This invention is a method of producing a set of TRC's for a color
printer's secondary halftone screens that is correlated with the
printer's primary halftone screens. The method makes use of the
printer/screen characteristic data that is normally gathered during
screen calibration. However, instead of progressing from the data to a
normal calibration for the secondary screens, the method goes backward
through the data starting with the finished primary screen TRC's. The
method insures that for every primary screen density, the closest
possible secondary screen density is used when the same digital value is
specified.