| 摘要 |
412,441. Photolithographic processes. HACKETT, W. H., 32, Leeton Avenue, Coogee, and PRYKE, P. W., Burton Street, Lane Cove, both near Sydney, Australia. Aug. 30, 1933, No. 24042. Convention date, Aug. 30, 1932. Drawings to Specification. [Class 98 (ii).] Plates for successive colour printings to obtain a multi-coloured print of an original coloured picture are prepared from the usual " key " drawing indicating the colour components of the original by making a number of separate enlargements upon the grained surfaces of zinc or like metal plates and then marking each of these surfaces with black chalk or ink to form black and white representations of each of the different colour components of the original. Printing plates are obtained from these enlargements by photographic reduction upon other grained zinc or like metal plates from which the printing plates are then formed. Preferably the first enlargement of the key is obtained by photography, copies being obtained for example by transferring on to a zinc surface a dust impression from a dusted ink impression obtained by a pull on paper of the inked first enlargement.
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