Current color-printing technologies often use more than the minimum three or four inks: cyan, magenta, yellow, and black (CMYK). When the number of inks exceeds three, there is the usual color-management one-to-many mapping problem. Additional constraints have to be applied to achieve
greater determinacy. For CMYK ink sets, the black ink is constrained. When additional chromatic inks are added, traditional methods subdivide either colorimetric or colorant space to achieve a one-to-one mapping. However, these traditional methods cannot take advantage of all the ink combinations
available for improving image quality. Alternatively, additional constraints can be defined as perceptual metrics such as color constancy, graininess, color gamut, and color look-up table smoothness. A novel color separation algorithm was developed in order to optimize color look-up tables
for improved image quality. This algorithm was tested with a six-pigmented ink (CMYKGO), ink jet proofing printer. Various four and a six-ink look-up tables were created based on different metrics. The perceptual performances of these look-up tables in color reproduction accuracy, color inconstancy,
graininess and gamut volume were evaluated. The results show that the additional inks not only extend color gamut but also provided the potential to improve print quality.
Munsell Color Science Laboratory, Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology, Rochester, NY 14623
Publication date: March 1, 2008
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The Journal of Imaging Science and Technology (JIST) is dedicated to the advancement of imaging science knowledge, the practical applications of such knowledge, and how imaging science relates to other fields of study. The pages of this journal are open to reports of new theoretical or experimental results, and to comprehensive reviews. Only original manuscripts that have not been previously published, nor currently submitted for publication elsewhere, should be submitted.