Image processing technology embeds signal (e.g., digital watermarks) within imagery during a raster image process(or). One claim recites: an image processing method of embedding a signal within imagery using a raster image processing (RIP), comprising: obtaining a plurality of elements representing a signal; and modulating a plurality of print structures within the RIP according to the plurality of elements, in which said modulating varies density, and direction or angle, of the plurality of print structures, and in which said modulating introduces the signal within the imagery. Of course, other claims, combinations and technology are described too.