The technique of impregnation-inclusion in epoxy resin followed by an ultramicrotome allowed researchers to obtain stratigraphic sections of paint samples less than 100 nanometers thick. The morphological study of pigments by electronic microscopy was followed by chemical identification using x-ray spectrometry coupled with electron microdiffraction analysis of their structure. A first application carried out on a painting by E. Manet, La Serveuse de bocks allowed to unambiguously characterize the cobalt blue, ultramarine, and white lead (hydrocerusite) pigments. But the nonstoichiometricalcharacter of the Naples yellow did not allow to arrive at a direct relationship between its crystalline parameters as measured, and the standards described in the classical literature. -- AATA