NCJ Number
75762
Journal
Journal of Forensic Sciences Volume: 24 Issue: 1 Dated: (January 1979) Pages: 140-147
Date Published
1979
Length
8 pages
Annotation
A survey of 200 random automobile paint chips with a standard forensic laboratory examination procedure (microscopic examination, solvent reactivity tests, instrumental analysis of organic constituent, and instrumental analysis of inorganic constituents) served to differentiate all samples.
Abstract
Specimen characteristics were tabulated throughout the examination to evaluate their frequency of occurrence in samples similar to those encountered in case work. Ninety-four percent of the samples were differentiated by microscopic examination and solvent reactivity tests. Of the remaining 6 percent that were undifferentiated, none of the paint chips had more than three layers. This observation leads to the conclusion that the probability of two paint chips originating from different sources is extremely remote when they have numerous layers (six or more) consistent in color, tint, type of finish, layer thickness, and reaction to acetone, sulfuric acid, and diphenylamine test solution. Ninety-seven percent of the samples were differentiated without the use of elemental analysis. For maximum differentiation capability, at least one instrumental analysis technique for organic components and one for elemental components should be incorporated into the analytical scheme when sample size permits. A review of the literature reveals the lack of frequency of occurrence studies for automobile paint evidence. Additional studies are being initiated to further assess the statistical value of this type of class evidence. Tables and 12 references are included. (Author abstract modified)