Mouseover to view semen stains under Blue illumination through a 495nm filter Mouseover to view tooth and bone fragments under UV illumination |
TECHNOLOGY FOR FORENSIC LIGHT SOURCE EXAMINATION | |||
Fluorescence Examination
The importance of fluorescence in forensics cannot be underestimated. An optical phenomenon that causes a material when illuminated with light of a particular waveband to emit light in another part of the spectrum, fluorescence is key to the search, detection, examination and enhancement of a wide range of evidence types. With a high intensity narrowband light source the forensic investigator can cause many evidence types to emit fluorescence. With appropriate viewing goggles the investigator can block out all light except for the specific waveband being emitted by the evidence making the often barely visible latent print appear to glow brightly. Different evidence types can be excited (caused to fluoresce) under different wavebands of light.
Body fluids generally best viewed under UV but also under violet or blue illumination Drug residues some illicit drugs glow brightly under UV illumination Hair some (but not all) human and animal hair fluoresce under violet and/or blue illumination Fibres fibres of many fdifferent materials can emit fluorescene at a range of wavebands Gunshot Residues GSR on a suspect or clothing is easy see under Blue or Blue/Green illumination Accelerants and Explosives can be seen to glow under Blue, Blue/Green and Green illumination Fingerprint Treatments Many latent fingerprint treatments consist of fluorescent dyes or pigments which are normally activated with UV or Blue light. |