GB235152A - Improvements in and relating to the production of printing plates or cylinders comprising both half tone and whole tone subjects - Google Patents

Abstract

235,152. Philippe, L. L., and Luginbuhl, H. June 6, 1924, [Convention date]. Photo-mechanical printing surfaces. - In the production of printing surfaces comprising half tone pictures and text or other line work, the method of adjusting the printing value of a halftone diapositive relatively to that of the text matter subsequently combined therewith so that only a single reproduction stage for exposing the etching resist and only a single etching may b necessary, consists in dyeing or colouring the half-tone diapositive, scraping away the gelatine surrounding the picture, and attaching to these parts a thin transparent sheet having the letterpress or whole tone matter thereon. The colouring or dyeing may be done before or after drying the diapositives and either chemically or by powdering. In addition to colouring the diapositive, and to avoid etching too deeply thick lines (e.g. thick characters, titles, &c.), these parts of the text may be printed in slightly transparent ink. In the Specification as open to inspection under Sect. 91 (3) (a) reference is made to other methods involving more than one exposure operation in the printing of the etching resist, or a dual etching operation, or the use of marks and varnishes for the different kinds of matter. This subject-matter does not appear in the Specification as accepted.