UV Fluorescence Photography
Definition
Imaging where UV light excites a substance into emitting visible light, which is then captured with a visible-pass filter. The standard technique for semen detection on dark fabrics.
- Principle
- UV excitation, visible-light emission capture
- Filter used
- Visible-pass (UV-blocking) filter on the lens
- Primary application
- Semen detection on dark fabrics
- Light source
- UV-A or UV-C excitation source
Common questions
How does UV fluorescence photography differ from UV reflectance photography?+
Fluorescence photography captures visible light emitted by a substance after UV excitation, using a filter that blocks UV and passes only visible wavelengths, while reflectance photography captures UV light itself bouncing off the surface, using a filter that does the opposite.
Why is this technique preferred over an alternate light source for casework photography?+
It is not necessarily preferred over ALS, but produces a permanent, documented image of the fluorescence pattern for the case file, which a visual-only ALS examination on its own does not.
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...
- IR Reflectance Photography
- Imaging where IR light penetrates the surface and is reflected from layers beneath. Reads ink overwrites and obscured tattoos.
- Macro Reproduction Ratio
- The ratio of subject size on the sensor to actual size. 1:1 is life-size; 2:1 is twice life-size. Forensic macros are 1:1...
- Reflected UV Photography
- Imaging where UV light illuminates the scene and the reflected UV is captured. Reveals body fluids, certain fibres, and altered ink without...