PHOTOGRAPHIC ENLARGER OR COPYING MACHINE FOR COLOUR PRINTS

摘要

A photographic enlarger or copying machine for colour prints, with a measurement device to determine the density of a test copy, which is exposed with the enlarger by means of a reference specimen selected for testing the equipment. Light guides (15) convey light from the copying light source of the enlarger into a measurement plane outside the copying beam path, which takes the copies to be measured; a photoelectric measurement recorder (25) receives light reflected from the test copy. Depending on a difference in density between the test copy and a reference copy, the correction to the exposure valves are determined in such a way that a copy which is exposed under the new exposure conditions displays the density values of the reference copy.