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We thank the owner of the painting Mr. F. Fernandez Fábregas and the research group FQM-338 (University of Granada) for letting us use its facilities. We also thank Maria José Campos for the preparation of the cross-section samples, All the authors belong to the research team Unit of Non-Invasive Analytical Techniques Unit (University of Granada, Spain) funded by EQC2018-004952-P and A‐HUM‐164‐UGR18 Projects, currently active. All the authors read and approved the fnal manuscript. EM: Professor of Analytical Chemistry applied under Cultural heritage at the Department of Analytical chemistry of the University of Granada, Spain. The author contributed to the examination of the Transfguration of Christ, using photography, SEM–EDX, and performed the µRS and µATR-FTIR analyses; and contributed to the interpretation of the datasets, contextualization of data, and writing of the manuscript. RB: Full Professor of Analytical Chemistry at the Department of Analytical chemistry of the University of Granada, Spain. The author contributed to the examination of the painting, sampling, contextualization of the painting, elaboration of tables and fgures, contextualization of data, and participated in the interpretation of the datasets. The author read and approved the fnal manuscript. JDM-R: Professor of Mineralogy at the Department of Mineralogy and Petrology of the University of Granada, Spain. The author provided the interpretation of the mineralogical data. GCh: Professor of Mineralogy Applied under Cultural Herit‑ age at the Department of Earth Sciences of the University of Torino, Italy, Chief Scientist at the Getty Conservation Institute in Los Angeles, CA (director of the Science department for 11 years). The author works now as a freelance con‑ sultant in the feld of Conservation of Cultural heritage. The author read and approved the fnal manuscript. PS: Scientist at the SETI Institute and founder of eXaminart LLC. The author develops miniature X-ray analytical instruments for Space exploration ((e.g. the NASA CheMin XRD instrument inside the Curiosity Mars rover) and portable instruments dedicated to cultural heritage. The author contributed to the examination of the Transfguration of Christ, using pXRD. The author read and approved the fnal manuscript. JLV: Full Profes‑ sor of Analytical Chemistry at the Department of Analytical chemistry of the University of Granada, Spain. The author contributed to the Transfguration of Christ, using photography, SEM–EDX; contributed to the interpretation of the datasets, the contextualization and revision of data. All authors read and approved the fnal manuscript., The main objective of this study is to establish an appropriate method for the characterization of the pigments, materials and structure of the paint layers in a copy of the painting the Transfiguration of Christ by Raffaello Sanzio. A multi-technique approach that combines elemental, molecular and structural analyses and involves optical microscopy (OM), scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDX), mu-Attenuated Total Reflection-Fourier Transform InfraRed (mu ATR-FTIR), mu-Raman spectrometry (mu RS) and non-invasive portable diffractometer (pXRD) was used. Our results revealed that this copy of the Transfiguration was executed with a palette, which includes white lead (cerussite and hydrocerussite), lazurite from lapis lazuli pigment, red and yellow earths (goethite, hematite and lepidocrocite), lead tin yellow, cinnabar, red lake, smalt and bone black, and fillers such as calcite, baryte (an impurity associated to some pigments), and traces of colorless powdered glass. A secondary objective of this research was the application of non-invasive in situ pXRD measurements, which do not require painting sampling and helped to confirm some inconclusive results obtained with other techniques regarding the artist's palette. The results showed the crystalline nature of all the pigments identified, which were known from ancient times and available during the 16th and 17th. Lastly, the used of C-14 accelerator mass spectrometry determined that the canvas date was 1451-1633 AD (with a 95% confidence level). Although the main focus of the work was to improve the analytical methodology to better understand the artist's palette, our results will further help us to explore the authorship of the copy or the school that executed it., Non-Invasive Analytical Techniques Unit EQC2018-004952-P, Proyecto de investigación FEDER / Junta de Andalucía-Consejería de Economía y Conocimiento / A ‐ HUM ‐ 164 ‐ UGR18.

One of the analytical difficulties that may appear in the analytical process of the archaeological materials is related to the complexity of matrices. In this sense, the abundant content of lipids in archaeological degraded material makes the analysis of polyphenols much more problematic. In addition, phenolic compounds with a low-molecular weight might be present at trace level or even not be present in ancient artefacts. In this study, the advantages of gas chromatography–mass spectrometry in selected ion monitoring mode (GC–MS-SIM) for the analysis of wine biomarkers, tartaric and cinnamic acids, preserved in archaeological potsherd found in a votive deposit from the Iberian period in Granada (Spain) are presented. This will contribute to a greater understanding of the consumption of fermented beverages offered in votive rituals in Southern Spain during the Iberian period. To our knowledge, this is the first time that GC–MS-SIM technique is used to identify low concentrations of these polyphenolic acids in archaeological residues. In addition, the GC–MS-SCAN and gas chromatography–combustion-isotope ratio mass spectrometry (GC–C–IRMS) analysis revealed the presence of animal fats and vegetable oils mixed with wax and conifer resin preserved in the Iberian glasses. The correlation between organic compounds identified in the residues (short and odd-chain fatty acids (C9:0 to C12:0, C17:0 and C19:0), palmitic, stearic, azelaic, oleic, lignoceric and dehydroabietic acids and long-chain odd-numbered alkanes) and its possible origin are also discussed.

This paper seeks to reconstruct everyday human activities in a Bronze Age Argaric site in southeastern Spain. We used an integrated multi-analytical approach to study residues extracted from 5 ceramic pieces and 3 soil samples. The results of these analyses were complemented with archaeological interpretations to produce the first findings on domestic activities four millennia ago at the Penalosa settlement in Jaen, Spain. The bands observed in FTIR and ATR–FTIR spectra of the archaeological residues showed a peak assignment that confirmed the silicate components of the clay as raw material and the presence of organic matter. The amorphous organic materials were analyzed by GC–MS, HRMS and GC–C–IRMS, and the mineral residues by non-invasive portable X-ray fluorescence (pXRF). We identified α,ω-dicarboxylic and ω-(o-alkylphenyl) alkanoic acids produced by oxidative degradation of unsaturated fatty acids, as well as monocarboxylic acids, n-alkanes, diterpenoid acids, cholesterol, dyes and chemical grape markers. Assignments were based on lipid profile, fatty acid ratios and the δ13C values of C16:0 and C18:0. The results are consistent with the presence of tissues from ruminant (ovine or bovine) and non-ruminant (swine and equine) animals, vegetable oils, waxes, conifer resin and grape seeds. The presence of fish-based fats was suggested in one of the residues. Our evidence also suggests that grape juice or wine may have been consumed at this Bronze Age site. As far as we know this is the first investigation of the organic residues absorbed into an Argaric goblet used in a domestic situation.

A painting bearing the signature “Picasso” was investigated and its components – pigments and binders – were characterised using micro-Raman spectroscopy (mRS) combined with other analytical techniques such as Scanning Electron Microscopy with Energy Dispersive X-ray analysis (SEM/EDX), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Gas Chromatography-Mass Spectrometry (GC-MS). We identified the pigments in order to assess chronological inconsistency (anachronistic pigments) with the work of the Spanish artist Pablo Picasso (1881–1973) by means of in situ and cross-section analyses by mRS. Using mRS we identified the pigments ‘phthalocyanine blue’, ‘phthalocyanine green’, ‘pyrazolone orange’, ‘anatase’ and ‘rutile’ (titanium dioxide). These results were corroborated by SEM/EDX elemental analysis, which detected Ba, S and Zn among others, so prompting discussion about the use of ready-mixed house paints (Ripolin®). The ground layer was also investigated by mRS, which confirmed the use of rutile (titanium dioxide), calcite and phyllosilicates (Al, Fe). mRS on the white area identified the binding media as beeswax, the most important wax used in art. ATR-FTIR and GC-MS analysis support the presence of a wax and an oil–resin mixture as the binder, described in previous research as being used by Picasso. All the artist materials identified were widely used in art at the beginning of the twentieth century according to the available bibliography and are therefore consistent with the Picasso era. To the best of our knowledge this is the first attempt to investigate a painting related to Picasso using the combination of analytical techniques proposed here.

This work seeks to identify the slight changes in the characteristic CH stretching region (3100–2800 cm−1) of a protein-based binder and fatty acid esters from egg yolk, which may occur in complex paint samples due to the presence of particular pigments. To date, this protein region—where historic pigments do not show characteristic Raman bands—has not been used to identify possible interactions between painting materials, in spite of its potential due to the mentioned feature. This study is based on the investigation of pure egg yolk model samples and tempera model samples prepared by mixing this binder with some historic pigments (cinnabar, raw Sienna, lead white, gypsum, calcite, azurite, lapis lazuli and smalt) as binary samples. All samples were analyzed in this region by Raman microscopy (RM) coupled with principal component analysis (PCA) for three color groups (red, white and blue) separately. The results show relevant spectral changes in the CH stretching region of amino acids and polyunsaturated fatty acids esters of the egg yolk binder, particularly in the azurite, lead white and gypsum-based tempera samples. Lesser interactions were discerned in the tempera samples made with smalt, as well as shift in the region of polyunsaturated fatty acid esters of the egg yolk binder in the cinnabar and raw Sienna-based tempera paintings. No interactions were recognized between the egg yolk and the pigments calcite and lapis lazuli. The effectiveness of applying RM combined with PCA for identifying interaction processes between binders and pigments is demonstrated. Copyright © 2011 John Wiley & Sons, Ltd.

The effects of a UV-accelerated ageing test on model samples of azurite glue tempera, pure azurite and pure rabbit glue, all elaborated according to medieval recipes, were studied. The color changes and modifications in composition and texture for both pure and mixed samples are shown and discussed. Special attention is given to the physico-chemical interactions occurring when azurite and glue are combined. Ageing effects on the model samples after up to 3000 h of UV irradiation were periodically analyzed by scanning electron microscopy (SEM) with X-ray energy dispersive spectrometer (EDS) microanalysis, X-ray diffraction (XRD), reflectance spectrophotometry and Fourier-transform infrared spectroscopy (FT-IR). Once the ageing process ended, a chemometric study using principal component analysis (PCA) of the FT-IR data was carried out independently for every model sample and for all the azurite-laden samples. Loadings from the significant principal components were analyzed to identify the FT-IR frequency (cm −1 ) involved in the degradation process. PCA proved capable of identifying significant changes in pure glue samples. Also this work showed the lack of photochemical effects of UV irradiation on both pure azurite samples and those mixed with glue, in agreement with the SEM-EDS, XRD and colorimetrics results. Nevertheless PCA revealed that the azurite FT-IR spectral variability decreased in the presence of glue, being more affected by exposure to the IR region between 2100 cm −1 and 3600 cm −1 , where the azurite band is located. In addition, PCA managed to separate the azurite/glue mixture samples from pure azurite samples.

This work explores the application of principal component analysis (PCA) on first-derivative Raman spectra to investigate historical tempera paint model samples. Various paint model samples were prepared containing pure blue pigments (azurite, lapis lazuli and smalt), pure red pigments (cinnabar, minium and raw Sienna), pure white pigments (lead white, chalk and gypsum), pure egg yolk as binder and tempera model samples obtained by mixing each of the pigments with the binder, and further characterized by Raman spectroscopy. The corresponding Raman spectra were used to apply PCA in order to test whether spectral differences allowed discrimination of samples based on their composition. Multivariate analyses were performed separately on three data matrices, one for each color, namely, white, blue and red, corresponding to the model samples, and all containing the spectral data of the binder model sample. Different pretreatments, that is log and derivative spectra, were performed on the spectra since no pattern distributions were obtained when the original Raman spectra were analyzed. Nevertheless, the multivariate analysis of the original Raman spectra was able to track alterations of sensitive pigments due to laser interaction. Results showed the excellent ability of PCA, when applied to the derived Raman spectra, to discriminate model samples according to their differing compositions in the three groups of model samples tested. This is the first attempt to use this approach in the field of cultural heritage and demonstrates the potential benefits for identifying historical pigments and binders for purposes of conservation and restoration. Copyright © 2010 John Wiley & Sons, Ltd.

The Carrera del Darro is a street within the city of Granada, Spain, which is emblematic owing to the architectural value of its buildings, to its significance for the urban structure of the city and to the implications it has for the surroundings of the Alhambra. Our study concerns the chemical analysis of the mural paintings on four facades, corresponding to numbers 23, 25, 27 and 29 of the Carrera del Darro. From the analysis of the mortar, it may be concluded that the composition is very similar, though not identical, in the four paintings studied: a limestone mortar. Ochre, white, black and red were used for the decoration of the four facades; green pigment was also observed in the second decoration of no. 29. The results of the morphological examination and EDX microanalysis of the paint samples are shown. By means of the thermogravimetric analysis we established the existence of an organically derived compound. After the existence of an oleaginous binder had been discounted by gas chromatography/mass spectrometry (GC/MS) analysis, we continued with the extraction and determination of proteins by spectrophotometry analysis, detecting low levels of proteins in the paint on the four facades analysed. The study was completed by evaluating the influence on the deterioration of the paintings by the possible surface presence of salts (such as nitrates or chlorides) and organic compounds.

This work presents a preliminary study on the ageing process of proteinaceous binder materials used in painting under UV light. With this aim, two sets of model samples were prepared: samples prepared using a single protein material and complex samples prepared in a similar way to the sequence of layers in a real painting from lowest to highest complexity (protein, drying oils, pigment and varnish). The study focuses on acquiring information about the possible degradation process of proteinaceous binders due to ageing and how this process be affected by the presence of characteristic non-proteinaceous painting materials, such as lipids from linseed oil, terpenic compounds from varnish and inorganic pigments. Samples simulated the accelerated ageing process, as did the UV light exposition. The FT-IR spectra were recorded after 100, 500, 1000 and 1500 h of exposition. The study of the accelerated ageing process was performed by means of principal component analysis (PCA) using the FT-IR spectra obtained. Loadings from the significant principal components were analysed to find the FT-IR frequency (cm(-1)) involved in the degradation process. The study showed the lack of any relevant modification on the proteins in the single model samples. On the contrary, the complex model samples showed the ageing process. The accelerated ageing process can be explained by a principal component from PCA. The most affected IR region was 2900-3600 cm(-1), where the amide band was included.