92, 130, 138, 140 Dinis 184 Gui 106 Baldellou-Martínez 157 Castro, K. 29 Doherty 88 Gulmini 86, 96 Baonza 112, 179 Catarsi 185 Domene 31 Gutman 132 Baraldi 52, 54, 56, 73, 164, Cattersel 66 Domenico 190 191 Centeno 94 Domínguez-Vidal 31, 123 H Barone 192 Cerasoli 185 Barrero 179 Cerc Korošec 82 E Hernanz 157 Barrocas Dias 121 Chandler 75 Herremans 150 Barros 145 Chang 86 Echard 48 Hurtado 205 Basílio 184 Chércoles 112 Edwards 20 Basso 159 Cheshnovsky 176 Eixea 183 Becucci 102 Chillón 116 Elliott 26 Bellot-Gurlet 33, 48, 138, Ciba 198 Esteves 121 175 Cînta-Pînzaru 108 Ewa 50

213 Book of Abstracts I Lycke 40 Neira 140 Q Łydżba-Kopczyńska 198 Neri 90 Idone 86, 96 Nigro 152 Qian 75 Invernizzi 159 M Novik 95 Quiles 175 Ioffe 176 Quillen Lomax 210 Irazola 130 Madariaga 29, 46, 60, 130, O Isca 118 138, 140, 143, 157 R Iturregui 130 Madden 208 Oliveira 121, 125 Madrigal 175 Olszewska-Świetlik 50 Radi 170 J Maguregui 29, 46, 60, 157 Ossi 90 Raneri 190 Mahmoud 168 Otero 38 Reagan 80 Jembrih-Simbürger 110 Maier 64, 181 Reis 44 Jeršek 194 Malagodi 159 P Retko 27, 36, 82 Malekfar 62 Ricci 22, 102 K Mangone 155 Pacheco 181 Richards 210 Marte 64 Pagès-Camagna 51 Rizzo1 94 Kameranova 178 Martínez 157 Palamara 160 Roldan 94, 183 Kamitsos 160 Martinez-Arkarazo 29 Palles 160 Romani 95 Karampelas 188 Martini 136 Pallipurath 26 Ropret 27, 36, 82, 135 Kavkler 24, 128 Massonnet 162, 200 Paolantoni 95 Rosado 44 Knuutinen 29, 60 Mazzoleni 192 Paolo 190 Rosi 95 Kosec 135 Medeghini 152 Paolucci 56 Rossi 56 Kramar 132, 194 Melo 38, 92 Paris 33, 138, 175 Rubio Domene 123 Ménager 175 Pavlov 178 Rubio i Mora 157 L Menu 51 Pavlova 178 Ruiz-López 157 Mexia 121 Pellegrino 95 Ruiz-Moreno 116, 134 Laakso 60 Mignardi 152 Pelosi 52, 54, 164 Rumsey 196 Lambert 200 Miliani 88, 95, 203 Pérez-Pueyo 134 Rusek 198 Lambruschi 166, 192 Mirabaud 51 Pétrequin 188 Langlois 33 Mirambet 51 Piasetzky 176 S La Russa 159 Mirão 44 Piccardo 136 Lauwers 66, 150, 205 Mladenovič 132 Picollo 210 Sala 152 Le Hô 33, 51 Mladenovič 128, 132 Pitarch 29, 157 Salcedo 46 Leona 78, 80, 84, 92, 102 Moens 40, 58, 66, 104, 149, Platania 102 Salvioli-Mariani 192 Lesar Kikelj 68, 132 150, 205 Pogliani 164 Sambo 185 Lins 210 Möncke 160 Poli 162 San Andrés 112, 179 Lofrumento 102 Montagner 38 Ponterio 90 Sanches 38 Lombard 147 Montenero 114 Pontiroli 35 Santamaria 164 Lombardi 84, 102 Montoro 112, 179 Positano 162 Santoro 51 Londero 84 Morillas 46 Possenti 162 Saraiva 145 Longelin 125 Motahari 62 Pozzi 92, 98 Sawczak 119 Longobardo 190, 192 Muehlethaler 162, 200 Pozzi-Escot 181 Sayed 170 Lopes 92 Municchia 22 Predieri 118 Schade 123 López-Gil 116 Muralha 154 Pretzel 210 Schreiner 110 Lorenzi 114 Murcia-Mascaros 183 Price 210 Sedlmeier 70 Lottici 35, 114, 118, 152, 159, Muscillo 56 Prinsloo 147 Serrão 125 166, 185, 192 Proniewicz 50 Seruya 125 Lubin-Germain 51 N Sevilhano Puglieri 42

RAA 2013 214 Sgamellotti 88 Vekemans 150 Shah 86 Veneranda 130, 140 Shaus 176 Venuti 190 Silva 145, 154 Verhaeven 150 Simon 178 Viana 145 Skelton 26 Vieillescazes 175 Śliwiński 119 Vilarigues 38 Sober 176 Villaverde 183 Sodo 22 Viñas-Vallverdú 157 Soneira 134 Vincenza 190 Sousa-Filho 145 Vincze 150 Spencer 208 Stella 184 W Storme 136 Striova 162 Wachowiak 119 Strivay 104 Wadley 147 Špec 27, 36 Williams 70 Wondraczek 160 T Won-in 187 Wörle 188 Talebian 62 Wu 75 Tanevska 205 Taravillo 112, 179 Z Thomas 75 Thongkam 187 Zacharias 160 Tommasini 90 Zaffino 100 Toti 54 Zannini 52, 56 Trebolazabala 46 Ziemann 207 Troja 184 Żmuda-Trzebiatowska 119 Trusso 90 Turetta 152 Tzang 176 V

Vaiedelich 48 Valadas 121 Vandenabeele 40, 44, 58, 66, 104, 149, 150, 205 Vandenberghe 33 Van Duyne 86 Van Eester 66 Van Elslande 54 Van Groenland 66 Van Pevenage 40, 104, 150 Van Willingen 188 Vega Cañamares 80

215 Book of Abstracts

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