NCJ Number
113369
Journal
Journal of Forensic Identification Volume: 38 Issue: 2 Dated: (March-April 1988) Pages: 57-61
Date Published
1988
Length
5 pages
Annotation
This article describes how to use infrared film to examine gunshot powder burn patterns, so as to obtain evidence not normally visible due to the faintness of the stain or the dark color of the fabric being examined.
Abstract
Regarding equipment and film, infrared radiation can be recorded with Kodak high speed infrared film 4143 in 4x5 sheets or Kodak high speed infrared film 2481 in 135 mm magazines. Almost any type of camera and lens can use the film. Both film loading and unloading should be done in total darkness. For most lighting arrangements, the visible light intensity does not have to be any greater than for visible light photography. A filter must be placed in front of the camera lens to block all visible light from striking the film. Because it is not possible to give the exact film speed index for infrared films, several trial exposures must be conducted. Most 35 mm camera lenses have an auxiliary infrared focusing mark. Extension of the lens to this point compensates for the differences in focus between visible light and infrared. A table indicates film processing procedure. 1 table, 4 figures.