Patent ID: 8547614

Claim:
A DOD (dot-off-dot) three colorant halftone image forming method for rendering an image using geometrically equivalent hexagonally tiled cluster halftone screens for rendering each colorant with an image rendering device, the method comprising: a) defining a base colorant halftone screen with hexagonally tiled halftone dots arranged in a hexagonal pattern, the hexagonally tiled halftone dots having a first fundamental frequency vector V h1 , a second fundamental frequency vector V h2 , and a third fundamental frequency vector V h3 , where V h3 is substantially equivalent to V h1 +V h2 ; b) defining a first colorant halftone screen as the base colorant halftone screen; c) defining a second colorant halftone screen as geometrically equivalent to the base colorant halftone screen, the second colorant halftone screen displaced from the first colorant halftone screen in a direction along the frequency vector V h1 −V h2 ; d) defining a third colorant halftone screen as geometrically equivalent to the base colorant halftone screen, the third colorant halftone screen displaced from the first colorant halftone screen in a direction along the frequency vector V h2 +V h3 ; e) applying the first, second and third colorant halftone screens, either collectively or individually, to the image to produce one or more halftone outputs representative of the image; and f) performing one of printing, either collectively or individually, the one or more halftone outputs, displaying the one or more halftone outputs, and further processing, either collectively or individually, the one or more halftone outputs.