Photographing evidence. Can of fizzy drink being photographed as evidence (camera not shown). The can was found near a crime scene and was dusted for fingerprints. Photographic scales have been stuck to the can. These record the position, orientation and size of the fingerprints. The alternate black and white markings mean that measurements can be taken from over and under exposed photographs. The crosshair circles at each end compensate for distortion caused by oblique camera angles.