When we talk about alternate light sources we are usually referring to the larger alternate light sources priced from $3,000 to $16,000. These are not easy to carry around with you to crime scenes on a regular basis.
We all carry flashlights and rechargeable Maglight or Streamlight in the patrol vehicle. The Blue Light Special fits on the head of the flashlight and has an amber-viewing shield attached on a swivel clip for viewing. It will fit in your crime scene kit and will be available when you need it. Though not as powerful as the larger units, it has its place because it is portable and cost effective to use. Latent fingerprints, which are treated with fluorescent fingerprint powder, usually have more detail than the same print developed with conventional methods. This unit will make semen, saliva, and urine fluoresce so it can be collected and sent to the lab for analysis. It will also illuminate some fibers, and its wavelength is absorbed by blood, making the blood appear black so that it can be easily seen and photographed.
This unit is handy to use at rape or death scenes to view the body and the scene for any evidence that cannot be seen by the naked eye. It can also be used at the hospital to scan a victim for semen stains on the body. Placing an amber lens on the camera to capture the images or shooting through the amber shield enables you to photograph these stains and prints.