NCJ Number
65110
Journal
Journal of Forensic Sciences Volume: 25 Issue: 1 Dated: (JANUARY 1980) Pages: 150-153
Date Published
1980
Length
4 pages
Annotation
A SIMPLE PROCEDURE FOR THE PREPARATION OF FINGERPRINT DUSTING POWDERS FOR USE IN DETECTION BY LASER IS DESCRIBED, AND A TYPE OF PORTABLE LASER SYSTEM IS OUTLINED.
Abstract
IN PREPARING A DUSTING POWDER FOR USE IN DETECTION BY LASER, ABOUT 0.1 GRAMS OF A FLUORESCENT DYE IS DISSOLVED IN ROUGHLY 50 ML OF METHANOL. APPROXIMATELY 10G OF FMP 01 MAGNETIC DUSTING POWDER IS ADDED TO THIS SOLUTION. THE MIXTURE IS STIRRED UNTIL THE METHANOL HAS EVAPORATED. GENTLE HEATING OR BLOWING AIR OVER THE SOLUTION EXPEDITES EVAPORATION. THE PREPARATION PROCEDURE IS SIMILAR TO THAT REPORTED BY THORNTON FOR COUMARIN 6. THE FLOURESCENT DYE IS DEPOSITED INTO THE PARTICLES OF THE DUSTING POWDER. THE POWDER IS APPLIED BY MAGNETIC BRUSH, AND LASER EXAMINATION REVEALS LATENT PRINTS BY THE FLUORESCENCE OF THE DYE. A NUMBER OF DYES HAVE BEEN SUCCESSFULLY USED (FMP 01, RHODAMINE 6G, RHODAMINE B, NILE BLUE A PERCHLORATE, OXAZINE 1 PERCHLORATE, 3,3' -DIETHYLOXADICARBOCYANINE IODIDE, AND 3,3' -DIETHYLTHIATRICARBOCYANINE IODIDE). DYES PROVIDING NEAR-INFRARED FLUORESCENCE ARE OF LITTLE USE, SINCE THE DUSTED LATENT PRINTS CANNOT BE LOCATED BY VISUAL INSPECTION. A SPECTROSCOPIC DETECTION SYSTEM USED WITH A HELIUM-NEON LASER (WITH ABOUT 50 MW POWER) MAY BRING LASER DETECTION OF LATENT PRINTS INTO THE REALM OF PORTABILITY (THOUGH NOT WITH THE SENSITIVITY ALLOWED BY POWERFUL ARGON LASERS), PROVIDED AT 110 V (OR 220 V) ELECTRICAL POWER IS AVAILABLE AT THE CRIME SCENE. PHOTOGRAPHS AND REFERENCES ARE PROVIDED. (AUTHOR ABSTRACT MODIFIED--RCB)