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Le nettoyage de peintures de chevalet est une operation de restauration courante qui comprend le decrassage, l’allegement ou le retrait de vernis oxydes, ainsi que le retrait de repeints indesirables. Dans certaines situations, les methodes traditionnelles utilisees par les restaurateurs (solubilisation ou retrait mecanique) ne suffisent pas pour aboutir a un nettoyage parfaitement controle et selectif. Pour pallier ces limitations, l’ablation laser UV (lasers a excimere, lasers Nd:YAG) est envisagee depuis les annees 1990, mais cette technique est loin d’etre une pratique courante. Par ailleurs, des systemes commerciaux operant dans l’infrarouge (IR) (Er:YAG) ont ete developpes pour etre utilises conjointement avec les methodes traditionnelles, mais cette approche n’a pas ete rigoureusement etudiee. Ce travail propose une reevaluation de l’utilisation de deux harmoniques UV du Nd:YAG (266 nm et 213 nm), ainsi qu’une etude systematique de l’utilisation du laser Er:YAG (2940 nm) pour le devernissage d’echantillons representatifs des peintures de chevalet. Le controle de l’epaisseur des couches et de l’allegement est assure par tomographie en coherence optique tandis que l’innocuite du traitement est evaluee par fluorescence induite par laser et par colorimetrie. La gestion de l’aspect de surface du vernis residuel est egalement examinee.

In consequence of the flooding of the Loing river in 2016, some of the storage areas for the Musee Girodet were submerged, with 3000 artworks affected. Following this, the painting Le Jeune Trioson...

In this work we have obtained terahertz images of hidden signatures that were located on the back side of the test-object’s canvas and covered by covered with a thick layer of brown paint. It was demonstrated that in the tomogram obtained at a frequency of 0.3-0.5 THz, the layers of paint applied on the other side of canvas are clearly distinguishable.

Terahertz (THz) radiation in the frequency range 0.1 - 10 THz began to be used for the analysis of artwork in 2006. Terahertz images of paintings require computer processing in order to optimize the process of detecting defects and their visualization. In this work, an algorithm for solving this problem is proposed in relation to the terahertz analysis of paintings. A program is written in Python that searches, group and highlight defects in an image. To work with images, the methods of the OpenCV library is used, designed to solve computer vision problems. They are used to binarize images and search the defect contours on them, as well as to isolate defects when visualizing the results. The grouping of defects is carried out by the method of agglomerative hierarchical clustering. Scientific analysis of the materials used in art items allows to determine the period in which they were created, how they were preserved over the centuries and how they were restored. As part of the study, in this work, a 3D-model of the crystal structure of the red pigment was created. For this, the terahertz spectrum of the pigment was modeled by the density functional method. To experimentally study the optical characteristics of the pigment, measurements are carried out on a TeraView-4000 instrument in transmission mode. The pigment is measured in powder and tableted form.

The IPERION HS project aims at establishing and operating an integrated activity for the establishment of a distributed pan-European research infrastructure on heritage science. Since 2016 heritage science is included in the ESFRI Roadmap through E-RIHS, the European Research Infrastructure on Heritage Science, evolving towards becoming an ERIC. Looking forward towards such time, IPERION HS will provide the pan-European heritage science community with a further level of integration and its rules and procedures are aimed at adaptation and improvement for future adoption under E-RIHS ERIC. As results from the working of a previous project of organizational nature (E-RIHS PP) the quality of a partner to the future ERIC will be established through an evaluation combining: i) a confirmation of the capacity to do things well; and ii) an assurance that such capacity is suitably managed to bear fruit in terms of results. For that purpose, the outcomes of actions taken by a partner will be evaluated as pertains e.g. their impact and the satisfaction of users. Known partners, those that have already co-operated within the group and are therefore recognized by their activities and the respective results, will be subjected to a simplified evaluation, namely attending to existing feedback from previous users, while new partners will be subjected to a complete evaluation. One of the main aims of quality monitoring under IPERION HS is to establish a background of data allowing to consider the partners of this project for a simplified evaluation scheme if, in the future, they apply to become partners to E-RIHS ERIC. A basic quality and evaluation system for the services rendered through the project and for its other outcomes is set by this task, based on flexibility and self-evaluation. The task also sets a group of Key Performance Indicators (KPIs) from which should evolve those to be used after the ERIC is established. KPIs will be aimed at forming a reliable picture of the evolution of the project in terms of conformity with set goals, progression of important factors and satisfaction of users in the broad sense of the word. Finally, the task will set ethical principles by which all those working within the Project and, later, under the E-RIHS brand are bound to abide. Those principles are expected to be consequent through procedures followed in all operations. The deliverable was developed from work done under E-RIHS PP and from the results of an ESFRI Working Group on the monitoring of research infrastructures performance published in December 2019. It includes contributions of IPERION HS WP 2, WP 3 and WP 4 on the survey of users' satisfaction and of WP 8 on the dissemination and communication KPIs.

This scientific study of color prints from chiaroscuro woodcuts is of particular interest and has not yet been carried out on Northern European prints. The aim of this work is to analyze the ink and paper chemical composition, and to define the sequence of printed layers in order to understand how the artists and their workshop achieved visual effects. The methodology, entirely non-invasive and non-destructive, involves the complementary use of imaging and spectroscopic techniques. Imaging techniques provide microscopic and macroscopic observations of the color prints. Together with infrared false color (IRFC) photography, they allow to make the first assumptions regarding the pigments and dyes used in the inks and their sequence of application. X-ray fluorescence (XRF) spectroscopy and fiber optics reflectance spectroscopy (FORS) in visible range enable to detect presence of paper treatments and to characterize pigments and, in some cases, dyes. The paper demonstrates the great potentiality and ability of the totally non-invasive imaging and spectroscopic techniques and shows, for the first time, the results obtained on Northern European chiaroscuro woodcuts produced during the 16th century.

Traditional “stack “manufacturing process (16–19th c.) of lead white pigment by lead corrosion is explored by exposing metal to acetic acid, carbon dioxide, dioxygen and water vapor. Global reaction scheme is revealed, along with stratification of corrosion products with CO2 gradient, leading to flakiness of corrosion layer. Kinetic and epitaxial features rule the polyphased structure, explaining hydrocerussite-rich compositions and absence of plumbonacrite in classical easel paintings. Microstructure of cerussite appears as a differentiation criterion between stack-made and industrial precipitation-synthesized lead whites. Particular conditions reported in ancient writings are tested and discussed to understand unusual processes.

Terahertz time-domain imaging (THz-TDI) and Spectral domain optical coherence tomography (SD-OCT) are two investigation methods capable of providing 3D datasets from which depth profiles, cross-sectional images, plan-type images and volume rendering of an object can be derived. These novel photonic technologies are extremely relevant to the field of heritage science, for which the comprehension of the stratigraphic structure of a cultural heritage object may help in the understanding of its manufacturing technology and state of preservation. Different imaging depths, fields of view and axial/lateral resolutions characterize the two imaging technologies, which thus provide different but complementary information of the same scanned object. In this study we show how the THz-TDI and SD-OCT scans performed on a fragment from the underside of an Egyptian coffin (Theban area, 21st/22nd Dynasties, Egyptian Antiquities department of the Louvre museum, Paris, France) gave precious insights on its full structure and stratigraphy.

The lead white pigment, composed of two main mineral phases cerussite PbCO3 and hydrocerussite 2PbCO3·Pb(OH)2, has been used in paintings since the Antiquity. The study of historical sources revealed that a large variety of lead white qualities were proposed, depending on the degree of sophistication of the pigment synthesis. Investigation of photoluminescence of the two constitutive mineral phases gave insight into the origin of the visible emission of these materials and emphasized the influence of structural defects on their photoluminescence properties. These effects were observed by combining emission and excitation spectra in two-dimensional representations. For each excitation wavelength, between 250 and 400 nm (4.9–3.1 eV), luminescence spectra were collected between 400 and 800 nm (3.1–1.5 eV). Two types of emission-excitation bands were identified: an emission excited in the optical bandgap of the compounds (about 5 eV), which depends on the constitutive phase (2.8 eV in cerussite and 2.1 eV in ...

Terahertz time-domain imaging (THz-TDI) and spectral-domain optical coherence tomography (SD-OCT) are two techniques capable of providing 3D datasets from which depth profiles and cross-sectional images of an object can be derived. They are novel photonics technologies of particular relevance to the field of heritage science, for which the comprehension of the stratigraphic structure of a cultural heritage object may help in the understanding of its artistic technology and state of preservation. The differences in imaging depth, field of view, and axial/lateral resolutions of the two imaging techniques provide different but complementary information of the same scene. Through the use of multimodal image fusion, the user will benefit from access to a detailed comparison of the information content of the two different datasets and images. To carry this out, we have developed a first data processing chain with the aim of representing THz-TDI and SD-OCT cross-sectional images in a unique image grid and space, in which the different datasets are dimensionally consistent.

Fifteen lead white-containing painting samples, about 1–3 μg in weight, from a selection of easel painting masterpieces of the Louvre and other French museums, dating from the Renaissance to the late 19th century, were investigated using synchrotron diffraction on the ESRF high resolution XRD beamline ID22. The Rietveld analysis revealed the nature of the pigments through the cerussite:hydrocerussite (PbCO3:Pb3(CO3)2(OH)2) ratios, the approximate dimensions of the crystallites and the presence of crystalline extenders. This first insight into a still widely unknown domain gives some hints, but also raises questions about the artists' preferences for selecting, preparing and post-treating white pigments. A significant increase of the crystallites size over five centuries also suggests an evolution of these processes.

Hyperspectral imaging has been used for pigment characterization on paintings for the last 10 years. It is a noninvasive technique, which mixes the power of spectrophotometry and that of imaging technologies. We have access to a visible and near-infrared hyperspectral camera, ranging from 400 to 1000 nm in 80–160 spectral bands. In order to treat the large amount of data that this imaging technique generates, one can use statistical tools such as principal component analysis (PCA). To conduct the characterization of pigments, researchers mostly use PCA, convex geometry algorithms and the comparison of resulting clusters to database spectra with a specific tolerance (like the Spectral Angle Mapper tool on the dedicated software ENVI). Our approach originates from false-color photography and aims at providing a simple tool to identify pigments thanks to imaging spectroscopy. It can be considered as a quick first analysis to see the principal pigments of a painting, before using a more complete multivariate statistical tool. We study pigment spectra, for each kind of hue (blue, green, red and yellow) to identify the wavelength maximizing spectral differences. The case of red pigments is most interesting because our methodology can discriminate the red pigments very well—even red lakes, which are always difficult to identify. As for the yellow and blue categories, it represents a good progress of IRFC photography for pigment discrimination. We apply our methodology to study the pigments on a painting by Eustache Le Sueur, a French painter of the seventeenth century. We compare the results to other noninvasive analysis like X-ray fluorescence and optical microscopy. Finally, we draw conclusions about the advantages and limits of the variable false-color image method using hyperspectral imaging.

The blanching of easel paintings can affect the varnish layer and also the paint layer with a blurring effect. The understanding of the physicochemical and optical phenomena involved in the whitening process remains an important challenge for the painting conservation. A set of ca. 50 microsamples from French, Flemish, and Italian blanched oil paintings, from sixteenth to nineteenth century, have been collected for in deep investigations. In parallel, the reproduction of the alteration was achieved by preparing some paint layers according to historical treatises and altering them in a climatic chamber in a humid environment or directly by immersing in ultrapure water. The observation of raw samples with a field-emission gun scanning electron microscope revealed for the first time that the altered layers have an unexpected highly porous structure with a pore size ranging from ca. 40 nm to 2 μm. The formation mechanism of these pores should mostly be physical as the supplementary analyses (Fourier transform infrared spectroscopy, gas chromatography–mass spectrometry) do not reveal any noticeable molecular modification. Considering the tiny size of the pores, the alteration can be explained by the Rayleigh or Mie light scattering.

International audience

« J’aime l’art d’aujourd’hui parce que j’aime avant tout la lumiere, et tous les hommes aiment avant tout la lumiere, ils ont invente le feu ». Apollinaire, conclusion du chapitre « Sur la peinture » de Meditations esthetiques, Figuiere & Cie, Paris, 1913.«La ligne (de la peinture) est la voix de la lumiere… Et quand la lumiere s’exprime pleinement tout se colore. La peinture est proprement un langage lumineux. » Apollinaire, Notes pour le bestiaire ou Le cortege d’Orphee, Delaplanche, Paris, 1911.« La couleur est un element vital comme l’eau et le feu. C’est incontestablement un besoin essentiel ». Fernand Leger, Fonctions de la peinture, preface Roger Garaudy, Gonthier, 1965 (re-ed. Folio Essais 309, 1996, augmentee en 2004).« Il pretait attention aux allees et venues de la lumiere sur la montagne et savait de mieux en mieux distinguer les differentes nuances de couleurs selon les heures du jour ou selon que les nuages se deplacaient plus ou moins vite sur le fond pâle du ciel. » Adalbert Stifter, L’homme sans posterite, p.109 (Phebus Libretto, 1844, trad. Georges-Andre Goldschmidt, 1978).

France is one of the countries involved in the future E-RIHS - European Research Infrastructure for Heritage Science. The research infrastructure dedicated to the study of materials of cultural and natural heritage will provide transnational access to state-of-the-art technologies (synchrotron, ion beams, lasers, portable methods, etc.) and scientific archives. E-RIHS addresses the experimental problems of knowledge and conservation of heritage materials (collections of art and natural museums, monuments, archaeological sites, archives, libraries, etc.). The cultural artefacts are characterized by complementary methods at multi-scales. The variety and the hybrid are specific of these artefacts and induce complex problems that are not expected in traditional Natural Science: paints, ceramics and glasses, metals, palaeontological specimens, lithic materials, graphic documents, etc. E-RIHS develops in that purpose transnational access to distributed platforms in many European countries. Five complementary accesses are in this way available: FIXLAB (access to fixed platforms for synchrotron, neutrons, ion beams, lasers, etc.), MOLAB (access to mobile examination and analytical methods to study the works in situ), ARCHLAB (access to scientific archives kept in the cultural institutions), DIGILAB (access to a digital infrastructure for the processing of quantitative data, implementing a policy on (re)use of data, choice of data formats, etc.) and finally EXPERTLAB (panels of experts for the implementation of collaborative and multidisciplinary projects for the study, the analysis and the conservation of heritage works).Thus E-RIHS is specifically involved in complex studies for the development of advanced high-resolution analytical and imaging tools. The privileged field of intervention of the infrastructure is that of the study of large corpora, collections and architectural ensembles. Based on previous I3 European program, and especially IPERION-CH program that support the creation of new mobile instrumentation, the French institutions are involved in the development of LIBS/LIF/RAMAN portable instrumentation. After a presentation of the challenge and the multiple advantages in building the European Infrastructure and of the French E-RIHS hub, the major interests of associating the three lasers based on analytical methods for a more global and precise characterization of the heritage objects taking into account their precious characters and their specific constraints. Lastly some preliminary results will be presented in order to give a first idea of the power of this analytical tool.

Blanching of easel oil paintings is a recurring alteration that can affect the varnish layer and also the paint layer itself, and strongly alter the visual appearance. Our examinations by field emission gun scanning electron microscopy (FEG-SEM) of altered and unaltered samples revealed the presence of spherical pores in the altered layers, with a pore size ranging from few nanometers to few micrometers. The aim of the present study is to corroborate that the visual appearance modification can be explained by light scattering theories (Mie or Rayleigh depending on the pore size of the considered layer). The four-flux model was used to resolve the radiative transfer equation (RTE) and model the light scattering in porous varnish layers as well as in porous green earth and raw umber oil paint layers. It enables to highlight that the pore size has an important impact on the visual appearance of the altered layer (color and opacity modification). The pore concentration and the thickness of the altered part affect, however, only the opacity. This work points out that the blanching of easel oil paintings is due to light scattering by the pores, which is an important result toward the proposal of adapted and durable future conservation treatments.

The work presented in this paper was performed at the Oriental Institute at the University of Chicago, on objects from their permanent collection: an ancient Egyptian bird mummy and three ancient Sumerian corroded copper-alloy objects. We used a portable, fiber-coupled terahertz (THz) time-domain spectroscopic imaging system, which allowed us to measure specimens in both transmission and reflection geometry, and present time- and frequency-based image modes. The results confirm earlier evidence that THz imaging can provide complementary information to that obtainable from X-ray computed tomography (XRCT) scans of mummies, giving better visualisation of low density regions. In addition, we demonstrated that THz imaging can distinguish mineralized layers in metal artifacts.

The modifications occurring to two well-established synthetic formulations (Mowilith DMC2®, Mowilith DM5®), upon accelerated degradation, were investigated. Degraded films of copolymers were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Differential Thermogravimetry (DTG), Atomic Force Microscopy (AFM) and colorimetry. The study highlighted the varied degradation of the two adhesives, which exhibit yellowing, alteration of their thermal and spectroscopic features and changes in their surface morphology and viscoelasticity. The main degradation route is characterized by the loss of acetyl groups, resulting in conjugated double bonds, as suggested by colorimetry and confirmed by FTIR. The loss of volatile organic acids represents a conservation issue when these adhesives are used for the lining of canvas paintings, since acidity promotes the hydrolysis of canvas cellulose. Rearrangement of the adhesives' molecular structure, and a competition between depolymerization and cross-linking were suggested by AFM and thermal analyses (changes in molecular weight are known to affect the solubility of copolymers and the possibility of their removal from works of art). The representativeness of the accelerated degradation protocol was positively assessed through comparison with naturally degraded adhesives.

International audience; Micro-samples collected on 28 major paintings by Old European Masters dating from the Middle Ages to the late 19th c. were analyzed using Synchrotron-based X-ray diffraction. Two complementary analytical configurations were used at beamlines ID22 (high-angle resolution) and ID21 (high lateral resolution), in order to highlight markers of the different grades of the lead white pigments (mixture of cerussite PbCO3 and hydrocerussite Pb3(CO3)2(OH)2). Rietveld analysis and crystalline phases mapping at the micro-scale revealed the composition and microstructure of the pigments, shedding light on the preparation recipes and pigment choices of the artists through History.

The first in situ micro-Raman spectroscopic study of prehistoric drawings found in the cave of Rouffignac-Saint-Cernin (Dordogne, France) was carried out. Rouffignac cave art, assigned to the upper Magdalenian Paleolithic period (13500–12000 bp), is constituted of more than 250 drawings and engraving including 158 mammoths. There are about a hundred drawings, all made of black pigments. Until now, destructive chemical analyses performed on one sample, as well as recent micro X-ray fluorescence (μ-XRF) in situ analyses have shown that the drawings contain manganese oxides. Because no carbon has yet been found, no direct dating of the drawings could be performed. This new study of the Rouffignac cave using non-destructive in situ micro-analyses aims at confirming or not the absence of carbon-based drawings and at understanding the apparent homogeneity of the parietal representations by the identification of the crystalline phases constituting the black pigments. The adaptability of portable equipment as well as the feasibility of in situ micro-Raman analyses in a cave environment was tested. The results obtained are compared with in situ XRF, and X-ray diffraction microanalysis is performed at the same time in the cave. We demonstrate that a portable Raman instrument is very useful to analyze non-destructively drawings in the following difficult conditions: high humidity, various wall geometries, and small amounts of material studied. These results show that the black manganese oxides romanechite and pyrolusite were used as pigments by prehistorical artists. Carbon and carotenoids have been found locally. Differences between the various figures are highlighted and hypotheses about the drawings production are proposed. Copyright © 2012 John Wiley & Sons, Ltd.

The authors present a review of the advances that have been made to establish terahertz applications in the cultural heritage conservation sector over the last several years. This includes material spectroscopy, 2D and 3D imaging and tomographic studies, using a broad range of terahertz sources demonstrating the breadth and application of this burgeoning community.

International audience; Terahertz Time Domain Imaging has been used in the last few years for the investigation of cultural heritage. In this article, the authors demonstrate the possibility to apply it for the investigation of clay artifacts. Tomographic images were obtained of a model in reflection, and an Egyptian vessel in transmission. © 2011 Springer-Verlag.

Resume La Garma est un site du Paleolithique superieur situe a une quinzaine de kilometres de Santander (Espagne), dans les Cantabres. La Galerie Inferieure que l’on atteint en descendant deux puits conserve des peintures parietales et de nombreux objets a meme le sol, objets sculptes, graves et peints, en os et en bois de renne, vestiges d’occupations et d’activites des Paleolithiques. L’analyse d’une cinquantaine de prelevements (37 rouges, 11 noirs, cinq jaunes, deux marrons, un violet) de la grotte de la Garma poursuit l’objectif d’etudier la chaine operatoire de l’activite picturale prehistorique, elle vise egalement a preciser les particularites de la caverne, en recherchant les differentes etapes de sa realisation, salle par salle. La presente etude donne une vision assez complexe et diversifiee de la decoration des parois : si quelques figures furent realisees rapidement, sans intention prealable, la plupart des representations furent, au contraire, le fruit d’une preparation elaboree de la matiere picturale avec l’emploi de pots de peinture specifiques.

Un laboratoire pour les musees ne decrit pas seulement une oeuvre a l’instant de son analyse : en adoptant une approche dynamique des faits techniques, les chercheurs parviennent a retrouver la « chaine operatoire » de l’artiste. Et l’optique, avec ses outils que sont l’analyse multispectrale, des rayons X aux ondes terahertz, l’imagerie 3D, la tomographie X et toutes les methodes spectrometriques non invasives, a un role essentiel a jouer. Suivez le guide !

Resume Pendant longtemps, la connaissance de l’art prehistorique des grottes ornees et des œuvres d’art mobilier a ete fondee sur l’etude stylistique des representations. Bien que des analyses chimiques fussent tentees par Henri Moissan, Prix Nobel de chimie, au tout debut du xx e siecle, des la reconnaissance de l’art parietal sur Font-de-Gaume et la Mouthe, les resultats etaient triviaux et venaient generalement confirmer la composition des pigments : oxydes de fer pour les rouges, oxydes de manganese pour les noirs ou, plus rarement, du charbon de bois. Ainsi, les archeologues edicterent des lois generales sur la composition de la matiere picturale et c’est la mise en valeur des procedes et le style des œuvres qui permirent a Andre Leroi-Gourhan d’etablir le mouvement general qui a ete suivi par cet art. Des analyses physicochimiques et des examens entrepris depuis les annees 1990 ont permis de preciser la chaine operatoire de cette activite humaine, de decrire les procedes techniques inventes et mis au point par les premiers artistes. Par les analyses chimiques de la matiere picturale, des outils, des couleurs, on cherche a determiner la nature dans le detail des pigments, leurs provenances, les conditions de leur mise en œuvre (tri, broyage, melanges…), les modes de depots, les differentes nuances de couleur. Le developpement des methodes de l’analyse chimique fut ainsi mis a profit pour ouvrir une nouvelle voie d’etude des manifestations artistiques laissees par les hommes du Paleolithique superieur. C’est l’enjeu de l’analyse des differentes manifestations de l’art prehistorique qui permettront a terme d’avoir une vision plus exacte de la strategie, de l’invention et de l’intention des cultures du Paleolithique superieur.

Prehistoric archeology has developed traceology, a discipline that consists in searching for traces of the way stone tools were used and employed by observing their surfaces. By extension and for all the works of the patrimony multiple and multi-scale traces will enable to understand the manufacturing techniques, the origin of the materials. In this way, general traceology aims at combining the traditional approach of art history, the history of pictures, with the powerful "operational chain" concept expounded by André Leroi-Gourhan., L'archéologie préhistorique a développé une discipline, la tracéologie qui consiste, en observant la surface des outils en pierre, à rechercher les traces de leur utilisation et de leur fonction. Par extension et pour l'ensemble des oeuvres du patrimoine, les traces multiples, à différentes échelles vont permettre de comprendre les techniques de réalisation, la provenance des matériaux. La tracéologie générale vise ainsi à conjuguer l'approche traditionnelle de l'histoire de l'art, l'histoire des images, avec le concept puissant de «chaîne-opératoire » énoncé par André Leroi-Gourhan., Menu Michel. La trace et l'empreinte, la mémoire des matériaux, pour une tracéologie générale. In: Les Cahiers du Musée des Confluences. Revue thématique Sciences et Sociétés du Musée des Confluences, tome 4, 2009. Les Traces. pp. 11-19.

Palaeolithic and modern reindeer antler were analysed using complementary techniques to evaluate the conservation state of bone material. X-ray diffraction, FT-IR spectroscopy, scanning electron microscopy (SEM‐EDX) and transmission electron microscopy (TEM‐ EDX) as well as proton induced X-ray and γ -ray emission (PIXE‐PIGE) at the particle accelerator AGLAE, C2RMF were applied. This study enabled us to define the chemical and structural features of ancient antler at the micro- and nanometre scale and compare them to those of other bone materials such as bone and ivory. Antler is richer in its organic fraction compared to bone and ivory. Its mineral fraction, carbonated hydroxylapatite, shows very specific crystal shapes at the nanometre scale. This specific property allowed us to recognize antler traces in pigment samples originating from rock art paintings in the Lascaux cave, Dordogne, southwestern France, Magdalenian period. Therefore, TEM‐EDX is the technique of choice for characterizing antler traces in complex mixtures. In the paint material of Lascaux, antler seems most likely to be a pollutant introduced either by stirring the pigments in water with a piece of antler or by carving antler artefacts next to the preparation of paint material. However, it could eventually be used as a marker of paintings that were created contemporaneously.

Bone materials record information on palaeodiets and palaeoenvironment, contained in their chemical and isotopic composition. Therefore, it is very important, while preserving these objects, to keep an open access to this information. In the present paper, we characterise the effects of consolidation treatments on the structure and chemical composition of archaeological reindeer antler at different hierarchical scales. X-ray diffraction, infra-red spectroscopy and microscopy, scanning and transmission electron microscopy coupled with an X-ray analysing system and proton-induced X-ray and γ-ray emission were used to reveal the state of preservation of reindeer antler and to evaluate the effectiveness of their consolidation treatments. These treatments are shown not to affect the chemical composition, but the crystallinity of the solid phase, as far as Palaeolithic material is concerned. In terms of penetration, the most efficient treatment, among those tested, seems to be the Rhodopas 15% single-bath treatment.

The feasibility of applying time-domain, terahertz spectroscopic imaging to the evaluation of underdrawings and paint layers embedded within wall paintings is demonstrated. Metallic and dielectric paint patterns and a graphite drawing are resolved through both paint and plaster overlayers using a pulsed-terahertz reflectometer and imaging system. We calculated the bulk refractive indices of four common pigments and used them to confirm color domains in a terahertz-beam spectral image of a painting.

Manganese oxihydroxide behaviour has been studied under heat treatment to understand the transformation mechanisms and subsequently to gain insights into the preparation procedures of black painting materials during the Palaeolithic period. These manganese oxihydroxides have been studied as a function of heat treatment by TEM, XRD, DTA and FTIR and XANES (Mn K-edge) spectroscopies. These materials have been used as black pigments during the Palaeolithic period to realise rock art paintings such as in Lascaux (Dordogne, France) and Gargas (Midi-Pyre´ne´ es, France). Specific morphological, chemical and structural criteria were determined to distinguish between natural and heat-treated pigments.

none 8 si To study degradation processes occurring on painting materials, the use of high-resolution micro-analytical techniques is highly requested since it provides a detailed identification and localisation of both the original and deteriorated ingredients. Among the various pigments recently studied, the characterisation of verdigris has received a major interest. This pigment has not a unique chemical formula, but its composition depends on the recipe employed for its manufacturing. Moreover, verdigris paints are not stable and are subject to a colour change from blue-green to green, which occurs in the first few months after the application. In this paper, we focused our attention on the use of ATR-FTIR mapping as a useful method to identify verdigris secondary products and pathways. Several mock-ups and real samples have been analysed, and the correlation among the detected compounds and their spatial location, obtained by the application of ATR-FTIR microscopy in mapping mode, allowed formulating some hypotheses on the degradation pattern of verdigris, which may feed the discussion on the transformation and stability of this pigment. From an analytical point of view, we showed how FTIR mapping approaches may be extremely useful both for the identification of compounds in complex matrix in which single spectra may limit the exhaustive characterisations due to bands overlapping and for the study of degradation pathways by taking into consideration the relative distribution of degradation products. Prati, S; Bonacini, I.; Sciutto, G.; Genty-Vincent, A.; Cotte, M.; Eveno, M.; Menu, M.; Mazzeo, R. Prati, S; Bonacini, I.; Sciutto, G.; Genty-Vincent, A.; Cotte, M.; Eveno, M.; Menu, M.; Mazzeo, R.

Human societies have never considered that it was imperative to preserve objects and artefacts as part of a heritage. In our present time, the destruction of goods is the engine of the economy; it allows production growth and social stability. However, simultaneously to the industrial revolution of the 19th century, it has become essential to collect and protect an increasing variety of traces from the past [1]. This includes not only objects kept in museums (remains of living species, artefacts, works of art, etc.), but also man-made structures (palaces, churches, industrial buildings, etc.) and even larger fractions of our environment as can be seen in the list of the UNESCO “world heritage.”

La scene naturaliste des « bisons adosses » de Lascaux, deja etudiee par les archeologues, pose la question de la conception d'une telle figure par les artistes magdaleniens. Afin de determiner les differents modes d'application, la nature des matieres picturales employees et leur mode de preparation, plusieurs prelevements ont ete etudies par microscopie electronique. Six prelevements, provenant de zones caracteristiques de ces deux bisons, nous permettent de reconstruire les gestes et de comprendre les intentions de ces hommes.

The material analysis of works of art aims to better understand the techniques of the ancient cultures and to preserve the cultural heritage for future generations. The analysis brings to light new and unique information for authentification, for conservation and more generally in the domain of history of artistic techniques. Until now, the methods were intensively developed and adapted to the specific, precious character of the works of art. Works of art are examined from the macro to the micro down to the nano scale thanks to TEM, atomic force microscopy, ion beam techniques, or synchrotron radiation spectrometries. Various examples will be developed in order to demonstrate the efficiency of the materials science methods for another entrance door to the cultural heritage artefacts.

Analysis of archeological materials aims to rediscover the know-how of prehistoric men by determining the nature of the painting matter, its preparation mode, and the geographic origin of its raw materials. The preparation mode of the painting matter of the paleolithic rock art apparently consisted of mixing, grinding, and also heat-treatment.