Polarized microscopy can be useful for identifying pigments. Hypotheses based on observation made using polarized microscopy can be verified by chemical spot tests. Other analytical methods we commonly use to determine which pigments were used are FTIR (Fourier Transform Infrared Spectrometry) and SEM (Scanning Electron Microscopy)
Pigment analyses - Artbee Conservation Red lead particles revealed by polarized microscopy.
Pigment analyses - Artbee Conservation Red lead particles seen with polarized microscopy, polarized light
The characteristic bright red colour, as well as the green blue and yellow particles, are a strong indication that the pigment which is being observed is red lead.
Pigment analyses - Artbee Conservation Red lead particles, under microscope, after a chemical spot test has been carried out
A spot test using a drop of potassium iodide on the same pigment confirmed the presence of red lead (characteristic yellow colour, formation of crystals).