NCJ Number
224399
Journal
Journal of Forensic Identification Volume: 58 Issue: 5 Dated: September/October 2008 Pages: 515-523
Date Published
September 2008
Length
9 pages
Annotation
This article reports on the use of time-resolved luminescence of latent fingerprints in order to address the problems that occur when traditional luminescence methods are used in developing latent fingerprints on strongly fluorescent substrates.
Abstract
The testing found that when background fluorescence suppressed latent print phosphorescence, time-resolved luminescence of the prints produced a far more legible print than was achieved from traditional luminescence methods. Very good enhancement results were also obtained on light-reflecting backgrounds, such as aluminum foil. Additional research will be undertaken in order to investigate various paper types and porous surfaces. The pulsed light radiation (365 nm) used in the first stage of examinations by means of time-resolved luminescence required a station constructed particularly for developing latent fingerprints on nonabsorptive backgrounds (e.g., metal, glass, and plastic). The station incorporates a computer-interfaced pulse diode light, a CCD camera used for acquisition and summing up weak signals of time-resolved luminescence, and a controlling and acquisition computer station. This new electro-optical imaging station involves the application of pulsed illumination that is timed to activate when the light source is off and background fluorescence is eliminated. The operation cycle of the station for time-resolved luminescence acquisition is presented in one of the figures in this article. In the course of the examinations, a cyanoacrylate fuming method was applied first, followed by the europium chelate solution treatment, which absorbs strongly in the near ultraviolet and has a delayed emission in the red portion of the spectrum. Dedicated software allows for a change of all exposure parameters. 5 figures and 6 references