If two patterns are combined with each other they create a pattern of their own. Interference between two sets of fine pattern grids, the scanner samples and the geometric structure in the original image cause moire patterns. These artifacts are generally accepted as an inevitable quality degradation of the screening process. In this paper two patterns were combined to provide a moire- the first one with RGB sensor, the second one with the RG-BG sensors, both with the Siemens' star.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.