Color printing reducing artifacts and banding by rendering black dots, replacing dots with process black, and adding non-black dots for different subsets of black dots

Abstract

A method of printing comprising setting a pixel black value of K for an ink limit and identifying each of black dots of a first subset of black dots having pixel black value K greater than the ink limit, and pixel color value of cyan, magenta, and yellow equal to zero. The method further comprises rendering only K for a pixel value for the first subset of black dots and replacing each of black dots of a second subset of black dots of a halftoned bit map for a predetermined area with a process black dot. The method still further comprises adding a non-black dot to each of black dots of a third subset of black dots of the bit-mapped data, wherein the halftoned bit map is generated by halftoning continuous tone data; wherein the black dots of the third subset comprises a percentage of all the black dots that tends to generally increase as a ratio of black coverage to total coverage in the predetermined area increases; wherein the first, second, and third subset comprises black dots that are mutually exclusive; and, printing the bit map.