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Enhancement of Ninhydrin‐ or DFO‐Treated Latent Fingerprints on Thermal Paper
Author(s) -
Schwarz Lothar,
Klenke Inga
Publication year - 2007
Publication title -
journal of forensic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.715
H-Index - 96
eISSN - 1556-4029
pISSN - 0022-1198
DOI - 10.1111/j.1556-4029.2007.00416.x
Subject(s) - ninhydrin , acetone , petroleum ether , chemistry , chromatography , materials science , organic chemistry , biochemistry , amino acid , extraction (chemistry)
A new method for enhancement of ninhydrin or 1,8‐diazafluoren‐9‐one (DFO)‐treated latent fingerprints on thermal paper will be described. Most thermosensitive surfaces of thermal paper become dark when treated with DFO or ninhydrin petroleum ether (NPB) solution. This effect minimizes contrast between the developed fingerprints and the background. The new method described reduces this dark staining without removing the thermosensitive layer and parts of the developed fingerprints, as occurs with acetone washing. Through the new method, the developed fingerprints appear in sharp lines and high contrast. Extensive tests were performed, leading to an optimized working solution, which charges the paper with a minimum of chemicals, is cheap, and enables a large quantity of papers to be treated in a short time. The working solution contains commercially available, nonvolatile, nitrogenous organic compounds and can be used like the application of NPB solution by dipping.