Details:
Summary:
The blackness of blacks and the purity of the colors of the printed product are always limited by the light which is reflected from the upper surface of the ink film. The amount of this unwanted light encountered at the viewing angle depends upon the roughness of the paper, the extent to which the ink fills or levels this roughness, the size and shape of the ink pigment particles, and the extent to which these pigment particles are covered by a film of dried ink vehicle. Therefore, both the paper roughness and absorptivity for ink vehicle as well as the ink and ink drying rate affect the degree to which colors and blacks are degraded by surface reflection. A new instrument has now been developed for measuring the colorimetric effect of surface reflection and a method of expressing the result in visually uniform color difference units has been adopted. Neither the Paper Surface Efficiency of the paper nor the gloss of the print provides satisfactory prediction of the extent of this color degradation.