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Raman has long been established as a nondestructive and noninvasive technique that has found increasing application in the area of cultural heritage and the study of works of art. Here, we present a further application of Raman spectroscopy in the study of an oil painting belonging to the de Brécy Trust. In the work presented, Raman microscopy has been employed to spectroscopically study minute fragments of excised pigments from a small oil painting bearing the hallmarks of a study sketch by the famous English landscape artist John Constable. Raman spectra were collected from 18 discrete areas of the work, chosen due to their colour in order to potentially cover all of the pigments used in this work. Of the 18, six positive identifications were made, confirming that the painting contained pigments and minerals known to be favoured by the artist. Whilst the remaining 12 sample sites were complicated by the fluorescence effects observed from the applied varnish, this can be useful in providing evidence to support the application of the 'scumbling' technique known to be favoured by Constable. We have positively identified the pigments: ultramarine/lapis lazuli, lead white, red lead, Prussian blue, chrome yellow and ivory black. We have also identified amorphous carbon and gypsum. These positively identified pigments link into Constable's existing colour box and four palettes, providing evidence that could lead to the painting being attributed to Constable. [ABSTRACT FROM AUTHOR]

Noise filtering is considered a crucial step for the proper interpretation of Raman spectra. In this work, we present a new denoising procedure which enhances the Raman information whilst reducing unwanted contributions from the most frequent noise sources, i.e. the shot noise and the fluorescence's baseline. The procedure increases the signal-to-noise ratio whilst preserving simultaneously the shapes, positions and intensity ratios of the Raman bands. The method relies on cubic penalized spline fitting and mathematical morphology and requires no user input. We describe the details of this method and include a benchmark to study the performance of the presented approach compared with the most commonly used denoising techniques. The method has been successfully applied to improve the signal quality of Raman spectra from artistic pigments. The reliable results that were obtained make the methodology a useful tool to help the analyst in the interpretation of Raman spectra from pigments in artworks. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Raman spectroscopy combined with synchrotron radiation-based techniques and electron microprobe was used to study the yellow component of slips of marbled sigillata. Electron microprobe analysis emphasized on a significant corpus that the yellow component was well made from a titanium-rich clay preparation while X-ray absorption near edge structure investigation at Ti K-edge confirmed the massive presence of pseudobrookite (Fe2TiO5) in good agreement with previous study. Raman spectroscopy was correlated with X-ray absorption near edge structure results in order to extract the Raman spectra of pseudobrookite, which was compared with these ones of synthesized pseudobrookite powder reference. The investigation of a significant corpus (43 sherds) of marbled sigillata revealed that all samples exhibited similar Raman spectra in yellow zones attributable to the pseudobrookite structure. However, all spectra show the same features compared with the spectra of reference powder, that is, peak shifts and line broadenings, which could be related to Mg and/or Al substitutions in pseudobrookite crystals of marbled sigillata. The substitution plays a dual role in pseudobrookite structure: (1) stabilizes the structure through involving an increase of cationic disorder and (2) makes the color less dark and yellow, which could account for the nice yellow color of marbled sigillata. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

No abstract is available for this article. [ABSTRACT FROM AUTHOR]

Raman spectroscopy is one of the few non-destructive techniques capable of identifying pigments in art works. Raman spectra contain powerful information that can be used to identify unknown compounds and their chemical structures. However, the analysis of spectral data comes with some difficulties, and therefore the spectral interpretation is not straightforward. Sometimes, there are very little differences in the spectral data concerning to specific identification objectives, for instance, in polymorphic discrimination or in the discrimination of natural and synthetic forms of certain pigments. Moreover, this discrimination is often performed manually so that the process can be repetitive, subjective and particularly time-consuming. The result is an increasing motivation to automate the identification process involved in the classification of pigments in paint. In this paper, we propose a system to automatically classify the spectral data into specific and well-known classes, i.e. reference classes. The proposal is based on a combination of chemometric techniques, which provides a powerful way to achieve spectral separability so that it is possible to discriminate between very similar spectra in an automatic way. In this regard, a decision-making algorithm was specifically developed to select the corresponding reference class with no user input, which was successfully validated using simulated spectra. The implemented methodology was used to classify Raman spectra of pigments commonly present in artist's paints in experimental cases, providing reliable and consistent results. Therefore, the presented system can play a good auxiliary role in the analysts' endpoint classification. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The study deals with the characterization of pigments from the newly discovered wall painting at the Dominican Monastery in Ptuj (Slovenia) in order to acquire detailed information about the technology used, as well as to identify the deterioration products. The uncovered wall painting, depicting a vivid procession of riders, is dated to the late 14th century. Painting techniques and pigments were analysed by optical microscopy and Raman microspectroscopy. The optical microscope revealed that the wall painting was executed in a lime technique characteristic of the Central-European artistic expression. Several natural and synthetic inorganic pigments, such as azurite, red and yellow ochres, cinnabar, red lead, lead white, lime white, lead-tin yellow type I and carbon black were identified. Surprising identification of the type I of lead-tin yellow used already in the 14th century is of high importance, since, until now, it was considered that it appeared on the market only in the first half of the 15th century. Plattnerite was observed as a result of degradation of lead pigments. The use of expensive azurite and cinnabar could indicate a wealthy client. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The characterization of materials involved in painted works of art provides a better knowledge of artworks through the understanding of artistic and technological processes. In this study, some pieces selected from a large corpus of French Decorative Arts objects from 18th century museum collections were analyzed. These materials are complex system made of a multilayered colored background, covered with varnish layers. Colored or gilded ornaments are applied, representing different characters, flowers or landscapes, then varnished again. The aim of this study was to improve the painting and varnishing techniques knowledge in the Decorative Arts field during the 18th century. Vibrational spectroscopies, Raman, surface enhanced Raman spectroscopy (SERS) and infrared, were used to analyze some specific parts of these objects, especially organic materials such as lake pigments, binders and varnishes, and some of them were identified. For this purpose, a set of experimental setups and parameters were used according to the samples. The performed analyses were thus done using conventional FT-Raman at 1064 nm, SERS with a 458 nm excitation wavelength, infrared using a micro-ATR mode, and by defining for each technique and each analysed sample the best set of analytical parameters. The results obtained are all complementary and allowed us to completely identify and characterize multilayered paint systems as well as varnish compositions using specific data treatment methodology. This study is a description of the various possibilities that vibrational spectroscopies can provide when the right settings are employed, with a deeper look into the vibrational features using new data treatments. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Direct identification of pigments in mediaeval illuminated manuscripts was one of the first applications of Raman spectroscopy in art and archaeology. In previous in situ analysis of handwritings, the equipment was typically provided with a single excitation source. In this work, a portable Raman spectrometer (EZRAMAN-I-DUAL Raman system) is introduced to characterise the pigments used in an important illuminated mediaeval manuscript, De Civitate Dei (Library in Bruges, Ms.106). Characteristics important for these in situ measurements were discussed. We introduce a set-up that allows stable positioning of the equipment and point out the advantage of the availability of two lasers, which are part of the instrument. Good performance of the introduced Raman spectrometer, to allow pigment identification in a short time, is proved. Finally, pigments such as lead white (2PbCO3 · Pb(OH)2), lead-tin yellow type I (Pb2SnO4), malachite (Cu2CO3(OH)2), mosaic gold (SnS2), vermillion (HgS), carbon black (C), red lead (Pb3O4) and azurite (Cu3(CO3)2(OH)2) could be identified. These pigments were often used in mediaeval artworks and contribute to the enrichment of information of the materials used by the illuminator. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A pastel painting considered to have been painted by renowned Russian artist Natalia Goncharova in c. 1913 has been shown by Raman microscopy of the pigments to have been painted after 1952, with the identification of dioxazine violet. The implications of this discovery are discussed. This result highlights the need for reliable and perceptive dating procedures for valuation purposes. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper investigates, using only Raman spectroscopy, the spectral differences among the synthetic ultramarine blue (J. B. Guimet) and three natural ultramarine blues (lazurites) corresponding to three lapis lazulis from different geographical sources (Chile, Afghanistan and Siberia). The synthetic ultramarine blue used as reference pigment is the identified in an artwork created around 1917 by the Catalonian modernist painter Ramon Casas i Carbó. This synthetic pigment is compared with the three natural ultramarine blues and, in his turn, the latter are also compared each other. In order to quantify the spectral differences, a rigorous methodology based on the Euclidean distance between homologue spectral segments (or intervals) has been developed and presented here. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The development of solid-state chemistry at the end of the 19th century offered a variety of routes to colour a glass matrix. Eight enamelled glass objects made by Philippe-Joseph Brocard and two representative objects made by Emile Gallé have been analysed using a mobile Raman instrument at the Musée des arts décoratifs (Paris) in order to compare their colouration technology. White, blue, yellow, green, orange, red, brown and black pigments have been identified. If most of the pigment palette is common to both craftsmen and typical of the second half of the 19th century, innovative uses are recognized for Gallé (wollastonite as an opacifier, manganese oxides in black mixtures) and Brocard (specific black and grey, pigment mixture, shade modification by small addition of white and red pigments). This preliminary work confirms the potential of Raman spectroscopy, not as a simple analytical method but as a way to document the ancient technology of fine art objects and to discriminate between different genuine productions and/or copies. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Synthetic organic pigments are widely used in modern and contemporary works of art. They have been examined by a variety of techniques including spectroscopic methods such as Fourier transform infrared spectroscopy, Raman, and X-ray powder diffraction as well as chromatographic or mass spectrometric techniques such as pyrolysis-gas chromatography/mass spectrometry and laser desorption ionization mass spectrometry (LDI-MS). Often, a combination of techniques has been used to examine these pigments. This paper describes use of Raman spectroscopy to create a database of colorants including two pigments not previously reported, PO1 and PO2. Then, using Raman spectroscopy in combination with LDI-MS, samples from modern works of art by artists including Mark Rothko, Barnett Newman, and José de Rivera were examined in order to identify the pigments present. One finding was that Rothko used a variety of red pigments over the course of his career including PR11 which has not been previously reported in artwork, and PO2 found with its positional isomer PR1. Knowledge of the colorants serves to inform conservators about display and treatment decisions. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. [ABSTRACT FROM AUTHOR]