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DFO prints on a banknote fluoresce under Blue(A), Blue Green(B), Green(C), and Orange(D) illumination. Only under Orange (D) illumination does the background cease to fluoresce.

 

TECHNOLOGY FOR FORENSIC LIGHT SOURCE EXAMINATION

 

Multi-Spectral Illumination 

(Crime-lite)

 

When searching a crime scene or examining an item of evidence, the criminal investigator can dramatically improve results by using a range light sources with differing illumination wavebands.

 

Multi-spectral Crime Scene Investigation

By searching a crime scene using different coloured lights you can expect to find a variety of different evidence types that may have remained invisible to the naked eye under day light or a white light search. 

A single sweep of a crime scene using a UV light source may cause semen and body fluids to fluoresce brightly, while a second search with a blue light (when viewed through a yellow filter) could excite fluorescence in bone and tooth fragments or gunshot residues prevously invisible under UV.

 

Multi-spectral Fingerprint Examination

Fingerprint processes such as DFO, Rewop, Ninhydrin etc. have been formulated to fluoresce under a specific waveband of light e.g. Ardrox will fluoresce under Violet light while Redwop was designed to be viewed using Blue/Green illumination.

Some processes will fluoresce at more than one waveband. DFO can be visualised under Blue/Green, Green and Orange wavebands. This is particularly useful for the elimination of background fluorescence. For example if the surface upon which fingerprints have been deposited fluoresces under Blue/Green light it will be impossible to view the DFO treated fingerprint. By switching the illumination waveband to Orange, the background ceases to fluoresce leaving the DFO treated fingerprint clearly visible.

THE FOLLOWING PRODUCTS ARE AVAILABLE IN MULTIPLE WAVEBANDS

Crime-lite 82S a range of light sources for crime scene or laboratory

Crime-lite 42S a range of powerful dual-colour light sources 

Crime-lite 2 single-LED infrared light source

Crime-lite 8x4MK2 the multi-wavelength photographic ring light

Crime-lite ML2 laboratory light source with integral magnifier lens