orthochromatic sensitive to blue and green light. The name means ‘correct colour’. Orthochromatic film can be handled with a normal darkroom safe-light. panchromatic sensitive all colours – the usual film that is currently available. Must be handled in complete darkness. PC socket Prontor-Compur. Named after the two most prominent shutter manufacturers from the mid-20th century. … More Glossary of Photographic Terms (O to Z)