NTU Undergraduates' research April 2014 - Biosciences | Page 144

RESEARCH PROJECT

Comparative study of electrochromic enhancement of latent
fingerprints with existing development techniques on copper
surfaces
Rafaela S. Pereira 1, Emma L. Smith2

ABSTRACT
A novel and simple strategy for visualizing latent fingerprints on metallic surfaces has been developed by the use
of spatially selective electrodeposition of polyaniline (PAni). In this technique, the fingerprint residue acted as an
insulator to the electrochemical process (polymer deposition), so that the polymer could only be generated on the
areas without residue, between the ridges of the fingerprint deposit, which resulted in a negative image of the
fingermark with high contrast. Here, we present a study comparing the development and visualization of
nonvisible fingerprints on stainless copper substrates using this technique approach with two classical methods
(dusting with black and white powder and cyanoacrylate fuming (“superglue”)). Fingerprints samples were taken
from the same donor and were exposed to the same environment for systematically varied periods of time (up to
49 days). Comparing the electrochromic enhancement technique with commonly traditional methods used
(dusting and cyanoacrylate fuming), the new technique showed better success rates for old fingerprints.
KEYWORDS
Forensic science, latent fingerprints, metallic surfaces (copper), conducting polymer, polyaniline, polymer
deposition, electrochromic enhancement

Nottingham Trent University, April 2014