Selective etching of printing plates or cylinders - permits partial prepn. of cylinder to reduce prodn. time for late news items

摘要

Process for etching a printing plate or die (e.g. for rotogravure) corresp. with the images and alphanumeric charcters reqd., in which initially a part of the plate is etched to obtain a first set of images and characters, after which the entire die is Cr plated and any corrections made; the free part of the plate is then provided with a second set of images and characters by etching the Cr plating away where necessary. The Cr is pref. etched by a soln. which does not attack the Cr. Several modifications of this selective etching process are possible. The prodn. time for a printing plate is reduced to a min. In e.g. the printing of an illustrated magazine, the same cylinder for rotogravure can include advertisements and also pictures and/or texts of very recent news etc. where the time between prepn. of the plate and printing must be minimal.