High Intensity Light Sources
The most traditional light sources used by Forensic specialists use a high intensity bulb and a series of specific cut off filters set to allow small bandwidth of light. Many of these lights sources have a high output but the use of filters significantly reduces this resulting in a low level of light on the fingerprint image. Today many light sources are based on LED technology, the LED’s produce a specific wavelength of light and don’t reduce the power of the output resulting in more brighter and more image fluorescence
The use of chemicals to cause fluorescence in fingerprints increases the recovered number of marks by at least 60%. For example the Superglue (Cyanoacrylate) process develops white to grey coloured impressions. If the background is white and the fingerprint is white, any developed fingerprints are very difficult to see. If a fluorescent dye such as Rhodamine 6g or Basic Yellow 40 is added the fingerprints instantly become very visible and can be used for identification. The two images below show a fingerprint developed with Superglue fuming on a packet of crisps/chips. In white light no impressions are visible, by using a light with a wavelenth of 460 - 510nm with a cut off filter of 549nm the fingerprint becomes visible.
Once the image has been photographed correctly it can now be enhanced using specialist forensic software. All captured images should be authenticated at the point of capture, and an audit should e created at the beginning that records in detail each enhancement step. This will enable the Forensic specialist to re reate the enhancement process as requested by the judicial system.
Have a look at the Image and Feature gallery to see a few of the available enhancement process.
A 16 LED array is equal to a 1000 watt Xenon
|Fluorescence BY 40|
|Fluorescence RH 6g|
|Fluorescence & FFT|
|High Intensity Light Sources|
|Court Room Presentation|
|Blood on Fabric|
|Leuco Crystal Violet|
|Digital Noise & Image Quality|