Half-tone screen for color separation

Claim 1

A HALF-TONE SCREEN COMPRISING A TRANSPARENT SUPPORT, A PLURALITY OF SUPERIMPOSED, INDIVIDUAL DYE SCREENS ON SAID SUPPORT, EACH SCREEN COMPRISING INTERSECTING SERIES OF ADJACENT, PARALLEL ZONES OF DYE AREA WITH THE SAID ZONES OF EACH SCREEN EXTENDING AT A PREDETERMINED ANGLE OF INCLINATION TO THE DIRECTION OF EXTENT OF THE ZONES OF EACH OF THE OTHER OF SAID SCREENS, EACH OF SAID SCREENS HAVING HIGH OPTICAL DENSITY TO LIGHT OF A GIVEN COLOR AND LOW OPTICAL DENSITY TO THE REMAINING LIGHT PORTIONS OF THE VISIBLE SPECTRUM, EACH OF SAID SCREENS HAVING SAID HIGH OPTICAL DENSITY IN RESPECT TO A DIFFERENT PORTION OF SAID SPECTRUM AND EACH OF SAID ZONES HAVING AN AREA OF UNIFORM MAXIMUM OPTICAL DENSITY SYMMETRICAL WITH THE CENTER LINE THEREOF AND HAVING AREAS OF UNIFORM MINIMUM OPTICAL DENSITY ADJACENT AND PARALLEL TO EACH EDGE OF EACH OF SAID ZONES, EACH OF SAID ZONES VARYING SUBSTANTIALLY CONTINUOUSLY IN OPTICAL DENSITY BETWEEN SAID AREAS OF MAXIMUM AND MINIMUM DENSITY IN A DIRECTION TRANSVERSE TO THE DIRECTION OF EXTENT OF THE RESPECTIVE ZONE, THE COMBINED WIDTH OF SAID AREAS OF MAXIMUM AND MINIMUM OPTICAL DENSITY OF EACH OF SAID ZONES BEING LESS THAN THE FULL WIDTH OF THE RESPECTIVE ZONES.