Abstract: A method and apparatus for the control of darkness/lightness in a digital image rendered by a printing system. The technique preferably employs templates to selectively apply different amounts of darkening (lightening) to borders of structures detected within the image dependent upon the need for darkening (lightening).

Abstract: A system for providing an output from a digital printing apparatus which is of higher resolution than the native resolution of the original image data. For a given center pixel area, image data corresponding to pixel areas generally neighboring the center pixel area are attempted to be matched to various templates which are consistent with curved lines in which resolution enhancement of the center pixel would be desirable. In a second stage of template matching, a second set of image data, corresponding to pixel areas further away from the center pixel than the first set of pixel areas, is also attempted to be matched to templates. The second stage of template matching helps to avoid resolution enhancement of image data which is related to a halftone image.

Abstract: A lead edge lightening circuit which will lighten a scan line based on a seven by seven pixel area surrounding the current pixel. The area is divided into four sub-areas, each of four by four pixels, and each having the current pixel at one corner. Each sub-area is summed and compared to a threshold number. If the threshold number is equalled or exceeded by at least one of the four sums, an overlay bit, which can be white or black, is output. The current pixel is replaced by a white pixel if a white pixel has been output, otherwise the current pixel remains unchanged.