Designed by the American Board of Forensic Odontology ABFO, this scale has become the standard for bitemark measurement and photography. The incorporation of three circles is useful in helping to compensate for distortion resulting from oblique camera angles. Graduations are all metric except for the width of the legs, which are 1-inch wide. The 1cm division lines are traced and extended across the photographic print to grid an image. Measurements within the image are then made relative to these inscribed 1cm grid lines to compensate for any distortion resulting from non-parallelism between the film and the object planes.

Specifications:
• Rigid, 1mm thick L-shaped laminated plastic
• Millimeter markings accurate to 0.1mm or better
• Overall size is 105mm x 105mm about 4" x 4"
• Gray areas have a reflectance value of approximately 18%
• Alternating black and white bars 1cm permit measurements from grossly over- and under-exposed photographs