Enhanced system, method and program for converting an externally defined four dimensional colorant (cmyk) into an equivalent four dimensional colorant defined in terms of the four inks (c′m′y′k′) that are associated with a given printer

Abstract

A unique combination of four colorants (C′M′Y′K′) of a given printer that is equivalent to an externally defined four colorant combination (CMYK) by having the same color values (e.g., L*a*b* values). A fourth colorant, e.g., black, (K) of the externally defined four colorant combination is mapped to an equivalent fourth colorant (K′) of the printer by matching optical density, reflectance, L* or similar color value. The L* value is found for various percentages of the fourth colorant of the printer by printing varying percentages of the fourth component and measuring its L*a*b* values and, assuming a* and b* are near zero, using the L* value. These values are inputted into an interpolation program. Then, patches of varying percentages of each one of the three color components of the printer (CMY) are printed out at varying percentages. The L*a*b* values for each patch are measured and inputted into an inversion/interpolation program along with the corresponding percentages of colorants of each patch. The externally defined four component colorant having L*a*b* values also used in the inversion/interpolation program, which creates a color transform table from CMY with various percentages of K of the externally defined four dimensional colorant to C′M′Y′ with various percentages of K′ of the four dimensional colorant of the printer by matching L*a*b* values.