Patent ID: 7499203
Filing Date: 2009-03-03
Classification: H04N

Abstract:
1. A method of printing a pixel with a printing apparatus including a processor, wherein the pixel is defined by C1, M1, Y1, K1 color values having a sum that is not less than a predetermined maximum VMAX which is greater than 0, comprising: obtaining an adjusted cyan color value Cadj that depends on C1 and KI, an adjusted magenta color value Madj that depends on M1 and K1, and an adjusted yellow color value Yadj that respectively depends on Y1 and K1; 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−VMAX+K1)/2; adding K1 to K to obtain a black output color value Kout; obtaining a max_color_out value by calculating (T−mid_color), wherein T=VMAX−K1−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.