ABSTRACT
Paint, by which we mean any decorative or protective coating applied to a substrate, is one of the most widely encountered materials dealt with by forensic scientists working in the field of trace evidence. As a means of establishing association between people, places or things it has considerable potential as a source of evidence. Assuming that paint transfer has taken place, that paint is recovered and sent to the forensic laboratory for comparison, and assuming that whatever tests are performed cannot discriminate between the samples, the scientist has traditionally stated that the fragments under consideration match, or are indistinguishable, or some such phrase. As stated by Stoecklein in relation to traffic accidents: “If two multilayered paint fragments with the original layer sequence . . . are undifferentiable after using state-of-the-art examination techniques, it cannot be concluded with certainty that these samples came from the same source. . . . However, the probability is very low that a second automobile with identical morphological and chemical characteristics in its paint layer structure was in the vicinity of the crime scene at the time of the accident. Therefore, the evidential value of such results is nevertheless very significant”. [1] The inevitable follow-on questions to this kind of statement, therefore, are ‘So what? How significant?’, questions which are legitimately asked by investigators, fellow scientists and, ultimately, by a court of law.
