1. A method for processing image data depending upon a plurality of predetermined error diffusion kernels to provide image data for an image display device, wherein the image data corresponds to a desired color image formed of plural picture elements (pels) in each of a plurality of channels, each of the plurality of error diffusion kernels corresponding to exactly one of the channels each pel corresponding to an area on the color image, and includes data corresponding to a desired level of enhancement of each pel in the desired image for each of the plural channels, the method comprising the steps of: determining for each channel and per image data at least three actual enhancement levels ranging from a low intensity to a high intensity, said actual enhancement levels including a first level corresponding to printing two dots in a pel area, a second level corresponding to printing a single dot in a pel area, and a third level corresponding to printing no dot in a pel area; modifying the desired level of enhancement for each pel of each channel based upon differences between the actual level of enhancement and the desired level of enhancement for at least one neighboring pel; correlating the modified desired level of enhancement in each pel of each of the channels with one of said actual levels of enhancement by: determining at least three ranges of desired levels of enhancement, each range corresponding to exactly one of said actual levels of enhancement, the ranges being mutually exclusive and contiguous between the low intensity and the high intensity; determining the range which includes the modified desired level of enhancement; and associating the modified desired level of enhancement with the actual level of enhancement corresponding to the range including the desired level of enhancement; calculating multi-level enhancement data for each channel by generating data corresponding to the actual level of enhancement which correlates with the modified desired level of enhancement; and transferring the multi-level enhancement data to the image display device.