Automatic exposure microfilm camera - has processed print measured by scanner and enables incorrect exposures to be repeated, using digital display of process

摘要

A microfilm camera (6) with automatic exposure control monitors the exposed and processed film, frame by frame and prepares a mean density reading which is compared with a reference value. A digital display (17) indicates if the exposure is successful, and if not what correction is being made to the exposure. A microcomputer controls the whole machine, and operates the exposure corrections to generate optimum prints. The control has a memory which stores the different frames so that if a frame is subsequently found wrongly exposed then the original can be retrived and a corrected exposure made. The density scanner plots a set pattern over the print and the microcomputer calculates a mean density value.