Photopolymerization with the formation of relief images

Claim 1

PROCESS FOR COLOR PRINTING WHICH COMPRISES IRRADIATING AT LEAST 3 SEPARATE PLATES EACH COATED WITH A LAYER OF A SOLUTION CONTAINING AT LEAST 20% BY WEIGHT OF A VINYL MONOMER POLYMERIZABLE TO A SOLID POLYMER, AN ORGANIC PHOTO-REDUCIBLE DYE, AND A REDUCING AGENT HAVING A REDUCTION POTENTIAL INCAPABLE OF REDUCING SAID DYE IN THE ABSENCE OF LIGHT BUT OF SUFFICIENT STRENGTH TO REDUCE THE PHOTO-EXCITED DYE, SAID DYE AND REDUCING AGENT FORMING A STABLE SYSTEM IN THE ABSENCE OF LIGHT, WHICH UNDERGOES REDUCTION OF THE DYE UPON EXPOSURE TO VISIBLE LIGHT, SAID SOLUTION COMPRISING A SOLVENT FOR A SOLUBLE VINYL POLYMER CORRESPONDING TO A POLYMER OF SAID VINYL MONOMER, SAID DYE AND REDUCING AGENT BEING PRESENT IN SUFFICIENT AMOUNT TO PRODUCE FREE RADICALS FOR THE POLYMERIZATION OF SAID POLYMERIZABLE VINYL MONOMER WHEN IRRADIATED WITH VISIBLE LIGHT, WITH AN IDENTICAL PHOTONEGATIVE COLOR IMAGE, THE SOLUTION COATING EACH PLATE HAVING A PHOTO REDUCIBLE DYE WITH AN ABSORPTION MAXIMUM FOR A DIFFERENT PRIMARY COLOR, THEREAFTER WASHING THE UNPOLYMERIzED PORTION FROM SAID PLATES, DRYING THE PLATES, AND INKING EACH PLATE WITH AN INK HAVING A COLOR COMPLEMENTARY TO THE ABSORPTION MAXIMUM OF ITS DYE, AND THEREAFTER PRINTING SUPERIMPOSED IMAGES WITH SAID PLATES.