Microspectroscopic Analysis of Traditional Oil Paint Jaap van der Weerd The work described in this thesis was performed at AMOLF (FOM Institute for Atomic and Molecular Physics), Kruislaan 407, 1098 SJ, Amsterdam, The Netherlands. It is part of the research program of Priority Program MOLART (Molecular aspects of Ageing in Painted Works of Art) of the NWO (Nederlandse Organisatie voor Wetenschappelijk Onderzoek) and of the research program nr. 28 (Mass Spectrometry of Macromolecular Systems) of the FOM (Stichting voor Fundamenteel Onderzoek der Materie). © Jaap van der Weerd ISBN 90-801704-8-8 cover: balancing on the Art-Science interface. Results from infrared analysis of a sample from Falling Leaves (Les Alyscamps) by Vincent van Gogh. A processed version of this figure is included in this Thesis as Fig. 8.5. Microspectroscopic Analysis of Traditional Oil Paint ACADEMISCH PROEFSCHRIFT Ter verkrijging van de graad van doctor aan de Universiteit van Amsterdam op gezag van de recor magnificus Prof. mr. P.F. van der Heijden Ten overstaan van een door het college voor promoties ingestelde Commissie, in het openbaar te verdedigen in de Aula der Universiteit Op vrijdag 6 december 2002, te 10.00 uur door Jaap van der Weerd geboren te IJsselmuiden Promotiecommissie Promotores: Prof. dr. J.J. Boon Prof. dr. R.M.A. Heeren Co-promotor: Prof. dr. J.R.J. van Asperen de Boer Overige commissieleden: Prof. Dr. H. Schenk Prof. Dr. J.W. Verhoeven Prof. Dr. H.J. Bakker Dr. A. Burnstock Dr. T. Visser Faculteit der Natuurwetenschappen, Wiskunde en Informatica MOLART Reports MOLART - Molecular Aspects of Ageing of Painted Art - is a 5-year cooperative project be- tween art historians, restorers, analytical chemists and technical physicists funded by the Dutch Organisation for Scientific Research (NWO). Technical support and advice is given by Shell- SRTCA (Amsterdam), AKZO-NOBEL (Arnhem), Instituut Collectie Nederland (ICN, Amsterdam) and the Dutch art museums. The project was launched on 1 February 1995 and will end early 2003. The object of MOLART is to contribute to the development of a scientific framework for the conservation of painted art on the molecular level. The focus of MOLART is the determination of the present chemical and physical condition of works of art produced in the period from the 15th to the 20th century. Studies of historical paint manufacturing and workshop practice must give insight into the nature of the painters’ media and the painting technique used originally. Fundamental studies on varnishes, paint, and colorants are undertaken to understand the mo- lecular aspects of ageing since this is thought to be a main cause for the continued need to treat paintings. This thesis is the seventh in a series of MOLART reports that will summarise all research results obtained in the course of the project. Information about MOLART can be obtained from the project co-ordinator Prof. Dr. J.J. Boon, FOM-Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands. Previously issues of the MOLART series: 1. Molecular studies of fresh and aged triterpenoid varnishes, Gisela A. van der Doelen, 1999. ISBN 90- 801704-3-7 2. A mathematical study on craquelure and other mechanical damage in paintings, Petri de Willigen, 1999. ISBN 90-407-1946-2 3. Solvent extractable components of oil paint films, Kenneth R. Sutherland, 2001.ISBN 90-801704-4-5 4. Molecular changes in egg tempera paint dosimeters as tools to monitor the museum environment, Oscar F. van den Brink, 2001. ISBN 90-801704-6-1 5. Discoloration in renaissance and baroque oil paintings, Margriet van Eikema Hommes, 2002. 6. Analytical chemical studies on traditional linseed oil paints, Jorrit D.J. van den Berg, 2002. ISBN 90- 801704-7-X Publications This thesis is based on the following publications: Chapter 2 - Van der Weerd J, Van Veen MK, Heeren RMA and Boon JJ, The Identification of Pigments in Paint Cross-Sections by Reflection Visible Light Imaging Microspectroscopy (Vis- Imaging). Submitted to Analytical Chemistry. Chapter 3 - Van der Weerd J, Heeren RMA and Boon JJ, Evaluation of Preparation Methods and Infrared Techniques for the Infrared Spectroscopic Analysis of Traditional Paint. Submitted to Studies in Conservation. Chapter 4 - Van der Weerd J, Brammer H, Boon JJ and Heeren RMA, Fourier Transform Infra- red Microscopic Imaging of an Embedded Paint Cross-Section. Applied Spectroscopy 56(3): p. 275-283, 2002. Chapter 5 - Van der Weerd J, Van Loon A, Heeren RMA and Boon JJ, FTIR Studies of the Effect of Pigments in the Ageing of Oil. Submitted to Studies in Conservation. Chapter 6 - Van der Weerd J, Boon JJ, Geldof M, Heeren RMA and Noble P, Chemical Changes in Old Master Paintings: Dissolution, Metal Soap Formation and Remineralisation Processes in Lead Pigmented Paint Layers of 17th Century Paintings. Zeitschrift für Kunsttechnologie und Konservierung, 16(1): p. 35-51, 2002. Chapter 7 - Van der Weerd J, Van den Berg JDJ, Keune K, Zucker J and Boon JJ, Metal Carboxy- lates in the Grounds of 19th Century Preprimed Canvases used by F. Church. Submitted to the Journal of the American Institute of Conservation. Chapter 8 - Van der Weerd J, Geldof M, Struick van der Loeff L, Heeren RMA and Boon JJ, Zinc Soap Aggregate Formation in ‘Falling Leaves (Les Alyscamps)’ by Vincent Van Gogh. Submit- ted to Zeitschrift für Kunsttechnologie und Konservierung. Other publications: Van de Weert M, Van’t Hof R, Van der Weerd J, Heeren RMA, Posthuma G, Hennink WE and Crommelin DJA, Lysozyme Distribution and Conformation in a Biodegradable Polymer Matrix as Determined by Ftir Techniques. Journal of Controlled Release 68: p. 31-40, 2000. Wolters-Arts M, Van der Weerd L, Van Aelst AC, Van der Weerd J, Van As H and Mariani C, Water Conducting Properties of Lipids During Pollen Hydration. Plant, Cell and Enviromnent 25(4): p. 513-519. Van der Weerd J, Heeren RMA and Van Asperen de Boer JRJ, A European 640 X 486 Ptsi Camera for Infrared Reflectography. In: Le dessin Sous-jacent et la technologie dans la peinture. Colloque XIII, La Peinture et le Laboratoire. Procédés. Méthodologie. Applications, Leuven,1999 (Eds. Van Schoute R and Verougstraete H), p. 231-243. Uitgeverij Peeters. Heeren RMA, Van der Weerd J and Boon JJ, Ftir Imaging Spectroscopy for Organic Surface Analysis of Embedded Paint Cross-Sections. In: Fifth International Conference on Optics Within Life Sciences OWLS V, Crete, 1998 (Eds. Fotakis C, Papazoglou TG and Kalpouzos C), p. 179- 182. Springer. Boon JJ, Keune K, Van der Weerd J, Geldof M and Van Asperen de Boer JRJ, Imaging Microspectroscopic, Secondary Ion Mass Spectrometric and Electron Microscopic Studies on Discoloured and Partially Discoloured Smalt in Cross-Sections of 16th Century Paintings. Chimia 55(11): p. 952-960, 2001. JvdW had been involved in the acquisition of several Infrared Reflectograms, some of which have been published in the following references: Châtelet A, Jean Prévost Le Maître De Moulins, Monographies. Gallimard, Paris, 2001. Van den Brink P, Two Unknown Wings from a Tryptich by the Master of the Antwerp Adoration. ArtMatters 1: p. 6-20, 2002. Contents List of abbreviations 1. Imaging studies in paintings research ............................................................................... 1 1.1 Introduction ................................................................................................................................... 2 1.2 Physical structure of paintings ...................................................................................................... 2 1.3 Non-destructive analysis ............................................................................................................... 3 1.4 Sampling ........................................................................................................................................ 5 1.5 The imaging approach ................................................................................................................... 6 1.6 Scope of the thesis ......................................................................................................................... 8 2. The identification of pigments in paint cross-sections by reflection visible light imag- ing microspectroscopy (VIS-imaging)...................................................................................11 2.1 Introduction ................................................................................................................................. 12 2.2 Experimental ............................................................................................................................... 15 2.2.1 Sample origin and preparation .............................................................................................. 15 2.2.2 Hardware ............................................................................................................................... 15 2.2.3 Calibration ............................................................................................................................. 16 2.2.4 Data processing ..................................................................................................................... 16 2.3 Results and discussion ................................................................................................................. 17 2.3.1 System performance .............................................................................................................. 17 2.3.2 Imaging of azurite,