| 摘要 |
332,652. Sõchsisches Serumwerk Akt.-Ges., and Galetzka, A. May 1, 1929. Printing - surfaces. -A half-tone or line plate which can be used as a transparency or as a printing plate is made by coating a transparent base 1 with a transparent layer 2 capable of taking up moisture and swelling, coating this layer with an etchable metal coating 3, producing a photographic etchable image or design 4 on the metal coating, and etching the design through the metal coating without attacking the layer 2. When the plate is to be used for printing, the image is washed off and the layer 2 swells through the openings in the metal layer 3 forming ink-repelling areas. The layer 2 may be of gelatine or a cellulose ether or hydrate.
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