While a general large layer dither volume provides great flexibility in
dither cell design, by decoupling different intensity levels, they are
inefficient to access since each color component requires the retrieval
of a different bit from the volume. Therefore in a multi threshold dither
volume for digital halftoning a contone color image, in the form of an
array of contone color pixel values to bi-level dots, there is allocated
for each dither cell location a fixed set of n thresholds defining n+1
intensity intervals within which said dither cell location is defined to
be alternatively not set and set.