1. A method of controlling a printer to print of an image, the printer having a predetermined marking material printed dot size, the method comprising the steps of: rasterizing the image and defining halftone super pixels within the rasterized image; wherein each super pixel is a matrix of pixels of said predetermined dot size; calculating the average density of the marking material within the super pixels; selecting a printed dot size larger or smaller than said predetermined dot size and selecting a pattern from a plurality of patterns for marking the pixels within the super pixels as a function of the selected printed dot size so as to expand the distribution of printed densities printable by the printer.