Maite Pérez-Alonso

Fourier transform infrared spectroscopy is a powerful analytical technique to study organic materials. However, in Cultural Heritage, since the sample under analysis is always a complicated matrix of several materials, data analysis performed through peak-by-peak comparisons of sample spectra with those of standard compounds is a tedious method that does not always provide good results. To overcome this problem, a chemometric model based on principal component analysis was developed to classify and identify organic binding media in artworks. The model allows the differentiation of five families of binders: drying oils, waxes, proteins, gums, and resins, taking into account the absorption bands in two characteristic spectral windows: C–H stretching and carbonyl band. This new methodology was applied in the characterization of binders in three kinds of artworks: papers of historical, archeological, and artistic value, easel paintings, and polychromed stone-based sculptures. Analysis of the binder in a wallpaper of the 19th century by means of FTIR spectroscopy and chemometrics

Non-destructive and non-invasive micro-Raman fibre optic and micro-XRF analyses were performed to study a wallpaper from the beginning of the 19th century. The complementarity of these two non-destructive techniques is shown in this work. The analysed artwork is considered one of the most beautiful wallpapers ever manufactured according to the catalogues and books; it is known as Chasse de Compiègne, manufactured by Jacquemart, Paris, in 1812. During the analysis, an unexpected pigment was detected by both analytical techniques: lead-tin yellow type II. This pigment was used until ca. 1750, when other yellow pigments replaced it, thus it is very difficult to find it in paintings afterwards. Together with this pigment, red lead, Prussian blue, brochantite, yellow iron oxide, calcium carbonate, vermilion, carbon black of animal origin (bone black), lead white, and raw and burnt sienna were also determined by combining the analytical information provided by both techniques. A possible degradation of brochantite to antlerite is also discussed.

During last years the application of chemical analysis to historical, artistic and archaeological specimens has gained more and more importance. The integration of scientific studies with information derived from stylistic or historic knowledge is really useful for the purposes of conservation, authentication, dating and attribution. Since the samples under examination are unique and irreplaceable the specimens must be submitted to non-destructive or at least microdestructive analysis. This work shows an overview of the state-of-the-art of vibrational spectroscopic techniques (mainly FTIR and Raman spectroscopies) as an analytical probe in artwork diagnosis, focusing on the need for specific spectra databases to perform accurate determinations. Some applications carried out by using both spectroscopic techniques will be presented.

Raman spectroscopy has been widely applied in the analysis of different types of artwork. This technique is sensitive, reliable, non-destructive and can be used in situ. However, there are few references in the literature regarding specific Raman spectra libraries for the field of artwork analysis. In this paper, the development of two on-line databases with Fourier transform Raman (FT-Raman; 1064 nm) and dispersive Raman (785 nm) spectra of materials used in fine art is presented; both are implemented in the e-vibrational spectroscopic databases of artists’ materials database (e-VISART). The database provides not only spectra, but also information about each pigment. It must be highlighted that for each pigment or material several spectra are available from different dealers. Some of the FT-Raman spectra available in the e-VISART database have not been published until now. Some examples in which the e-VISART database has been successfully used are presented.

In this work the analysis of a wallpaper from 1812 that was found in a palace in the Basque Country (Spain) is presented. The wallpaper represents a beautiful view of Paris and it is considered one of the most important wallpapers ever manufactured. The determination of the pigments present in the work was achieved using a Raman microprobe spectrometer, resulting in a completely non‐destructive analysis. All the colour shades observed in the wallpaper were manufactured with the pigments red, iron oxide yellow, iron oxide Prussian blue, Scheele's green, minium (Pb₃O₄), CaCO₃, lead white, carbon black, vermilion (HgS), raw sienna and burnt sienna. Copyright © 2004 John Wiley & Sons, Ltd.