title: Synchrotron DUV luminescence micro-imaging to identify and map historical organic coatings on wood.
abstract: Deep ultraviolet (DUV) photoluminescence (PL) microimaging is an emerging approach to characterise materials from historical artefacts (see M. Thoury, J.-P. Echard, M. Réfrégiers, B. H. Berrie, A. Nevin, F. Jamme and L. Bertrand, Anal. Chem., 2011, 83, 1737-1745). Here we further assess the potential of the method to access a deeper understanding of multi-layered varnishes coating wooden violins and lutes. Cross-section micro samples from important 16(th)- to 18(th)-century instruments were investigated using synchrotron PL microimaging and microspectroscopy. Excitation was performed in the DUV and the near ultraviolet (NUV) regions, and emission recorded from the DUV to the visible region, at a submicrometric spatial resolution. Intercomparison of microspectroscopy and microimaging was made possible by radiometrically correcting PL spectra both in excitation and emission. Based on an optimised selection of emission and excitation bands, the specific PL features of the organic binding materials allowed a vastly enhanced discrimination between collagen-based sizing layers and oil/resin-based layers compared to epiluminescence microscopy. PL therefore appears to be a very promising analytical tool to provide new insights into the diversity of surface coating techniques used by instrument-makers. More generally, our results demonstrate the potential of synchrotron PL for studying complex heterogeneous materials beyond the core application of the technique to life sciences.
authors.affiliation: Equipe Conservation Recherche du Musée de la musique, CRC USR 3224, Cité de la musique, 221 avenue Jean Jaurès, F-75019 Paris, France. jpechard@cite-musique.fr.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Echard
authors.forename: Mathieu
authors.initials: M
authors.lastname: Thoury
authors.forename: Barbara H
authors.initials: BH
authors.lastname: Berrie
authors.forename: Tatiana
authors.initials: T
authors.lastname: Séverin-Fabiani
authors.forename: Alessandra
authors.initials: A
authors.lastname: Vichi
authors.forename: Marie
authors.initials: M
authors.lastname: Didier
authors.forename: Matthieu
authors.initials: M
authors.lastname: Réfrégiers
authors.forename: Loïc
authors.initials: L
authors.lastname: Bertrand