NCJ Number
153471
Journal
Journal of Forensic Identification Volume: 45 Issue: 1 Dated: (January/February 1995) Pages: 19-24
Date Published
1995
Length
6 pages
Annotation
Color separation, either by electronic or photographic means, can facilitate the observation of fingerprint ridge detail when a known suspect's fingerprints are available and when some agreement of ridge detail has been discerned.
Abstract
Instances in which developed latent fingerprints reveal superimposed multiple impressions occur frequently in criminal investigations. Computer-based image enhancement can be used to separate multiple impressions according to gray level density. While this method can be effective if a difference in density exists between different impressions, multiple impression latent fingerprints developed with powders do not contain extensive density variations. Density values eliminated by computerized image enhancement remove all gray levels above or below specific thresholds, including part of the single impression being considered. Electronic image enhancement has also been employed successfully to separate multiple impressions with a color separation process that uses color scanners. As superimposed impressions are scanned, different red, green, and blue primary color channels can be electronically captured and enhanced independently. This same concept of color separation, but one that uses photographic instead of electronic procedures, can sometimes be beneficial when multiple impressions are involved. Color separation can be used to observe fingerprint ridge detail but may not be successful in all cases of multiple or superimposed latent fingerprints. When an identification is made using the color separation process, the use of film overlays provides a most convincing demonstration in court. 5 photographs