FINGERPRINTS - USE OF RADIO-ACTIVE GAS AND VACUUM METAL DEPOSITION FOR THE DEVELOPMENT OF LATENT FINGERPRINTS ON PAPER AND FABRICS

• NCJ Number: 10366
• Journal: Police Research Bulletin Issue: 19 Dated: (SPRING 1972) Pages: 16-21
• Author(s): J W GODSELL
• Date Published: 1972
• Length: 6 pages
• Corporate Author: Great Britain Police
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United Kingdom

Annotation

RESULTS OF OPERATIONAL APPLICATIONS OF THESE TWO METHODS ON GENUINE AND FORGED BANK OF ENGLAND NOTES AND PIECES OF FABRIC.

Abstract

IN THE FIRST METHOD THE SURFACE CONTAINING A LATENT MARK IS EXPOSED TO A RADIOACTIVE GAS WHICH WILL BE ABSORBED BY CERTAIN COMPOUNDS IN THE FINGER DEPOSIT. THE OBJECT IS THEN PLACED IN CLOSE CONTACT WITH AN X-RAY FILM FOR PERIODS RANGING FROM 2 TO 30 HOURS, THE RADIOACTIVE EMISSION RESULTING IN A POSITIVE IMAGE OF THE FINGERPRINT RIDGES AGAINST THE MORE OR LESS 'NOISY' BACKGROUND OF THE FILM. IN THE SECOND METHOD, EMPLOYING METAL DEPOSITION, THE OBJECT BEARING THE LATENT MARKS IS PLACED IN A BELL-CHAMBER AND AFTER EVACUATION TWO METALS ARE CONSECUTIVELY DEPOSITED ONTO IT. THE METALS ADHERE PREFERENTIALLY TO THE SURFACE AREAS NOT CONTAMINATED BY THE FINGER DEPOSIT, I.E. THE INTERSPACES BETWEEN THE RIDGES, RESULTING IN A NEGATIVE IMAGE. THE FINGERPRINTS ARE REVERSED DURING THE CONSECUTIVE PHOTOGRAPHIC PROCESS.