A system for placing a visible "watermark" on a digital image is disclosed, wherein an image of the watermark is combined with the digital image. The pixels of the watermark image are examined, and for each pixel whose value is not a specified "transparent" value, the corresponding pixel of the original...http://www.google.com.au/patents/US5530759?utm_source=gb-gplus-sharePatent US5530759 - Color correct digital watermarking of images
