 The technique, if used with a camera not specially designed for contact printing, runs the risk of jamming the camera, due to the double thickness of film in the gate, and damaging both the exposed and unexposed stock.On the other hand, because both strips of film are in contact and are handled by the same film transport mechanism at the same time, registration is kept very precise.Special cameras designed for the process were manufactured by Acme and Oxberry, amongst others, and these usually featured an extremely precise registration mechanism specially designed for the process.