Photographic copy paper exposure calculator - has extreme valve stores assigned to sensors ascertaining lightest and darkest image points

摘要

The measuring arrangement is for exposure and contrast measuring devices as darkrooms. Two sensors are sequentially switched on to ascertain the lightest and darkest image points. The outputs are fed to two parallel, extreme values stores - one for max. and one for min. A calculator ascertains the mean exposure light intensity or exposure time and the paper grade for best contrast results. This eliminates all subjective evaluation from the photo-laboratory technician. The extreme values can be stored in digital or analogue form. The image points can be measured in any sequence.