Superimposition of three dot screens with three primary colours - for recording images line by line and reducing moire effect

摘要

Three dot screens are superimposed by superimposing two square dot screens having the same screen constant a1 = a2 = a at angles of 0-45 deg., and a rhombic dot screen with the longer diagonal 2h = square root of 2 . a and the shorter diagonal c = a at an angle of 0 deg., with respect to a fixed coordinate system. Pref. the resulting screen combination comprises:- (a) square screen with screen constant a1 = a rotation relative to fixed coordinate system angle 1 = 0 deg. (b) square screen with screen constant a2 = a rotation relative to fixed co-ordinate system angle 2 = 45 deg. (c) rhombic screen with long diagonal 2h = square root of 2 . a with short diagonal c = a rotation relative to fixed coordinate system angle 3 = 0 deg. Moire effect is reduced, while the information content of the individual colour separations remains the same.