FIELD: manufacturing of printing plates.
SUBSTANCE: printing plate manufacturing method for manufacturing printing plates based on image data divided into each colour and representing raster dots, includes: manufacturing a printing plate based on a reverse printing method in which reverse images of raster dots in one colour are formed, and printing is performed with imposition of raster dots of a different colour on the position of the reversible images; for each of the pixels, when the sum of the area ratio of the halftone dots of one colour and the area ratio of the halftone dots of the other colour is less than 100%, a gap is formed from the reversed image in one colour around the halftone dot of the other colour; and for each of the pixels, when the sum of the dot area ratio of one colour and the dot area ratio of the other colour is greater than 100%, a cover mask is formed so that the dot of the other colour penetrates the periphery of the dot of the same colour.
EFFECT: manufacturing of printing plates capable of limiting mixing and contamination of inks and providing easy registration and high colour reproducibility.
15 cl, 12 dwg
