Artwork appearances change over time due to aging. Smalt, a blue cobalt-tinted glass pigment, deteriorates over time in oil paintings causing significant and irreversible color changes in many artworks. Virtual simulations can hypothesis original appearances while it remains a challenge for smalt-containing paintings. A novel procedure integrates non-invasive imaging methods, X-ray absorption near-edge structure (XANES), and machine learning to simulate the original colors of a smalt-containing discolored paintings. Macro-X-ray fluorescence provided elemental distribution, reflectance imaging spectroscopy captured color spectra of pigments and XANES informed cobalt speciation in cross sections. Friedrich’s Abbey Among Oak Trees (1808-1810) containing smalt and artificially aged model systems were studied. Machine learning predicted the original hues based on XANES. The procedure allowed us to simulate the original, cooler and more vibrant colors of the painting. The innovative approach visualizes a possible original state of the smalt-containing artwork that can be adapted to other alteration phenomena.

L’étude scientifique de la Maestà avant et au cours de sa restauration a permis de préciser la palette comme la technique picturale de Cimabue à l’apogée de son art. Elle révèle une continuation de la tradition du xiiie siècle, mais aussi de nouveaux matériaux et procédés qui seront repris dans les années suivantes, en particulier par le jeune Giotto.

A painting from the Botticelli workshop has been studied after its recent discovery, with an innovative and noninvasive approach combining two- dimensional scanning macro-x-ray fluorescence imaging (MA-XRF) and a laboratory-based depth-resolved site-selective confocal micro-x-ray fluorescence (CXRF) device. These analyses were supported by measurements on cross-sections taken from the artwork using scanning electron microscopy coupled with an energy-dispersive x-ray system. The aims of this study are to confirm the painting's attribution and authentication, find characteristic markers and features, understand the artist's technique, materials used, and palette, and all of it while reducing sampling. The analyzing approach used combines imaging and site-selective techniques while avoiding, reducing and replacing sampling without compromising the results. Chemical maps of the painting were obtained by MA-XRF and enabled the identification of zones, colors, and chemical elements of interest alongside with a first assumption on the pigments used. Depth profiles were then performed in precise areas and colors using CXRF, allowing to evidence overlaying paint layers and obtain a more complete 3D vision of the painting. Contrasting the findings using this new methodology with the traditionally employed analysis process involving microsampling allowed us to determine the accuracy and veracity of our conclusions.

La recherche sur les pratiques picturales de Léonard de Vinci a bénéficié d’une nouvelle technique d’analyse non invasive devenue, par le biais des développements informatiques, une technique d’imagerie : la cartographie de fluorescence X. Les apports de cette technique seront illustrés à partir d’exemples nous informant sur la genèse des œuvres, la connaissance de la palette, l’analyse des motifs de la composition souvent devenus peu lisibles en raison du vieillissement de la matière, ainsi que la technique de réalisation des carnations. Nous tenterons ainsi d’esquisser une évolution des pratiques du maître.

Historical paintings with important iconographical changes represent an analytical challenge. Considering the case study of a fifteenth-century French painting studied during its restoration, the efficiency of a combined noninvasive approach of two-dimensional scanning macro-X-ray fluorescence imaging (MA-XRF) and a laboratory-based depth-resolved confocal micro-X-ray fluorescence (CXRF) is discussed. Large chemical maps of several elements were obtained by MA-XRF, enabling the identification of zones of interest representing changes in the painting composition. In these areas, depth profiles were measured with CXRF, allowing to evidence overlaying paint layers. The advantages of this technique are that it can give direct information on the stratigraphy of paint layers in a nondestructive way and can reduce the sampling needed, as well as increase the locations analyzed (in our study twenty-two depth-resolved scans). These results complement information obtained by scanning electron microscopy coupled with an energy-dispersive X-ray analyzing system (SEM–EDX) on three cross-sectional samples taken in the areas of interest. Additionally, the three cross sections of the painting were studied by CXRF lateral scans (y) in order to evaluate the efficiency of the CXRF analyses against SEM–EDX. The study shows the benefits of the combination of MA-XRF and CXRF for analyzing painting compositions, as such a high number of cross sections would have been impossible to sample. From an art-historical and conservation perspective, this combined study provides an understanding of the original painting’s paint sequence and its later retouches, helping to make informed conservation treatment decisions. Graphic Abstract

Analytical techniques such as macro X-ray fluorescence can capture dense multi-dimensional data that provides unique quantitative information at each point over the surface of a work of art. The processed outputs from scanning Macro-XRF are the elemental distribution maps that provide measurements of the abundance of the constituent elements at each point. The ability to visualize and correlate this data with other imaging modalities is an important step in understanding the material composition of a work of art. However, this data is often in a form which is hard to use directly or integrate with the results from other complementary analytical techniques. For example with the multi-dimensional data produced by reflectance imaging spectroscopy, or even with other standard scientific imaging modalities. As a result, Macro-XRF data is often handled and processed separately and the results only made accessible in the form of exported image renderings. In this paper, therefore, we will examine how Macro-XRF data can be processed into a practical and re-usable form that is compatible with other imaging modalities and how this data can be made more easily available through an integrated platform for multi-modal imaging. Open source software will be presented which implements this architecture, showing how quantitative Macro-XRF data can be visualized interactively through a web browser, integrated with other imaging modalities and how the underlying quantitative data can be made accessible and re-used using open formats and standard protocols.

The blue pigment smalt, a synthetic potash glass tinted with cobalt, was widely used between the sixteenth and the eighteenth centuries. As part of a study on the alteration of smalt and the reconstitution of its original color, the painting: Woman doing a Libation or Artemisia (Fontainebleau school, 1570) was examined in which the artist used smalt as a blue pigment, which is now degraded. Noninvasive imaging was performed using macro-2D X-ray fluorescence and reflectance imaging spectroscopy to get an overview of the artist's palette and its distribution. Samples prepared as cross sections were also analyzed by scanning electron microscopy coupled with energy dispersive spectroscopy, micro-X-ray absorption near-edge structure spectroscopy and synchrotron micro-X-ray diffraction imaging to determine the preservation state of the smalt as well as structural information on other pigments adjacent to smalt grains in individual paint layers, which could play a role in the degradation process. On the one hand, the study conducted on the alteration of smalt has shown that it is very weathered and mixed with hydrocerussite, which could be a factor that would facilitate the alteration. On the other hand, these analyses have made it possible to identify and locate the pigments used, which will be the basis for the virtual reconstruction of the color of the painting.

Amedeo Modigliani (1884–1920) is an artist highly valued by the public. However, his works have been little studied by natural scientists. The project “Modigliani and His Secrets” follows two closely correlated purposes: a better knowledge of the materiality of the works and a better understanding of the studio practice of the artist. The corpus (25 paintings and 3 sculptures, works belonging to French museums) covers the entire work of Modigliani in France from 1908 to 1920. The present article will focus on the beginning of Modigliani's artistic life through the analyses of two paintings dated from 1909 to 1913. The same multi‐analytical approach was implemented for each painting. It enables us to determine Modigliani's color palette, but also to unveil pentimenti and previous compositions. Complementary two‐dimensional imaging techniques operating in different spectral ranges (MA‐XRF, SWIR reflectance hyperspectral, X‐ray radiography…) were successful examining Modigliani's masterpieces to reveal the artistic know‐how and intentional strategy of the cursed and legendary artist.

In cultural heritage science, methodology development is constantly shifting because of the large variety of problems encountered during artefacts analysis. Generally, each case of study is treated individually and the analytical methodology cannot always be clearly reproducible. It may vary according to obviously the request, but also of sampling opportunities and nature of the objects studied. Issues of object geometry and representativeness are often raised in this field. The archaeometric study of the 21st Egyptian yellow coffins from the Louvre Museum have highlighted a global and recurrent scheme of the painting protocol. It has been observed that variations of this painting protocol can occur depending on the part of the coffin studied. These variations can result from the presence of a different number of layers, or even sometimes their total absence. It can also result from the layer thickness, material choices, or just the mode of their application. This article will present how the in situ non-invasive non-destructive methodology developed at the Centre de Recherche et de Restauration des Musées de France, has revealed, once applied to the wood panel E 20043, a painting protocol more complex than firstly originally believed.

The 21st Egyptian Dynasty marks a big change in funeral practices. Decorations are not anymore on walls, but on the coffin itself which acts as an entire grave. Egyptian Yellow Coffins, reserved to priests and priestesses of the Amon temple, are characteristics to this period and are only found in the Theban area. A multispectral and multiscale methodological protocol have been developed at the Centre de Recherche et de Restauration des Musees de France in the way to analyzed the painting materials used for this particular Egyptian production. A dozen of funerary sets, complete or not, of Yellow Coffins from the Egyptian Antiquity Department of the Louvre Museum, have been studied and permit to highlight a global scheme of the painting protocol. The goal of this study, which is taking part of the Vatican Coffin Project, is to get material identification to determine manufacturing process, and to try in fine to identify specific workshops. First results show that the painting protocol is more complex than we thought and actually can depend on the part of the coffin studied. The classic painting scheme includes a Muna layer on the wood support, a beige preparation layer, a white preparation layer which will receive the polychromy, comprising the yellow background, the red underdrawings and the painting layers; the final part is the varnishing of the object. Generally, variations of this scheme is about thickness of layers and materials used. It have also been noticed that differences of background treatment appear between the inner and the outer part of the case and also the higher and lower part of mummy boards and lids. Those variations can be attributed to workshops, fad or maybe temporal evolutions. But, one of the more complex part is the understanding of the painting protocol put in place for the inner part of external coffins. The corpus comprise only two, and both revealed a very particular stratigraphy. The first one, which is an entire coffin have been sampled and results showed the presence of yellow background applied around motives (so after the underdrawings and letting white areas in reserve), a local double layer of white preparation and orpiment (yellow arsenic sulphide) in suspension in the varnish layer. Because of the object geometry, it is currently not possible to proceed to non-invasive techniques on the inner part of coffins. However, the study of a decorated fragment from the Louvre collection, attributed to the inner bottom of an external yellow coffin, permits to go beyond this geometry problem by its plane surface. This case of study enabled us to perform XRF-mapping, which is not possible on a complete coffin. This technique allows with computer-generated images the spatial distribution (x,y) of the different elements (As, Cu, Ca etc.), assigned to the corresponding pigments, easily identifiable. Those data are compared to the UV and VIL imaging, which respectively provide spatial distribution (x,y) of the varnish and of the Egyptian Blue. VIL imaging also discriminate the position of blue beside of green, because both are copper pigments. Those analysis give us precious answers at a more representative scale, and confirm the complex protocol used in this particular part of the funerary set, showing that the As distribution (orpiment – As2S3) does not match with the yellow background or neither the varnish application. Rutherford Backscattering Spectroscopy (RBS) tests have been done with AGLAE (Accelerateur Grand Louvre d’Analyse Elementaire) on the panel and will be done on experiment samples which mimic the stratigraphy encountered. The RBS development methodology, never used with this kind of materials and problematic wants to determinate, in also a non-invasive way, the real position (z) of the arsenic in the stratigraphy, and understand this complex implementation. But for this purpose, it is necessary to corroborate non-invasive results with sample ones, the multiscale vision is essential.

An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The methodological protocol developed by the C2RMF have been for now, applied on a dozen of yellow coffins from 21st dynasty of the Egyptian Antiquity Department of the Louvre Museum. This first results on different pieces of funerary set give us a preliminary view of the production and raise some questions about the manufacturing process. Indeed, the extensive battery of examinations and analytical techniques permit to identify the wood employed for the structure of the coffins, which supports the complex stratigraphy of filling materials and polychromy. These materials themselves have been determined, both pigments and varnishes, and even binders in some specific cases. The wood identification shows a large use of Acacia, with Tamarix or Palm tree for the constitutive planks and the pegs of the coffins These objects present generally the same support preparation. Directly on the wood, different layers, in nature and compositions, are applied in the way to homogenize the surface and to receive the colors. The muna, a brown Egyptian silt rich in iron and manganese used for wall preparation mixed with vegetal fibers, is first encountered. Then, a white preparation is applied in one or sometimes two layers and contained principally calcium carbonates, or double carbonates, calcium and magnesium, which have been identified in particular cases. This coffin production is characteristic by the colour of it background which confers this particular aspect intended to imitate golden royal coffins. The study of the corpus permit us to highlight that the application of the yellow background is more complex than thought and actually depends on the part of the coffin studied. Difference of treatment have been seen between the inner and the outer part of the case and also the higher and lower part of mummy boards and lids. Concerning the polychromy we found that all the materials used are generally quite the same on the objects studied. We encountered iron yellow and red, orpiment, Egyptian blue and copper green. This last colour posed some problems of identification. Results revealed the presence of a synthetic copper green (bronze scraps traces) currently degraded which can be sintered pigments (close to Egyptian green) and organometallic pigments (copper-protein complex). The bright yellow varnish, also responsible to the golden appreciation, have been identified by GCMS campaign to be mastic resin, an exudate from Pistacia, and its application depends here also of the part of the funerary set studied. Orpiment grains can be encountered trapped in this last surface layer, or elsewhere in the stratigraphy, enhancing this shiny effect. We are trying to identify its real position in the stratigraphy for each coffin, in case it can be a workshop marker.

The painting L’Homme blessé by Gustave Courbet kept at the Musée d’Orsay in Paris has been recently studied by X-ray radiography, SEM–EDX observation of paint cross sections and confocal micro-X-ray fluorescence analyses (CXRF) at locations where the cross section samples were taken. This study allowed the establishment of the paint palette used by Courbet for the three paint compositions. Eight or more paint layers could be evidenced. In the view of the complexity of this painting, further analyses using two-dimensional scanning macro-X-ray fluorescence imaging (MA-XRF) providing chemical images corresponding to the superimposition of all detectable paint layers were employed. This method is combined with CXRF for depth-resolved paint layer analysis. Large elemental maps of Hg, Cu, As, Fe, Zn, Cr, Ba, Pb and Ca were obtained by MA-XRF on the painting and are discussed in combination with depth profiles obtained by CXRF on strategic points where three painting compositions overlap. The order of three successive compositions of this painting were determined in this study. This work also highlights the benefits of using complementary imaging methods to obtain a complete three-dimensional vision of the chemistry and stratigraphy of paintings.

Research performed on Early Neolithic ceramic assemblages from southwestern Bulgaria has revealed that several categories of pottery were used for the preparation of foodstuffs. One particular type of beige residue has been identified on the inner surface of ceramic vessels from several sites. Chemical analyses of mineral residues, combined with the stylistic characteristics of ceramic vessels, have shown the consumption of bone powder. This consumption, far from being anecdotal, raises several questions regarding the diet behaviour of the earliest Neolithic communities in the Balkans, which have obviously sought a complementary source of calcium. Would the dietary transition at the beginning of the Neolithic period correspond to a diet stress?

Since 2007, the research led on the Huaca Ventarrón site has allowed investigators to discover outstanding wall paintings. These murals are one of the oldest examples of this artistic expression in the Andean area and American continent (4000 BP). Analyses have given indications on the materials and techniques used by the first painters, ancestors of a long pictorial tradition.

Giotto (1266–1337) and his workshop realized c. 1315 the large Crucifix now in the Louvre Museum. The conservation of this masterpiece in 2010–2013 in the C2RMF studios gave the opportunity for a comprehensive investigation of the execution technique through a characterization of the paint layers. The first examinations revealed an original gilding and decoration surrounding the Christ which was repainted during the 19th C., raising the question of the original decoration appearance.