Ink composition for ink jet printing

摘要

Cyan, magenta and yellow pigment-based ink compositions for ink jet printing are described; wherein the ink compositions each comprise a pigment, water, water miscible humectants and/or water-miscible organic co-solvents, surfactants, or mixtures thereof; wherein the normalized differential specular reflectance, NDeltaRS(X), for the cyan, magenta and yellow inks is less than 1.25, 0.50 and 0.30, respectively. NDeltaRS(X) is defined as the maximum value within a set of NDeltaRS(Xn) values in which each NDeltaRS(Xn) is the normalized specular reflectance for a density patch of a printed test image. The printed test image consists of a series of at least ten density patches printed such that the ink laydown on the patches increases incrementally, from no ink laydown to a maximum level generating a density of at least 1.5; and wherein NDeltaRS(Xn) for each patch is determined according to: 1 $N\mathrm{Delta}{R}_S\left(Xn\right)=\frac{\left[R_{S\max }\left(Xn\right)-R_{S\min }\left(Xn\right)\right]}{R_{S\mathrm{mean}}\left(Xn\right)}$ where, over the visible spectral region between 390 nm and 720 nm for