Spectral redundancy in a six-ink ink jet printer

摘要

We demonstrate for the multi-ink printers investigated that there are many spectral reflectances that can be produced approximately by a single printer through a large variety of different ink combinations. This spectral redundancy was evaluated for a pair of six-ink ink jet CMYKGO printers. Through use of the lookup tables, density maps were built illustrating the six-dimensional distribution of redundancy throughout colorant space. A tolerance of 0.01 RMS showed none of the inks in our CMYKGO systems to be fully replaceable by combinations of the other inks. However, when the tolerance was relaxed to 0.02 RMS, the degrees of freedom for matching spectra in the systems fall to five because the five chromatic inks cover the entire spectral gamut without the need of the black ink. Systematic relationships among the inks are reported, detailing the likelihood that combinations of printer digital counts may be replaced by largely different ones while preserving spectral reflectance to within an RMS spectral reflectance factor tolerance.