NCJ Number
223869
Journal
Journal of Forensic Sciences Volume: 53 Issue: 4 Dated: July 2008 Pages: 812-822
Date Published
July 2008
Length
11 pages
Annotation
This study examined chemical reactions between latent fingerprints and a variety of metal surfaces by heating the metal up to 600 degrees C after deposition of the fingerprint.
Abstract
The findings show that it is possible for the inorganic salt content of fingerprint residue to produce a sufficiently corrosive redox reaction on metals such as copper, brass, and steel for the ridge detail present in the residue to be visualized. This reaction is significantly enhanced by the application of heat to the metal of up to 600 degrees C. The results of the heating showed a great deal of variation in the amount of fingerprint ridge detail displayed and produced a range of ridge detail from none at all to full development. The variation in the degree of ridge detail development between donors can be explained in terms of variations in the amount of salt secreted by various donors. The reaction was accelerated by elevated temperatures. The majority of the 360 fingerprints donated (53 percent) produced either a grade 3 or grade 4, which would make them suitable for identification. The degree of fingerprint enhancement was apparently independent of the elapsed time between deposition and heating, but was significantly dependent on both the composition of the metal and the level of salt secretion by the donor. The practical application of these findings for the enhancement of fingerprints deposited in arson crime scenes are discussed, as well as fingerprints contaminated by spray painting, or deposited on brass cartridge cases prior to discharge. Materials and methods used are described. 24 figures and 32 references