Patent ID: 7573609

Claim:
A method of printing a pixel with a printing apparatus including a processor, wherein the pixel is defined by C 1 , M 1 , Y 1 , K 1 color values having a sum that is not less than a maximum allowed paper coverage max_cov that is set to a greater of (1) a preset ink limit preset_cov and (2) the maximum of the C, M, Y color values, comprising: obtaining an adjusted cyan color value Cadj that depends on C 1 and K 1 , an adjusted magenta color value Madj that depends on M 1 and K 1 , and an adjusted yellow color value Yadj that respectively depends on Y 1 and K 1 ; assigning a maximum of the Cadj, Madj, Yadj values to max_color; assigning a middle of the Cadj, Madj, Yadj values to mid_color; assigning a minimum of the Cadj, Madj, Yadj values to min_color; selecting a black color value K that is not greater than a minimum of min_color and (Cadj+Madj+Yadj−max_cov+K 1 )/2; adding K 1 to K to obtain a black output color value Kout; obtaining a max_color_out value by calculating (T−mid_color), wherein T=max_cov−K 1 −min_color+K; obtaining a mid_color_out value by calculating (T−max_color); obtaining a min_color_out value by calculating (min color−K); obtaining a secondary color value S_color by calculating (max_color+mid_color−K−T); assigning each of max_color_out, mid_color_out and min_color_out to one of Cout, Mout or Yout depending on the relative magnitudes of the Cadj, Madj, Yadj color values; half-toning Kout, Cout, Mout, Yout, and S_color; and printing the pixel on a medium by a print engine.