title: Enhancement of ninhydrin- or DFO-treated latent fingerprints on thermal paper.
abstract: 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.
authors: Research, Development, and Testing of Fingerprint Detection Methods Kriminaltechnisches Institut des Bundeskriminalamts, KT 41-2 Wiesbaden, Germany. lothar.schwarz@bka.bund.de
authors: Lothar
authors: L
authors: Schwarz
authors: Inga
authors: I
authors: Klenke
mesh_terms: D001372:Aza Compounds; D001392:Azocines / Q000737:chemistry; D003878:Dermatoglyphics; D006801:Humans; D007202:Indicators and Reagents; D009555:Ninhydrin; D010209:Paper; D011725:Pyridines / Q000737:chemistry; D011759:Pyrrolidines / Q000737:chemistry; D011760:Pyrrolidinones / Q000737:chemistry; D013499:Surface Properties
chemical_list: C406982:1,8-diazafluoren-one; C521343:1-octyl-2-pyrrolidone; D001372:Aza Compounds; D001392:Azocines; D007202:Indicators and Reagents; D011725:Pyridines; D011759:Pyrrolidines; D011760:Pyrrolidinones; C021249:4-pyrrolidinopyridine; C000110:2-azacyclooctanone; C040765:N-cyclohexyl-2-pyrrolidone; D009555:Ninhydrin