1. A method for filtering an image data subset of a page description data set, comprising the steps of: receiving a set of page description data including at least one image data subset; filtering image data of the image data subset by comparing adjacent pixels and coalescing adjacent pixels having substantially identical color values into pixel blocks wherein each of the pixel blocks is a plurality of pixels described by pixel block size, location in the image data subset, and an average of the substantially identical color values of the adjacent pixels.