Improving the surface quality of paint cross-sections for imaging analytical studies with specular reflection FTIR and Static-SIMS

The importance of surface preparation for imaging analytical studies of paint cross-sections is illustrated in this paper. A systematic dry polishing method was developed whereby the sample is fixed in a polishing holder. Using this method, the surface of existing paint crosssections was repolished and remeasured resulting in higher quality analytical data. A crosssection of the flesh paint of a polychrome sculpture by Ignaz Günther was studied with specular reflection Fourier Transform Infrared (FTIR) imaging. This sample showed a complicated layer structure with a thin intermediate layer that after improvement of the surface could be interpreted as a proteinaceous isolation layer. In the second example, a cross-section from a painting by Johannes Vermeer Diana and her companions was examined with static-Secondary Ion Mass Spectrometry (SIMS) in the context of the research on lead carboxylate aggregate formation in lead tin yellow paints. Here, the higher surface quality led to a better mass and spatial resolution.