DECISION OF EXPOSURE AND CONTRAST BY PRESCANNING FOR ELECTROPHOTOGRAPHIC PRINTER SYSTEM

摘要

Automatic control of exposure level and contrast correction for a photographic printer is disclosed. The printer uses dynamic masking achieved by modulating the intensity and velocity of a CRT scanning spot. A prescan is employed to evaluate the negative and establish exposure level and contrast grade excursion limits for the subsequent exposure. Different control systems are disclosed for contact printing and projection printing.