Determining the Ideal Initial Printing Colorants in Electrophotography
by the Discrete Gradation Trajectories
Abstract
The accuracy and repeatability of the color reproduction in print is
determined by the fine tuning of the tone reproduction curves of the
basic printing colorants (most often this is CMYK). However, the
diversity of manufacturers of printing equipment and dyes introduces an
element of significant uncertainty about color uniformity. In addition,
the traditional approach does not take into account the effect of hue
change when applying the original dyes, as well as, the non-linearity of
the hue rise in high and low density areas. Determining the color of
base colorants that produces the most uniform tone change is an
important engineering challenge. Previously, there was no scientific
basis for such calculations. We recently proposed an alternative color
correction model based on gradation trajectories as an analogue of
gradation curves in the CIE Lab space. We have also described the
extension of the approach to double color overlay (gradation surfaces)
and its analytical and discrete implications. The trajectories are the
geodetic lines on gradation surfaces. In this paper, we propose using
the gradation trajectories to determine “ideal” or “true” initial
printing dyes for electrophotography. To simplify calculations, natural
color discretization in digital printing is used.