Abstract: Automatic incremental control of the exposure of a photosensitive image-receiving material during contact or projection printing is achieved by the use of a scanning exposing light beam, such as that from a cathode ray tube, wherein both the beam intensity and its rate of deflection can be varied in response to signals derived from a photodetector which views the scanning light after its passage through each incremental area of the transparency being reproduced.Embodiments capable of combined control of the intensity and velocity, or the dwell time, of the scanning light beam are disclosed, together with means for controlling exposure level and contrast.

Abstract: A conveying mechanism and flexible carrier for transporting a planar printing plate and flexible overlying mask from a flat loading station to a precisely-curved cylindrically-shaped scanning station, and back to the flat loading station, is disclosed. The vacuum carrier used is rigid in one axis and flexible in a second axis, and has a pair of reference strips which define a neutral bending axis for the plate and mask when the latter are wrapped around a pair of precisely machined cylindrical discs. By locating the flexible mask and printing plate outside the neutral axis of bending, both are placed in tension when wrapped around the discs. This maintains uniform contact between the plate and mask and prevents wrinkling of the mask as it overlies the plate.The carrier and discs support the plate and mask within a precise and uniform cylindrical plane for scanning with focussed beams of radiation.

Abstract: The conventional rear ground glass and vacuum back of a copy camera is replaced by an optically transparent platen and a flexible vacuum curtain. The vacuum curtain acts both as a copy viewing screen and as a photographic film or paper retainer. A vacuum channel with vacuum passageways is defined around the perimeter of the optically transparent platen to exhaust the air between the vacuum curtain and the transparent platen to thereby retain the light sensitive material to be exposed therebetween. The vacuum curtain is mounted on a roller that engages the transparent platen as the curtain is unrolled and rerolled over the sheet of photographic material.