Abstract: In a system for producing screened images, for each set of image-representing signals derived from one rotation of an input scanner cylinder, n sets of screen-representing densities are derived corresponding to screen densities of parallel tracks each of which has a width which is a fraction of the screen pitch. The set of image-representing signals for a line of the image is modified n successive times as a function of the n respective sets of screen-representing densities and each of the n sets of screen-modified image-representing signals is applied in turn to modulate a single output element in an output scanner in which the scanning beam scans the image-reproducing area at a pitch that is n times finer than that of the input scanner.