Highly efficient cold light sources play a large part in this technology. With their help and a special fluorescence process, fingerprints and skin particles as well as blood and hair can be detected and photographically documented even on cartridge shells, plastic bags, or crumpled aluminum foil.
The kit consists of a cold light source with an LCD-display, a flexible glass fiber light guide with a diameter of up to 15 millimeters and a set of matched excitation and barrier filters. In the fluorescence process, evidence such as fingerprints on crumpled foil goes through a pre- and after-treatment with an acid compound and a fluorescent solution. Cold light irradiation and the use of the paired filters for the excitation and detection of fluorescent light then expose even the faintest contrasts. The light intensity of the 250 watt halogen reflector lamp exceeds that of conventional 150 watt lamps, permitting the previously difficult photo-documentation of the fluorescent evidence.
The German Criminal Investigation Bureau in Wiesbaden uses the kit to find fingerprints and organic traces, which are then subjected to further tests, such as a DNA analysis. The Rumanian police are currently equipping 50 crime scene vehicles with the kit, and the Forensic Science Services Metropolitan Laboratory in London, used by Scotland Yard among others, is testing another kit.
Schott Glas: Hot on the trail with cold light
The Forensic Kit KL 2500 LCD from the international technology group Schott, based in Mainz, Germany, will help investigators in the search for hard evidence.