Conejo‑Barboza et al. Herit Sci (2020) 8:125 https://doi.org/10.1186/s40494-020-00470-4 RESEARCH ARTICLE Open Access Discovery of Vespasiano Bignami paintings at the National Theatre of Costa Rica through technical photography and UV–Vis spectroscopy Geraldine Conejo‑Barboza1,2,3, Eduardo Libby1,2, Carmen Marín4 and O. A. Herrera‑Sancho2,3,5,6* Abstract Establishing and understanding large format paintings are key to provide accurate information about the artist’s pal‑ ette and developing conservation strategies. Therefore, investigating the artworks of a population ofers insight into its culture, history and origins which reveals individual and collective identity through cultural heritage worldwide. Particularly, the ceiling of the Foyer at the National Theatre of Costa Rica (Central America) is decorated with three large format paintings from the nineteenth century made by the Italian painter Vespasiano Bignami. The paintings are known as La Poesía, La Música and La Danza (The Poetry, the Music and The Dance) and have undergone restorations in the past. However, their state of conservation is unknown and thus demands accurate scientifc examination in order to document their status and the extent of undocumented previous restoration work. To overcome those issues, we propose the application of a combination of non-invasive and in-situ techniques to carry out a qualitative assessment of the pigments and actual state of conservation. Here, we employed technical photography in the visible and near infrared regions, using panoramic stitching techniques in order to obtain high resolution images of the very large artworks. Several conservation problems were observed such as: detachment of pigments, cracks, stains, and sections with undocumented restorations. In the IR and False Colour Infrared images we observed a very conspicuous behav‑ iour of the red pigment used in the three paintings. Particular areas with the red pigment were fuorescent, and by means of ultraviolet fuorescence imaging we identifed the pigment as through its red-coral fuorescence as Madder Lake, by comparison to a historical pigments reference palette. Measurements in fve diferent red pigmented zones using UV–Vis spectroscopy in The Music show bands in the (550–650) nm region. A Lorentz Model nonlinear curve ft to the bands allowed us to correlate the fuorescent pigment in the paintings of Vespasiano Bignami with Madder Lake. Keywords: Madder lake, Technical photography, Fluorescent, Costa Rica, UV radiation, Spectroscopy Introduction by Iqbal and Hao “colour is an important and ubiquitous Nature has always amazed us by the colours it gener- part of our everyday life and ever since pre-historic times, ates, interpretation and use of colour have been part of colours, be they inorganic or organic, have had profound humankind since ancient times and until today, as said anthropological, psychological, aesthetic, functional and economic impact on society” [1]. Te pictorial materials used by artists throughout history are strongly linked to *Correspondence: [email protected] their material availability in nature, production technol- 2 Centro de Investigación en Ciencia e Ingeniería de Materiales (CICIMA), Universidad de Costa Rica, 2060 San Pedro, San José, Costa Rica ogy and trends of the respective epochs. For this reason, Full list of author information is available at the end of the article pigments can be decisive time indicators in many cases. © The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creat​iveco​ mmons​.org/licen​ses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creat​iveco​mmons​.org/publi​cdoma​in/ zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Conejo‑Barboza et al. Herit Sci (2020) 8:125 Page 2 of 10 Paintings are one of the most striking means that human fuorescent colour of Madder Lake. It is worth mention- beings have used to share our history, learning, personal ing that this pigment has been detected in many cultural beliefs and thoughts. Paintings refect the connection heritage objects, see [12, 14] and references therein for between the artist and its time, not only in the thematic further details. and stylistic aspects, but in the availability of art mate- Another important non-invasive, preliminary diagnos- rials such as pigments, binders and varnishes. Establish- tic technique is the use of technical photography to cre- ing and understanding these relations are key to provide ate high resolution images in the visible (Vis) and Near accurate information about the artist’s palette and devel- Infrared (IR) region of the electromagnetic spectrum. oping conservation strategies. Te photographs can be taken by using a digital cam- Artists historically have found inspiration in the col- era in which the sensor’s low-pass flter is removed and ours of Nature, and have made eforts to expand the col- replaced with a material transparent to UV, Vis together our range of inorganic pigments by using plant dyes [2]. with IR light. With images from the Vis and IR region, it A good example is the important Carmine Red (from is possible to create an infrared false color image (IRFC) cochineal insect) dye which was produced in Perú and by which to obtain information a preliminary qualitative México in Pre-Hispanic times and was used as a dye- identifcation of a pigment, such as in this case of Madder stuf. When combined with several mordants and salts, lake. An additional beneft of this technique is that is also it produces a variety of Lake pigments with diferent possible to discover previous restorations attempts. Te hues of red [3]. Tis red pigment, when found, can then images can be used for establishing a timeline and follow be used as a marker associated with the Spanish con- the state of conservation of the artwork [17]. quest, regarding the fact it was commercially available in Te aim of this study is to investigate qualitatively the Europe since the sixteenth century when was started to pictorial palette and the state of conservation of three be used in paintings [4, 5]. great nineteenth century paintings at the National Tea- To understand the history around an artist’s palette is tre of Costa Rica, known as La Poesía, La Música and La necessary to identify the pigments used in the artwork, Danza (Te Poetry, Te Music and Te Dance), made by this also afords valuable scientifc information for devel- Vespasiano Bignami, through the application of low-cost, oping adequate conservation strategies worldwide. A pig- non-invasive and in-situ techniques, such as UV–Vis ment with a very strong connection between time and spectroscopy and technical photography. An important industry is Madder Lake. It was used frst as dye for tex- consideration while examining these artworks, is that the tiles when it was manufactured in the early sixteenth cen- executive techniques traditionally used in Europe were tury B.C in Egypt [6], in book illustrations [6], in Rome not designed to withstand the efects of the climate and ceramics along with other archaeological objects [7–10], humidity of the tropics in Latin America. Deterioration and later on a pigment in paintings [6, 11, 12]. In spite of caused by these extreme tropical conditions is still largely its commercial success, the use of Madder Lake decayed unstudied, underscoring the importance of the present when Alizarin, one of its main components, started being research as a frst starting point towards establishing produced by synthetic means in 1869 by the chemists afordable multidisciplinary methodologies on cultural Graebe and Liebermann. Finally, it actually becomes the heritage worldwide. frst natural dye to be produced in the laboratory [13] In the next sections we present a brief history of Vespa- causing, as a consequence, a vigorous decrease in the use siano Bignami and his paintings, followed by the applica- of natural Madder Lake. tion of our experimental set up to the examination of the One of the most useful properties of Madder Lake is its paintings. We continue with our main results and discus- fuorescence under ultraviolet light (UV). Its fuorescence sion regarding the state of conservation and the identif- allows the identifcation of Madder Lake in paintings by cation of Madder lake. Lastly, we fnish with concluding using non-invasive methods, such as UV–Visible spec- remarks and detailed experimental methods and data. troscopy. Tere are interferences from the fuorescence of binding media [14, 15] additionally with low intensity bands of other components of the painting. Neverthe- Vespasiano Bignami less, an advantage is that this technique is non-invasive One of the most important aspects of studying the work and low-cost in comparison with chromatographic tech- of an artist is that art is always linked both to the artist’s niques and surface enhanced Raman spectroscopy personal history and also to the history of a country and (SERS) that require extraction of samples or more expen- its society: It is a refection of a specifc moment in time. sive equipment [16].