1. A method comprising: halftoning a source image, thereby converting multiple-level pixel input values, of each of plural color separations of a pre-rendered image, to binary output pixel values, the halftoning including error diffusion processing of a first separation of the plural color separations of the pre-rendered image after error diffusion processing a second separation of the plural color separations of the pre-rendered image, the error diffusion processing of the first separation comprising, for respective ones of the multiple-level input pixel values of the first separation, choosing corresponding binary output pixel values as a function of the error diffusion processing of the second separation; outputting a rendered image including the same plural color separations, the output rendered image being populated with, for the first separation, pixel information based on the respective magnitudes; and printing or displaying the output for each color separation to produce a halftoned image; wherein error diffusion processing is performed on each of the plural color separations in a given sequential order, and wherein the outputting of the rendered image comprises, for each output color separation, selecting image dots or pixels as active if a modified input for the image dot or pixel is greater than a particular threshold determined as a function of an error value associated with a corresponding dot or pixel in a previously processed color separation, and selecting image dots or pixels as inactive otherwise, the error value being calculated by determining a difference between an output of the previously processed color separation and a modified input of the previously processed color separation.