Taken from New Scientist
"Blood camera to spot invisible stains at crime scenes"
Call it CSI: Abracadabra. A camera that can make invisible substances reappear as if by magic could allow forensics teams to quickly scan a crime scene for blood stains without tampering with valuable evidence. The prototype camera, developed by Stephen Morgan, Michael Myrick and colleagues at the University of South Carolina in Columbia, can detect blood stains even when the sample has been diluted to one part per 100. At present, blood stains are detected using the chemical luminol, which is sprayed around the crime scene and reacts with the iron in any blood present to emit a blue glow that can be seen in the dark. However, luminol is toxic, can dilute blood samples to a level at which DNA is difficult to recover, and can smear blood spatter patterns that forensic experts use to help determine how the victim died. Luminol can also react with substances like bleach, rust, fizzy drink and coffee, causing it to produce false positives. The research appeared in Analytical Chemistry.