An example of complementarity of Laser Induced Breakdown Spectroscopy and Raman Microscopy for wall paintings pigments analysis
Abstract
In this study, Laser Induced Breakdown Spectroscopy (LIBS) and Raman microscopy were used for wall paintings pigments identification. The use of Raman spectroscopy, giving molecular fingerprint of the compound, is nowadays widely spread in the archaeometry community, especially for pigment analysis. LIBS, providing elementary composition of samples with negligible damage, is a rapid non contact method, enabling layer-by-layer analysis, by ablating small amount of matter from the sample. This work deals with the behavior of pigments after a LIBS analysis, by characterizing of compound before and after the LIBS shot. Six commercial pigments were investigated in this study ultramarine, red lead, charcoal, a yellow and a red ochre, and a green earth. Raman spectra, acquired at the sample surface and at the bottom of the crater induced by LIBS analysis, are compared. Results obtained show that these pigments are well preserved after a LIBS analysis. Green earth analysis illustrates the powerful and complementary combination of these two techniques to obtain entire information for a sample.