Method of optimizing a reproduction of a picture copy includes scanning a picture copy optoelectrically for generating scanning signals, in accordance with the scanning signals, electronically screening the picture copy and inscribing a recording medium so that one of a plurality of screen fields on the recording medium corresponds to one or more scanning signals of the picture copy, forming each of the screen fields, respectively, of a plurality of elementary cells, and determining relative locations of the elementary cells so that a region of overlap between an inscribed and an adjacent non-inscribed elementary cell, respectively, is minimal.
The patterns can be used to reduce one or more undesirable effects such as moire or colour shift in coloured halftone images. Colour screens in the images are based on a combination of non-orthogonal mesh structures with parcels of printing dots which have common shape and size. Preferably the dots grow in mid tones by extending first towards their second, third or fourth nearest neighbours.
A multiple beam printer system having N laser beams receives print job information from a print host. A rendering application uses a threshold array to generate halftone image data from the print job. The threshold array is defined based on a spot function. The defined screen is non-orthogonal and includes Y pels in a direction that is perpendicular to a scanning direction of the laser beams where Y is an integer multiple of N. A distance between screen dots in pels is preferably equal to an integer multiple of N. The screen dot may be defined by a supercell encompassing two screen dots and having an odd number of pels in a direction that is parallel to the scanning direction. The spot function may include a snap feature that snaps a screen dot to the nearest printer grid pel. The spot function may include scaling to compensate for the distortion of the non-orthogonal screen dot.
