Colour copying method using a stored mask determined by scanning

摘要

A colour contact copier for opaque image receivers (26) has a scanning light source and an automatic control system for contrast matching and for the exposure intensity. The colour original (25) is scanned in advance in order to determine the initial exposure intensity and contrast matching limits to be expected for the opaque image receiver (26) and to set the necessary automatic exposure and contrast matching signals. The colour original (25) is further scanned in order to generate signals which represent an unsharp luminous mask for contrast control and are stored in a memory (35) such as an image storing tube. The opaque image receiver (26) is brought into close contact with the colour original (25) for the actual exposure scanning; in this process, the unsharp luminous mask is electronically superimposed on the scanning light source in order to obtain an automatic control of contrast and exposure of the image during the copying process. The exposure time for the exposure scanning is shortened even in the case of the use of insensitive reproduction material by means of combined modulation of intensity and speed. <IMAGE>