NCJ Number
171928
Journal
Journal of Forensic Identification Volume: 47 Issue: 3 Dated: (May-June 1997) Pages: 283-286
Date Published
1997
Length
4 pages
Annotation
Using plastic materials as negatives in a photographic process provides a simple and effective procedure to supplement conventional photography of developed cyanoacrylate fingerprints on transparent plastic materials prior to any other physical or chemical enhancement procedures.
Abstract
The Identification and Crime Scene Unit of the West Haven, Conn., Police Department recently used this technique on zip-lock bags containing suspected rock cocaine. The bags were approximately 1 inch by 1 inch in dimension and light red to almost pink in color. They were processed with cyanocrylate fumes, which resulted in the development of 33 identifiable fingerprints. However, some photographs of the developed fingerprints did not yield satisfactory contrast through the use of conventional photography. Rephotographing the bags after removing, repackaging, and labeling the contents did not increase success. Therefore, the bags were individually laid flat in a 4 by 5 glass negative carrier with the developed print side up. The negative carrier was placed in a photographic enlarger. The enlarger was turned on, and the impact of the bag was focused on an enlarging easel. Kodak Polycontrast paper was placed in the easel and a Number 4 Polycontrast filter was placed in front of the enlarger lens. The photographic paper was exposed with the bag as the negative. The exposed photographic paper was developed according to the manufacturer's instructions. This technique greatly increased the clarity and contrast of the photographs. It also avoided grain distortion, because the evidence itself served as the negative. This technique is nondestructive, inexpensive, fast, and easy and requires no special training. Photographs