Abstract: This invention relates to a method and apparatus for the electronic screening of a graphic image to be reproduced by printing. The density of the graphic image is determined repetitively during the digital generation of each dot which will form a part of the half-tone image when produced, and the dot is modified according to changes in the density. Thus the structure of any half-tone dot may be modified during its construction.

Abstract: This invention relates to apparatus for the reproduction of graphic material which is capable of operating a photo-composing device for reproducing the graphic material as an image on a photosensitive surface. The apparatus scans the graphic material with a light spot associated with a photosensitive device to produce an electrical output signal modulated according to the graphic information and which is employed to reproduce the graphic information on the photo-composing device. Control means are provided for positioning the scanning light spot at the start of each scan according to predetermined co-ordinates, whereby any scan can be commenced at any desired point on any item of graphic material within the field of scan of the light spot.