Electromagnetic Spectrum
Definition
The full range of electromagnetic radiation by wavelength, from gamma rays (shortest) to radio waves (longest). Forensic devices use UV, visible, IR and X-ray bands; rarely neutron.
Related terms
- Alternate Light Source (ALS)
- A device emitting light at selected wavelengths (typically 415 to 535 nm) used to detect biological fluids that fluoresce or absorb light...
- Detective Dye
- A fluorescent powder (typically anthracene or phenolphthalein-based) applied to banknotes or surfaces. Transfers to the suspect's hands on contact and fluoresces under...
- Fluorescence
- Light emission following absorption of light at a shorter (higher-energy) wavelength. Fluorescein absorbs blue-green excitation light and emits yellow-green light. The emitted...
- IR Reflectance
- Imaging under near-infrared illumination (715-1000 nm) to differentiate inks by their IR absorption: carbon-based inks remain dark, many synthetic dye inks become...
- Neutron Radiography
- Imaging technique using a thermal-neutron beam that penetrates dense metal and resolves light-element components like explosives, plastics and adhesives. Rare; used for...
Explained in
- Crime Detection Devices: UV, IR, X-Ray and Detective DyesThe full range of electromagnetic radiation by wavelength, from gamma rays (shortest) to radio waves (longest). Forensic devices use UV, visible, IR and X-ray...