By permitting identification in situ of the characteristic spectrum of very small foreign, transparent or opaque enclosings, the Raman microsound laser proved itself to be a truly non-destructive microanalytical technique. This technique seemed to be particularly welladapted to the study of artwork, especially for the analysis of certain pictorial layers included in a transparent matrix such as glazing, varnish, or protective adhesives. These kinds of pictorial layers are in fact difficult to analyze by other techniques because of the risk of partially destroying the preserved work. The possibility of identifying the composition of these pictorial layers directly from the surface is seen as an important advantage. See also AATA 21-770 for related study.