Raman analysis assessed by Fourier‐Transformed infrared and X‐ray fluorescence spectroscopies: a multi‐analytical approach of ancient chromolithographs from the 19th century

Abstract

A set of chromolithographs from the 19th century were analysed to identify the fillers and pigments used for their elaboration. Because of the delicacy of the chromolithographs, the research involved the use of Raman, Fourier‐transform infrared and energy dispersive X‐ray fluorescence spectroscopies for a complete characterization of the works on paper without removing any microsamples. Despite the high fluorescence of the samples when analyzed by Raman spectroscopy, in this paper, we demonstrated that ink spectra can be successfully enhanced by subtracting the spectra of the supporting background paper. The results of the study showed that, apparently, the lithographer used a limited range of common inorganic pigments from the 19th century (carbon black, chrome yellow, Prussian blue, red ochre, red lead and vermilion) together with organic pigments (indigo blue, gamboge and a red organic pigment). The study also found that despite the fact that during the 19th and early 20th century the use of mixtures of several pigments was a common practice, unusual admixtures were used for the preparation of some colours of the studied chromolithographs. Copyright © 2011 John Wiley & Sons, Ltd.

Identification of artistic materials in paintings and drawings by Raman spectroscopy: some challenges and future outlook

“…The complete identification of the colorants in most inks by Raman spectroscopy is sometimes challenging because their characteristic features often depend on the historic recipe used and/or on the natural source of the materials, and also because of interferences from the binding media and to aging. Important exceptions are the inks in modern marker pens used in contemporary art, the color lithographic inks, the ones colored with inorganic and/or with some natural organic pigments, such as indigo and aniline derivatives, and the inks containing some carbon‐based black pigments such as charcoal, ivory, or bone black …”

“…Particularly complex binding media were mixed with colorants in early lithographic inks that generally consist of a ‘varnish’ or carrying vehicle, containing processed linseed oil, rosin, and soap, and several additives or modifying agents, such as iron sulfate, lead acetate, litharge, Ceara rubber seed, sodium amyl sulfate, wax, mastic, copal, gum lac, shellac, tallow, soda ash, and turpentine. Despite the complex composition of the binders, the identification of the colorants in these inks by Raman spectroscopy is rarely precluded by fluorescence …”

“…The complete identification of the colorants in most inks by Raman spectroscopy is sometimes challenging because their characteristic features often depend on the historic recipe used and/or on the natural source of the materials, and also because of interferences from the binding media and to aging. Important exceptions are the inks in modern marker pens used in contemporary art, [88] the color lithographic inks, [89][90][91] the ones colored with inorganic and/ or with some natural organic pigments, such as indigo and aniline derivatives, and the inks containing some carbon-based black pigments such as charcoal, ivory, or bone black. [4,5,33,[92][93][94] Sodo et al used Raman spectroscopy to study a marker pen drawing made in the 1970s by Director Federico Fellini with the aim to determine the composition of the media and to get information on the deterioration process, and complemented the study by analyzing another drawing dating approximately to 2006 and samples made with new marker pens and with pens from the 1980s on paper, in the latter case by a combination of Raman spectroscopy and thin layer chromatography.…”

“…Despite the complex composition of the binders, the identification of the colorants in these inks by Raman spectroscopy is rarely precluded by fluorescence. [89][90][91] The precise identification of black pigments other than the ones mentioned above and of brown pigments used in inks, such as bistre and sepia, is difficult because of the heterogeneity of the materials and the fact that the compositions vary depending on the origin and on the manufacturing process. Bistre was usually prepared from wood soot collected close to the flame.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part VII

“…evaluated the intervention of a pair of Japanese folding screens from the early 17th century‐Namban genre belonging to the Museu Nacional Soares dos Reis (Oporto) by Raman spectroscopy using different wavelengths . Pitarch and co‐workers used Raman analysis together with FTIR and XRF spectroscopies in a multi‐analytical approach of ancient chromolithographs from the 19th century . Sakamoto, Tasumi, and co‐workers used Raman to study Japanese art objects by a portable Raman spectrometer using liquid crystal tunable filters .…”