Latent fingermark visualisation using reduced-pressure sublimation of copper phthalocyanine.
The sublimation of copper phthalocyanine (CuPc) at a temperature of 400°C under conditions of reduced pressure is shown to be an effective method of developing latent fingermarks on certain types of surface. Preliminary experiments on a limited selection of surfaces including paper, plastic and ceramic tiles were carried out using a simple apparatus consisting of a vacuum desiccator and a resistive heater. CuPc from the gas phase condenses preferentially on fingermark deposits, revealing deep blue patterns with excellent ridge detail clarity on light coloured surfaces. The technique is shown to be most effective on porous surfaces such as paper, but relatively ineffective on non-porous ceramic and plastic surfaces.
Materials Research Centre, School of Engineering, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom. Geraint.Williams@swan.ac.uk
Geraint
G
Williams
Hefin
H
ap Llwyd Dafydd
Alun
A
Watts
Neil
N
McMurray
D004396:Coloring Agents; D003878:Dermatoglyphics; D003890:Desiccation; D006361:Heating; D006801:Humans; D007211:Indoles; D009942:Organometallic Compounds; D016062:Porosity; D011312:Pressure; D013499:Surface Properties
D004396:Coloring Agents; D007211:Indoles; D009942:Organometallic Compounds; C015445:copper phthalocyanine