Alternate light source (ALS)
Any instrument delivering high-intensity narrowband illumination at a controlled wavelength to excite fluorescence in latent print residue, dye stains, or fluorescent powders; used with a matched barrier filter that blocks excitation wavelength and passes emitted fluorescence.
Explained in these topics
- Crime Detection Devices: UV, IR, X-Ray and Detective Dyes
- Specialised Photography: UV, IR and Close-Up at the Crime Scene
- Forensic Photography: Types and Applications
- Forensic Light Sources and Alternate Light Examination
- Cyanoacrylate Fuming, Alternate Light and Fluorescent Stains
- Lab Equipment and Chain of Custody for Fingerprint Casework