NCJ Number
59423
Journal
Journal of Forensic Sciences Volume: 24 Issue: 3 Dated: (JULY 1979) Pages: 582-585
Date Published
1979
Length
4 pages
Annotation
A TECHNIQUE INVOLVING THE DETECTION OF LATENT FINGERPRINTS BY ARGON-ION LASER AND TREATMENT LEADING TO PHOSPHORESCENCE TO ELIMINATE SUBSTRATE LUMINESCENCE ARE DISCUSSED.
Abstract
THE DETECTION OF LATENT FINGERPRINTS BY ARGON-ION LASER INVOLVES ILLUMINATION OF THE EXHIBIT UNDER SCRUTINY WITH THE LIGHT FROM A CONTINUOUS-WAVE, ARGON-ION LASER FOLLOWED BY OBSERVATION AND PHOTOGRAPHY OF THE LUMINESCENCE FROM THE LATENT PRINT. HOWEVER, IN ALL CHEMICAL MODIFICATIONS OF PROCEDURES IMPLEMENTING THE TECHNIQUE, FLUORESCENCE FROM THE SUBSTRATE HOLDING THE LATENT PRINTS CAN BE PROBLEMATIC. FOR EXAMPLE, FLUORESCAMINE MAY FAIL IF STRONG GREEN OR YELLOW SUBSTRATE FLUORESCENCE OCCURS. THE SAME PROBLEM APPLIES TO INHERENT FINGERPRINT LUMINESCENCE. THEREFORE, IT WOULD BE USEFUL TO HAVE A PROCEDURE WHEREBY THE SUBSTRATE LUMINESCENCE, WHICH IS GENERALLY FLUORESCENCE, CAN BE ENTIRELY ELIMINATED. A TREATMENT LEADING TO PHOSPHORESCENCE IS SUGGESTED. IN THIS DEMONSTRATION, SIRCHIE DUAL-PURPOSE LATENT PRINT POWDER WAS USED TO ACHIEVE PHOSPHORESCENCE. RESULTS DEMONSTRATE THAT THE DETECTABILITY OF THE SIRCHIE POWDERS CAN BE STRONGLY ENHANCED WHEN USED IN THE PHOSPHORESCENCE DETECTION MODE IN THOSE INSTANCES IN WHICH STRONG BACKGROUND LUMINESCENCE OCCURS. BECAUSE PHOSPHORESCENCE IS DETECTED, NEITHER THE STRENGTH NOR THE COLOR OF THE SUBSTRATE FLUORESCENCE MATTERS. PHOSPHORESCENCE DETECTION WITH A UV LAMP IS ALSO FEASIBLE BUT NOT AS EFFECTIVE AS WITH A POWERFUL UV-OPTION-EQUIPPED, ARGON-ION LASER. SINCE THE PHOSPHORESCENCE DETECTION MODE ENTIRELY ELIMINATES BACKGROUND LUMINESCENCE, EVEN VERY FAINT PRINTS CAN BE PHOTOGRAPHED WITHOUT DIFFICULTY. A PHOTOGRAPH, DIAGRAMS, AND REFERENCES ARE PROVIDED. (LWM)