Advantages of the K3 System, a pigment inkjet printer system that uses three levels of achromatic inks, were investigated. It was found that by employing these achromatic inks throughout a large area of the constructed output data, in contrast to existing printers using conventional coloring sets this system offers a level of quality of short-term color drift behavior, dependency of light source(Metamerism), consistency across multiple printers and tonal gradation that satisfies the demands of professional photo users.
Tsuyoshi Sano, Shinichi Kato, Shuichi Kataoka, Kiyohiko Takemoto, "The Optimization of Pigment Ink Set for Large Format Printer" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP22), 2006, pp 214 - 217, https://doi.org/10.2352/ISSN.2169-4451.2006.22.1.art00054_1