NCJ Number
208568
Journal
Journal of Forensic Sciences Volume: 50 Issue: 1 Dated: January 2005 Pages: 64-72
Date Published
January 2005
Length
9 pages
Annotation
This paper describes the application of infrared chemical imaging to the visualization of fingermarks, with and without cyanoacrylate fuming, and it assesses the future possibilities of this technique.
Abstract
The instrumentation for infrared chemical imaging is first described. It generally uses a focal plane array (FPA) detector that can be envisioned as thousands of discrete detectors (pixels) laid out in a grid pattern. Because of the large number of narrow, well-resolved absorbance bands that compose the infrared spectrum of organic (carbon-based) compounds, infrared chemical imaging offers potentially fewer problems with background interferences. This advantage can be exploited by using suitable reagents for the imaging of fingermarks. Criteria for a suitable reagent are outlined. In testing this method in the current study, latent fingermarks were placed on clean, dry glass microscope slides and freshly cleaned and dried circulated Australian polymer $5 banknotes, which has proven to be one of the most challenging surfaces for the development of fingermarks. In one experiment, a fingermark was placed on an infrared reflective (metal oxide-coated) microscope slide. Fresh latent fingermarks from a good donor were developed by using a purpose-designed forensic cyanoacrylate fuming cabinet. Infrared chemical imaging of fingermarks was conducted by using a Digilab Stingray system. The study found that the maximum reduction in background interference that impaired fingermark visualization was achieved with the use of a fingermark reagent with a sufficiently intense and isolated infrared absorption band. Potential reagents include those with an intense C=N vibration. Work is underway to synthesize and isolate such reagents, applicable to a variety of fingermark substrate surfaces. 8 figures and 19 references