Chemical enhancement of fingerprints on various porous and non-porous surfaces

Abstract

Latent fingerprints created by the transfer of perspiration from skin to a surface, require chemical enhancement to make ridge detail visible. This study contains two separate investigations, the first part investigates the chemical development of latent fingerprints on porous surfaces studying different paper types, using different chemical techniques. The second part of the study involves the analysis of fingerprints in which the transfer medium is blood. A side-by-side comparison of the available chemical techniques targeting a variety of porous and non-porous surfaces was carried out and thesensitivity of the chemicals was also tested through serial dilutions and concentration gradients of whole blood. Findings indicate that several conditions affect the quality of fingerprints. The degree of fingerprint ridge detail yielded during chemical development is influenced by factors such as the chemical technique used and the particular substrate from which the fingerprints are enhanced.