NCJ Number
220420
Journal
Journal of Forensic Sciences Volume: 52 Issue: 5 Dated: September 2007 Pages: 1089-1096
Date Published
September 2007
Length
8 pages
Annotation
This study tested the suitability of Fourier transform infrared (FTIR) chemical imaging for the collection of fingerprint images from a wide range of surfaces that have traditionally posed problems for conventional fingerprint-detection methods, including polymer banknotes, various types of paper, and aluminum drink cans.
Abstract
Findings show that the fingerprint ridge detail on polymer banknotes achieved with FTIR chemical imaging is exceptional for a 30-day-old print on such a difficult background. Further work is continuing on the FTIR imaging of older prints. For aluminum drink cans, the most significant results were on sections of the can where ridge detail might be obscured by colored patterns or text under white light. In these cases, FTIR chemical imaging was able to produce superior fingerprint images in which the background patterns or text was completely eliminated and the ridge details of the fingerprint were pronounced. Attempts to acquire FTIR images of fingerprints on paper-based porous surfaces that had been treated with established reagents such as ninhydrin were all unsuccessful due to the swamping effect of the cellulose constituents of the paper. For each new surface, a systematic methodology was used in order to optimize settings such as spectral resolution, number of scans, and pixel aggregation, in order to reduce collection time and file-size without compromising spatial resolution and the quality of the final fingerprint image. Freshly deposited latent fingerprints were developed using a purpose-designed forensic cyanoacrylate fuming cabinet. Approximately 1 ml of ethyl cyanoacrylate was used for each treatment. Infrared chemical imaging of fingerprints was performed with a Digilab Stingray system. 4 tables, 7 figures, and 15 references