4 4 A 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 BY USING A THREE DIMENSIONAL TO FOUR DIMENSIONAL CONVERSION PROCESS

摘要

The system, method, and program of the present invention may receive externally defined four-dimensional colorants (e.g., CMYK) as input to determine the equivalent four pigment combinations used by a given printer. A color rendering dictionary is based on the following process, which is used by the printer to convert it every time a four-dimensional pigment is received as input. A number of patches having a variable percentage of a predetermined known combination of three primary colors (e.g., CMY) are printed. A different set of patches with a predetermined variable percentage of the fourth color (e.g., black) is printed. The L ^* a ^* b ^* values of these patches are measured. An inverse transform program is used to determine the equivalent CMY component percentages for the variable percentages of the fourth component based on the actually measured L ^* a ^* b ^* values in practice. These determined percentages of the CMY component and the known percentages of CMY are used to replace the fourth dye (K) for each of the original CMY combinations, known as a fourth dye substitution or black substitution. Also, under color addition may be performed at this time. Correlation is now established between the CMY combination and the equivalent CMYK combination. To further enhance the conversion process, and a patch of the new CMYK combinations can be printed, L ^* a ^* b ^* values are measured new ^{CMYK / L * a * b *} L * a is because the space is set using the inverse transform program ^* A conversion scheme from b ^* to CMYK is provided. To determine the printer's equivalent CMYK combination, an externally defined L ^* a ^* b ^* value for a four-dimensional dye is used in the conversion scheme.