A desired image based on digital data is printed on a substrate. A subset of the digital data relating to a portion of the desired image is identified, wherein pixels associated with the digital data are of a predetermined spatial relationship with pixels intended to be of a different color as the pixels...http://www.google.de/patents/US5550569?utm_source=gb-gplus-sharePatent US5550569 - Image processing for ink-jet printing with fast-and slow-drying inks
