Laboratoire Of Recherche Et Of Restauration

Le Touquet – Paris-Plage, France

Laboratoire Of Recherche Et Of Restauration

Le Touquet – Paris-Plage, France

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Echard J.-P.,Laboratoire Of Recherche Et Of Restauration | Echard J.-P.,French National Center for Scientific Research | Bertrand L.,Synchrotron Soleil | Von Bohlen A.,Leibniz Institute for Analytical Sciences | And 9 more authors.
Angewandte Chemie - International Edition | Year: 2010

Figure Presented What is Stradivari's "secret"? The composition of the mythical varnish that coats Stradivari's violins has raised controversial assumptions for the past two centuries. By using a complementary array of analytical tools, the chemical microstratigraphy of these varnishes has been established. The results provide information on the materials and techniques that were used by the Master, with a detailed characterization of the varnish chemical equation presentation © 2010 Wiley-VCH Verlag GmbH &. Co. KGaA, Weinheim.


Thoury M.,National Gallery of Art | Thoury M.,French Natural History Museum | Echard J.-P.,Laboratoire Of Recherche Et Of Restauration | Refregiers M.,Synchrotron Soleil | And 5 more authors.
Analytical Chemistry | Year: 2011

UV-visible luminescence techniques are fre-quently used for the study of cultural heritage materials, despite their limitations for identification and discrimination in the case of complex heterogeneous materials. In contrast to tabletop setups, two methods based on the vacuum ultraviolet (VUV)-UV-visible emission generated at a bending magnet of a synchrotron source are described. The main advantages of the source are the extended wavelength range attained, the continuous tunability of the source, and its brightness, leading to a submicrometer lateral resolution. Raster-scanning microspectroscopy and full-field microimaging were implemented and tested at the DISCO beamline (synchrotron SOLEIL, France). Investigative measurements were performed on a sample from a varnished musical instrument and a paint sample containing the pigment zinc white (ZnO) in order to illustrate some of the challenges analyzing heterogeneous cultural heritage cross-section samples with the novel imaging approach. The data sets obtained proved useful for mapping organic materials at the submicrometer scale and visualizing heterogeneities of the semiconductor pigment material. We propose and discuss the combined use of raster-scanning microspectroscopy and full-field microimaging in an integrated analytical methodology. Synchrotron UV luminescence appears as a novel tool for identification of craftsmen's and artists' materials and techniques and to assess the condition of artifacts, from the precise identification and localization of luminescent materials. © 2011 American Chemical Society.


Bertrand L.,Synchrotron Soleil | Robinet L.,Synchrotron Soleil | Cohen S.X.,Synchrotron Soleil | Sandt C.,Synchrotron Soleil | And 6 more authors.
Analytical and Bioanalytical Chemistry | Year: 2011

The study of varnishes from musical instruments presents the difficulty of analysing very thin layers of heterogeneous materials on samples most of which are generally brittle and difficult to prepare. Such study is crucial to the understanding of historical musical instrument varnishing practices since written sources before 1800 are very rare and not precise. Fourier-transform infrared (FTIR) spectroscopy and imaging methods were applied to identify the major chemical components within the build-up of the varnish layers on a cello made by one of the most prominent French violin-makers of the eighteenth century (Jacques Boquay, ca. 1680-1730). Two types of FTIR imaging methods were used: scanning with a synchrotron-based microscope and full-field imaging using a 2D imager with a conventional source. An interpretation of the results obtained from these studies on the Boquay cello is that the maker first applied a proteinaceous layer, probably gelatine-based animal glue. He later applied a second layer based on a mixture of a drying oil and diterpenic resin from Pinaceae sp. From an historical perspective, the results complement previous studies by describing a second technique used for musical instrument finishes at the beginning of the eighteenth century in Europe. © Springer-Verlag 2010.


Bertrand L.,French National Center for Scientific Research | Bertrand L.,Synchrotron Soleil | Refregiers M.,Synchrotron Soleil | Berrie B.,National Gallery of Art | And 2 more authors.
Analyst | Year: 2013

In order to fully characterize the zinc white artists' pigment (ZnO), much used since the mid-nineteenth century, three samples collected in the early 20th century were studied using a combination of synchrotron and macroscopic photoluminescence spectroscopy and imaging. An improved microscope setup based on synchrotron microspectroscopy and microimaging was used to study the powders dispersed onto indium foil. The synchrotron setup offered a diffraction-limited resolution of 153 nm. The PL spectra of individual grains were measured and the distribution of particles' emission spectra was mapped at the nanoscale. The results revealed that while the samples have apparent homogeneous photoluminescence behavior at the macroscale (bulk), their PL signatures are inhomogeneous below 20 μm. At the nanoscale the three powder samples have quite different PL signatures. Different sources, perhaps even different batches, of zinc white might be readily differentiated using this method. © 2013 The Royal Society of Chemistry.


Daher C.,University Pierre and Marie Curie | Paris C.,University Pierre and Marie Curie | Le Ho A.-S.,French National Center for Scientific Research | Bellot-Gurlet L.,University Pierre and Marie Curie | Echard J.-P.,Laboratoire Of Recherche Et Of Restauration
Journal of Raman Spectroscopy | Year: 2010

Various natural organic film-making media from several chemical familieshave been used as varnishes. An improvement in the identification of thesematerials by a combination of Raman and infrared spectroscopies is presentedhere. Fourteen unaged reference samples representative of resins, glues, gumsand oils were analyzed. FT-Raman and infrared spectra were all compared in orderto discriminate the different classes of organic media by considering theirspectroscopic features. It led to a flowchart for material discrimination basedon simple, notable and specific criteria. It appears that the different families(gums, glues, oils and resins) and subfamilies (di/triterpenoids resins) areeasily differentiated thanks to their specific structural composition. However,differentiating between compounds from a same subgroup, for example diterpenoidresins, could be ambiguous because the spectra depend on the sample aspect, ageand degradations. Copyright © 2010 John Wiley & Sons, Ltd.


Latour G.,French Institute of Health and Medical Research | Echard J.-P.,Laboratoire Of Recherche Et Of Restauration | Didier M.,Laboratoire Of Recherche Et Of Restauration | Schanne-Klein M.-C.,French Institute of Health and Medical Research
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

We present multimodal nonlinear optical imaging of historical artifacts by combining Two-Photon Excited Fluorescence (2PEF) and Second Harmonic Generation (SHG) microscopies. Three-dimensional (3D) non-contact laser-scanning imaging with micrometer resolution is performed without any preparation of the objects under study. 2PEF signals are emitted by a wide range of fluorophores such as pigments and binder, which can be discriminated thanks to their different emission spectral bands by using suitable spectral filters in the detection channel. SHG signals are specific for dense non-centrosymmetric organizations such as the crystalline cellulose within the wood cell walls. We also show that plaster particles exhibit SHG signals. These particles are bassanite crystals with a non-centrosymmetric crystalline structure, while the other types of calcium sulphates exhibit a centrosymmetric crystalline structure with no SHG signal. In our study, we first characterize model single-layered samples: wood, gelatin-based films containing plaster or cochineal lake and sandarac film containing cochineal lake. We then study multilayered coating systems on wood and show that multimodal nonlinear microscopy successfully reveals the 3D distribution of all components within the stratified sample. We also show that the fine structure of the wood can be assessed, even through a thick multilayered varnish coating. Finally, in situ multimodal nonlinear imaging is demonstrated in a historical violin. SHG/2PEF imaging thus appears as an efficient non-destructive and contactless 3D imaging technique for in situ investigation of historical coatings and more generally for wood characterization and coating analysis at micrometer scale. © 2013 SPIE.


Echard J.-P.,Laboratoire Of Recherche Et Of Restauration | Bertrand L.,Synchrotron Soleil
Spectroscopy Europe | Year: 2010

A study was conducted to demonstrate complementary spectroscopic analyses of varnishes of historical musical instruments. The investigations were conducted to define optimal conservation conditions for these instruments, study the aging of materials in various contexts, and obtain a better understanding of the ancient instruments-making techniques. Micro-samples of varnish samples cut in cross section were analyzed using synchrotron radiation-based micro-Fourier transform infrared (SR-FT-IR) spectroscopy. Microformed thin slices were also analyzed in transmission mode of transflection mode for the investigations. Researchers were able to analyze the two layers of varnish on a set of instruments made by Antonio Stradivari. The FT-IR spectra also recorded revealed little difference between the two investigated layers and showed they were of oil-based media.


Latour G.,French Institute of Health and Medical Research | Echard J.-P.,Laboratoire Of Recherche Et Of Restauration | Didier M.,Laboratoire Of Recherche Et Of Restauration | Schanne-Klein M.-C.,French Institute of Health and Medical Research
Optics Express | Year: 2012

We demonstrate multimodal nonlinear optical imaging of historical artifacts by combining Second Harmonic Generation (SHG) and Two-Photon Excited Fluorescence (2PEF) microscopies. We first identify the nonlinear optical response of materials commonly encountered in coatings of cultural heritage artifacts by analyzing one- and multi-layered model samples. We observe 2PEF signals from cochineal lake and sandarac and show that pigments and varnish films can be discriminated by exploiting their different emission spectral ranges as in luminescence linear spectroscopy. We then demonstrate SHG imaging of a filler, plaster, composed of bassanite particles which exhibit a non centrosymmetric crystal structure. We also show that SHG/2PEF imaging enables the visualization of wood microstructure through typically 60 μm-thick coatings by revealing crystalline cellulose (SHG signal) and lignin (2PEF signal) in the wood cell walls. Finally, in situ multimodal nonlinear imaging is demonstrated in a historical violin. SHG/2PEF imaging thus appears as a promising non-destructive and contactless tool for in situ 3D investigation of historical coatings and more generally for wood characterization and coating analysis at micrometer scale. © 2012 Optical Society of America.

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