Analyse non destructive des pigments par microsonde Raman laser : exemples de l’azurite et de la malachite
Résumé
By measuring the oscillation frequencies of atoms in the visible region, Raman spectrometry makes it possible to determine the polyatomic structure (ions, molecules, crystals) of organic or mineral compounds. The instrumentation has recently developed to such an extent that measurements can now be carried out on samples of very small dimensions (down to a few microns). This is done using the Raman laser microprobe, whose role in microspectrometry is briefly described. This method of analysis is non-destructive. It has been used successfully to identify various ancient pigments encountered on objects in course of conservation. The results obtained for samples of azurite and malachite are given, as well as a demonstration of the method’s application for the identification of azurite on a fragment of illuminated manuscript dating from the fifteenth century.