UV Reflectance Imaging
Definition
Photography using UV-A/near-UV-B incident radiation and a UV-pass, visible-blocking lens filter; reveals surface scatter differences in tissue and substrate chemistry not visible in ordinary light.
- Radiation used
- UV-A / near-UV-B incident light
- Filter setup
- UV-pass, visible-blocking lens filter
- Captures
- Reflected UV, not emitted fluorescence
- Reveals
- Surface scatter differences in tissue and substrate chemistry
Common questions
What kinds of surface features does UV reflectance imaging show that visible photography misses?+
It can reveal healed bruising patterns, subtle scarring, or ink and pigment differences that scatter UV light differently from the surrounding surface, even when no colour difference is visible to the naked eye.
Why use reflectance rather than fluorescence imaging for these targets?+
Some surface features scatter or absorb UV without fluorescing at all, so reflectance imaging captures a distinct type of contrast that a fluorescence setup, which depends on the material actually emitting light, would miss entirely.
Related terms
- ALS (Alternate Light Source)
- An adjustable-wavelength high-intensity light source with interchangeable excitation filters, used for scene examination across UV, visible, and NIR bands; examples include the...
- Barrier Filter
- An optical long-pass filter placed over the camera lens and worn as goggles by the examiner during ALS examination; blocks the excitation...
- DFO (1,8-Diazafluorenone)
- A chemical reagent for latent fingerprint development on porous surfaces (paper) that produces yellow-green fluorescence under 505-530 nm ALS excitation; effective on...
- Hot Mirror (IR-Cut Filter)
- The infrared-blocking filter bonded in front of the digital sensor in consumer and professional cameras; must be removed or bypassed for NIR...
- Infrared Luminescence (IRL)
- A photophysical process where visible-light absorption produces NIR emission; exploited in questioned-document examination to differentiate and sequence ink strokes with different luminescent...
- Laser-Induced Fluorescence (LIF)
- Fluorescence excited by a monochromatic laser source, providing higher photon density than a broadband ALS; used for fingerprints on difficult substrates and...
- NIR (Near-Infrared)
- The spectral region from approximately 700 to 1100 nm; used in reflectance and transmittance imaging of documents, obliterated text, soot patterns under...
- Stokes Shift
- The wavelength difference between the excitation peak and the emission peak of a fluorophore. A positive Stokes shift (emission at longer wavelength...
- Time-Gated Detection
- A laser fluorescence technique that delays camera shutter opening by nanoseconds after the laser pulse to allow short-lived background fluorescence to decay...
- UV-a
- The ultraviolet band from 315 to 400 nm; the primary band used for UV-reflectance forensic imaging of bruises, GSR, and bite marks...
- Vogeley 2002 Protocol
- A UV-A reflectance photography protocol published in the Journal of Forensic Sciences (2002) demonstrating improved detection of latent bruising on dark skin...