Abstract: A method and apparatus for adjusting the dot or pixel density of a digital image which provides a toner or ink saving mode for high resolution printers. The invention is accomplished by generating a mask pattern which is applied to the image data prior to printing to reduce the number of dots actually printed. One hardware implementation of the invention uses a pair of finite state machines to generate a repeating mask which is offset from one row to the next as it is applied to the image data. This mask is applied to the data by logically ANDing bits in the mask to bits of image data. Wherever an OFF bit appears in the mask, the corresponding bit of image data will be OFF. Edge detection and preservation preserves any or all of the left, right, top or bottom edges of an image or character. Edge preservation compares contiguous pixels of an image before masking and preserves "transition" pixels, preserving ON pixels preceded or followed by an OFF pixel.