Pigments and fillers analysis is undertaken to establish the contents of an artist’s palette or identify the pigments used in a decorative paint scheme. It can often prove useful when dating paintings.
Studio techniques may involve a two way system: identifying the pigments by carrying out a number of the chemical reactions with powdered pigment particles under a microscope (dissolving in acids or observation of the characteristic crystals created as a result of the chemical reaction with reagents) or secondly visual observation of pigment dispersions (pigment powder, mounted in a clear-setting resin) with a polarising light microscope, using gemmological and mineralogical optical analytical processes.
Each type of pigment reacts differently to the polarized light rays so that every single particle can be identified. The chemical identification is also helpful in determining the type of metal foil used on the gilded object like a frame, a medieval painting or sculpture.
Other techniques can be used to examine a sample in more depth. For example; using non-invasive X-Ray Fluorescence (XRF) or scanning electron microscope with energy-dispersive x-ray (SEM-EDS) and Fourier Transform Infrared Spectroscopy (FTIR).