Papers by Sandrine Pagès-camagna
La recherche menée depuis quinze ans au musée du Louvre sur les traitements de surface des figuri... more La recherche menée depuis quinze ans au musée du Louvre sur les traitements de surface des figurines grecques en terre cuite (peinture et dorure) évolue dorénavant vers l’étude des pratiques artisanales de la dorure (en grec chrysôsis). L’enquête qui suit a porté sur un ensemble d’une vingtaine de figurines, datées du IVe siècle av. J.-C. au IIe siècle après J.-C., fabriquées essentiellement en Grèce continentale (Attique, Béotie) et micrasiatique. Elle se propose, par l’examen des vestiges métalliques superficiels, de distinguer la part de travail qui revient au peintre et/ou au doreur : façonnées par la main et l’outil, ces traces restent en effet le meilleur témoignage du savoir-faire et du métier des artisans antiques. Ainsi leur relevé précis par vidéo-microscopie et l’analyse non invasive élémentaire et structurale de la feuille d’or, de l’assiette (« bol ») et de la préparation permet de retracer les différentes étapes nécessaires au travail de la dorure comme de souligner la haute qualification de ces artisans attentifs aux jeux d’ombre et de lumière, encore lisibles sur certaines des figurines. L’étude ainsi menée permet in fine de revisiter le statut de ces oeuvres.
Abstract :
A study of ancient surface treatments (painting and gilding) on Greek terracotta figurines has been carried out at the Louvre museum over the last 15 years. The research project is now focusing on the art of gilding (chrysôsis in Greek) and its ancient craftsmanship. Results presented here document some twenty objects of Attic, Beotian, South-Italy and Eastern Greece production (Myrina, Smyrna), dated to the IVth century B.C. – IInd century A.D.. Through a careful autopsy of the remaining physical evidence, the aim is to better understand and characterize the degree of technicality involved (did it require the specific expertise of a gilder’s ?). Archaeological traces provide indeed the best clues on the technè of ancient craftsmen. The study includes an in-depth examination of the figurines with a digital video-microscope, and non invasive elemental and structural analysis of the gold leaf, ground (« bolus ») and preparation layers. It discusses processes in the gilder’s work and allows for a better appreciation of the high quality of workmanship involved. Refined finishing treatments such as burnishing have been detected as well as « pictorial », light and shadow effects unknown so far. It concludes with reflections on the fonction of the objects.
Wax sculptures contain several materials from both organic and inorganic nature. These works of a... more Wax sculptures contain several materials from both organic and inorganic nature. These works of art are particularly fragile. Determining their chemical composition is thus of prime importance for their preservation. The identification of the recipes of waxy pastes used through time also provides valuable information in the field of art history.
New results on the local chemical environment of Cu 2+ in archaeological Egyptian blue and green ... more New results on the local chemical environment of Cu 2+ in archaeological Egyptian blue and green and also modern Egyptian green were obtained by x-ray absorption fine structure (XAFS) analysis. The information is essential for the understanding of the colouring mechanisms in both pigments. In a previous study, a clear physico-chemical characterisation of Egyptian blue and green was achieved using a complementary analytical approach with ancient and modern synthesized pigments. Electron microscopy (SEM-EDX and TEM), x-ray diffraction and micro-Raman and UV-visible spectroscopy were used to gain information about the conditions of the ancient Egyptian fabrication processes and permitted the clear distinction of both pigments. However, the exact colouring mechanisms could not be elucidated by these methods. Different Cu-bearing amorphous and crystalline phases were found in both pigments. These phases should be at the origin of the blue and turquoise colours. Using XAFS data at the Cu K-edge, new insights into the origin of the colouring mechanisms of both pigments could be obtained from the precision of the Cu speciation. In Egyptian blue, Cu 2+ is mainly allocated in a square-planar site in a crystalline cuprorivaite phase, whereas in Egyptian green, Cu 2+ is basically situated in a distorted octahedral site in an amorphous phase.
The use of chemical treatments by craftsmen to modify the surface aspect of metal objects is well... more The use of chemical treatments by craftsmen to modify the surface aspect of metal objects is well known especially since the Renaissance period. It is also known that the craftsmen in the Antiquity used to elaborate polychrome objects by juxtaposition of various kinds of alloys. But it is surprising that only one chemical patina recipe is attested for the antique period: the "black bronze" (Hmty-km in Egypt, Corinthium Aes in the Roman Empire). Moreover this black patina is complex and implies a quite high knowledge in chemistry. The question resulting from this observation is: why other voluntary patinas have not been reported on archaeological bronze artefacts? Different reasons may be given: the black patina was indeed the only used, the other patinas have been degraded by corrosion, they have not been detected until now, or the object surface has been too much cleaned during the postexcavation story of the pieces.
The concurrence and complementarities of obtained images under various wavelengths and the elemen... more The concurrence and complementarities of obtained images under various wavelengths and the elemental and structural analyses provided by XRF and XRD, using portable noninvasive systems, have allowed obtaining accurate data about the employed pictorial technique in two Egyptian wall paintings dating from the New Kingdom. Thus, compounds such as Egyptian blue, Egyptian green, goethite, jarosite, hematite, calcite, anhydrite or huntite have been detected in the paintings. The performance of the measurements by the different techniques and its contribution to the knowledge of the materials are discussed. They notably give a track on the origin of arsenic compounds, unexpectedly detected in some decors. PACS: 61.05.cp, 78.70.En; 42.30.Va; 07.85.Jy
The blue pigment smalt, a potash silicate glass coloured with cobalt, was commonly used between t... more The blue pigment smalt, a potash silicate glass coloured with cobalt, was commonly used between the sixteenth and eighteenth centuries. The composition is complex and can vary considerably depending on the manufacturing process and the elements that are present in the raw materials in addition to the essential silica, potassium and cobalt. It also often degrades through leaching of potassium, leading to a change in cobalt coordination from tetrahedral to octahedral, and a loss of the blue colour. In this study smalt pigment (both well preserved and altered) in samples from paintings in French collections (mainly Musée du Louvre) and in the National Gallery, London, as well as modern references of more simple composition, was analysed by the complementary vibrational techniques Raman micro-spectroscopy and synchrotron Fourier transform infrared micro-spectroscopy. Comparison of the spectra with those from modern smalt, together with spectral decomposition and correlation with quantitative SEM-EDX elemental analysis, sheds new light on the role of the various cations in the silicate structure. Important modifications in the structure of the pigment on alteration are also revealed, in particular leaching of alkali and the formation of silanols, which subsequently condense to create new bridging Si-O-Si bonds and molecular water in the glass. The sensitivity of the glass to dry conditions creates a tendency towards shrinking and cracking, which is very likely a contributing factor in the loss of cohesion, breakdown and blanching often observed in paint containing degraded smalt.
This article presents the results of physical-chemical analyses of samples of rock art painting a... more This article presents the results of physical-chemical analyses of samples of rock art painting and green pigments from the Atacama Desert in Northern Chile. The results allow us to incorporate a new technology, pigment production, into the mining and production process of copper that had previously been associated with lapidary production and metallurgy. The article also discusses the importance and implications of these results in relation to exchanges that would have occurred during Late periods (900-1550 A.D.) in and around this desert region.
Les Égyptiens accordant une place toute particulière à la polychromie, l'étude de ce matériel ne ... more Les Égyptiens accordant une place toute particulière à la polychromie, l'étude de ce matériel ne semble plus toujours d'actualité, puisque l'on pense, à tort, que toute la lumière a déjà été faite dans ce domaine. Il apparaît encore aujourd'hui que la connaissance qu'avait la civilisation égyptienne des minéraux dépasse souvent l'idée que nous nous en faisions. Ainsi, l'usage de plusieurs minerais jaunes pour des teintes voisines, goethite, orpiment ou jarosite témoigne de l'étendue du savoir des Égyptiens. Les identifications fines de certaines couleurs amènent à élargir l'étude de la couleur à des notions touchant au symbolisme, aux échanges commerciaux ou encore aux secrets d'ateliers.
Dominique Faunières, restauratrice du patrimoine ([email protected]). Sandrine Pagès-Camagna, ingé... more Dominique Faunières, restauratrice du patrimoine ([email protected]). Sandrine Pagès-Camagna, ingénieur de recherches, C2RMF, département Recherche ([email protected]). Charlotte Riou, conservatrice chargée des sculptures au musée des Augustins de Toulouse ([email protected]). Résumé. Notre-Dame de Bonnes-Nouvelles, Vierge à l'Enfant du xiv e siècle conservée au musée des Augustins de Toulouse (RA 511), a retrouvé récemment des témoins importants de son exceptionnelle polychromie. Un décor peint, riche et complexe, a pu être ainsi redécouvert. Sur le manteau de la Vierge, un semis de paons, de branchages fleuris et de motifs floraux en accolade sur un fond blanc contraste avec les fleurs de lis dorées sur un fond bleu du revers. Le voile de la Vierge, qui enveloppe également l'Enfant, présente des aigles dorées et des fleurettes stylisées, là encore sur un fond blanc. Le rouge de la robe offrait une touche d'éclat supplémentaire à cet ensemble d'un raffinement extrême. Abstract. Important elements of the exceptional polychromy of Our Lady of Good Tidings, a 14th-century Virgin and Child now in the Musée des Augustins, Toulouse (RA 511), have recently been restored. A rich and complex decor has thus been uncovered. On the Virgin's cloak, peacocks, blossoming branches and accoladed floral motifs on a white background contrast with gilded fleurs-delis on a blue background on the inside of the garment. The Virgin's veil, which is also wrapped around the Child, is adorned with gilded eagles and stylized fleurettes, again set against a white background. On the robe, the use of red offers an added touch of brightness to this extremely refined ensemble.
Verdigris is a green copper organometallic pigment, widely used in paintings during the fifteenth... more Verdigris is a green copper organometallic pigment, widely used in paintings during the fifteenth and sixteenth centuries. With ageing, chromatic modifications like browning or darkening can be observed on those green painted layers. An original but crucial approach has been developed based on the characterization of a reference neutral verdigris pigment-anhydrous copper acetate-and model samples, made of verdigris and linseed oil. Samples have undergone artificial ageing (temperature, light) to reproduce the color change effect. They were analysed before and after accelerated ageing tests by a complementary set of classical techniques: colorimetry, electron paramagnetic resonance, X-ray absorption spectroscopy, and UV-visible absorption. Our experiments revealed that the incorporation of the verdigris pigment in linseed oil induces a transformation of the copper acetate bimetallic structure, with the formation of monomeric species. These monomers, however, are not directly responsible for the darkening. The chromatic alteration seems instead linked to the transient formation of Cu(I) in the copper complexes of the pigment/oil system. This formation could be initiated by ambient light absorption through ligand-to-metal charge transfer, which favors the decarboxylation of the copper complexes leading to the reduction of Cu(II) into Cu(I). Moreover, dioxygen can react with partially decarboxylated dimers to form peroxy-Cu dimer complexes that can be responsible for the darkening.
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Papers by Sandrine Pagès-camagna
Abstract :
A study of ancient surface treatments (painting and gilding) on Greek terracotta figurines has been carried out at the Louvre museum over the last 15 years. The research project is now focusing on the art of gilding (chrysôsis in Greek) and its ancient craftsmanship. Results presented here document some twenty objects of Attic, Beotian, South-Italy and Eastern Greece production (Myrina, Smyrna), dated to the IVth century B.C. – IInd century A.D.. Through a careful autopsy of the remaining physical evidence, the aim is to better understand and characterize the degree of technicality involved (did it require the specific expertise of a gilder’s ?). Archaeological traces provide indeed the best clues on the technè of ancient craftsmen. The study includes an in-depth examination of the figurines with a digital video-microscope, and non invasive elemental and structural analysis of the gold leaf, ground (« bolus ») and preparation layers. It discusses processes in the gilder’s work and allows for a better appreciation of the high quality of workmanship involved. Refined finishing treatments such as burnishing have been detected as well as « pictorial », light and shadow effects unknown so far. It concludes with reflections on the fonction of the objects.
Abstract :
A study of ancient surface treatments (painting and gilding) on Greek terracotta figurines has been carried out at the Louvre museum over the last 15 years. The research project is now focusing on the art of gilding (chrysôsis in Greek) and its ancient craftsmanship. Results presented here document some twenty objects of Attic, Beotian, South-Italy and Eastern Greece production (Myrina, Smyrna), dated to the IVth century B.C. – IInd century A.D.. Through a careful autopsy of the remaining physical evidence, the aim is to better understand and characterize the degree of technicality involved (did it require the specific expertise of a gilder’s ?). Archaeological traces provide indeed the best clues on the technè of ancient craftsmen. The study includes an in-depth examination of the figurines with a digital video-microscope, and non invasive elemental and structural analysis of the gold leaf, ground (« bolus ») and preparation layers. It discusses processes in the gilder’s work and allows for a better appreciation of the high quality of workmanship involved. Refined finishing treatments such as burnishing have been detected as well as « pictorial », light and shadow effects unknown so far. It concludes with reflections on the fonction of the objects.