Published Online: 1 October 1976
Page Count: 9
Chemist, Centre of Forensic Sciences, Toronto, Ontario
(Received 18 December 1975; accepted 25 February 1976)
The examination of paint in this laboratory and many others is done, essentially, by two techniques. These are microscopy, for the physical characteristics and layer structure, and pyrolysis gas chromatography (PGC), for the resin type. X-ray diffraction is often used as an additional examination for establishing the nature of pigment and is effective in routine cases, particularly those involving automobile paint of varied colors. Microscopy, however, is of limited value in cases involving white and black paints, whereas PGC is less effective than microscopy in dealing with household paints, most of which contain alkyd-type resins. The X-ray diffraction pattern of household paints generally shows only titanium dioxide (TiO2 pigment and is of limited value. For the examination of white paints, therefore, we require an effective technique for differentiation. Analysis of the large number of trace elements contained in paint has been shown to be a useful technique in the discrimination of paints .
Paper ID: JFS10576J