Forensic Photography and Imaging
Forensic Photography and Imaging
This domain tests technical capture and image integrity: exposure control, lighting for specific evidence, scale discipline, and preservation of the original file. Expect questions about the correct light angle for a surface, or about what may and may not be done to an original image.
Exposure and lighting
The exposure triangle - aperture, shutter speed, ISO - governs brightness and depth of field. Small apertures increase depth of field but demand more light or higher ISO. Ambient-plus-flash balance preserves background context. Oblique or side lighting at a low angle reveals texture in impressions, tool marks, and latent residue; axial lighting controls reflection on shiny surfaces; painting with light builds illumination during a long exposure.
Evidence capture
Photograph overall, midrange, and close-up, with and without a scale placed in the same plane as the evidence and filling the frame. Use a tripod, a cable or timer release, and a consistent, documented lighting setup. Capture in RAW where policy allows and retain the original unaltered file.
Worked example
A latent print in dust on a dark glass pane. Correct approach: tripod-mounted camera, low-angle light from one side to graze the ridges, a black card behind the glass to raise contrast, an ABFO scale in the print's plane, the frame filled, exposures bracketed, and light positions recorded in the photo log. Enhancement for court is performed on a copy; the original stays untouched and hashed.
Traps
No scale, or a scale out of plane; on-axis flash that flattens texture; altering the original file; JPEG re-saving of a master image; and photographing after evidence has been moved.