Offset printing forme with photocopy transfer - has properties of photoengraving forme on one side and normal offset copy on other side

摘要

A forme for offset printing is manufactured by transferring the picture or text to a printing plate with a light-sensitive copy coating. The image transfer is achieved by photocopying, and preparing the image zones and non-image zones to absorb ink and water respectively. A negative and a positive are formed in lines from a coated, copied, treated and inked photoengraving plate. They are then placed with their reverse sides adjacent to each other and deposited with the positive facing downwards. They are covered with a half-tone film which is exposed to scatter light and developed to produce a master with distorted grain effect, from which an offset printing forme is produced. The master is pref. a negative, and all photographic reproductions are pref. carried out in contact copying apparatus.