Photographic method of making intaglio printing elements

Claim 1

THE IMPROVED PROCESS FOR MAKING PRINTING PLATES WHICH CONSISTS OF MAKING A CONTINUOUS TONE POSITIVE FROM AN ORIGINAL SUBJECT AND FROM THIS POSITIVE MAKING A SCREEN POSITIVE BY EXPOSING A PLATE BEHIND A HALF-TONE SCREEN TO LIGHT FROM A CONTINUOUS TONE POSITIVE OF THE ORIGINAL SUBJECT IN A PROCESS WHEREIN THE LENS OPENING IS OF SUBSTANTIALLY CRUCIFORM SHAPE IN WHICH THE LINES OF THE CROSS ARE DISPOSED SUBSTANTIALLY PARALLEL WITH THE LINES OF THE SCREEN, GIVING THE PLATE A SECOND FLASH EXPOSURE WITH THE CONTINUOUS TONE POSITIVE REMOVED, THEN DEVELOPING TO SILVER THE LATENT IMAGE, WITH A DEVELOPER THAT PRODUCES A DYE IN SITU WITH THE SILVER IMAGE, SAID DYE IMAGE HAVING A GAMMA VALUE OF AT LEAST 2.0, AND BLEACHING THE SILVER IMAGE, SECONDARILY EXPOSING SAID PLATE TO LIGHT INCIDENT ON THE SAME SIDE AS THE FIRST EXPOSURE, SAID LIGHT BEING OF A COLOR TO WHICH THE PHOTOGRAPHIC EMULSION IS SENSITIVE BUT WHICH IS ABSORBED BY THE SAID COLORED IMAGE, REDEVELOPING SAID PLATE TO A GAMMA OF AT LEAST 2.0 IN A DEVELOPER WHICH WILL NOT REDEVELOP ANY REHALOGENIZED SILVER NEGATIVE IMAGE WHICH MAY BE PRESENT, REMOVING THE COLORED IMAGE AND THEN FIXING THE PLATE TO REMOVE ALL RESIDUAL SILVER HALIDE, EXPOSING A SHEET OF SENSITIZED MATERIAL SUITABLE FOR PREPARING A PERMEABLE RESIST VARYING IN THICKNESS IN ACCORDANCE WITH THE TONES OF A CONTINUOUS TONE POSITIVE, ONCE BEHIND SAID SCREEN POSITIVE AND ONCE BEHIND THE CONTINUOUS TONE POSITIVE FROM WHICH SAID SCREEN POSITIVE WAS MADE, THE SUCCESSIVE PRINTS BEING IN REGISTER, PROCESSING THE SENSITIZED MATERIAL TO FORM AN ETCHING RESIST WHOSE THICKNESS VARIES IN ACCORDANCE WITH THE TONES OF THE CONTINUOUS TONE POSITIVE, SAID ETECHING RESIST BEING SUPERIMPOSED ON A PRINTING PLATE MATERIAL AND FINALLY ETCHING THE PRINTING PLATE MATERIAL TO VARYING DEPTHS IN ACCORDANCE WITH VARYING THICKNESS OF THE PERMEABLE RESIST.