How Changes in the Hues and Cleanliness of Process Inks Affect the Cleanliness of In Between Colors.

A study of process inks has shown that the cleanliness of the in between colors (greens, oranges, reds, violets and blues) is a function both of the hue and the cleanliness of the process inks. A table is given which will predict how a change in the hue or the cleanliness of a particular process ink will affect the cleanliness of the in between colors. For example, the cleanliness of the magenta and the cleanliness of the yellow determine the cleanliness of the reds and oranges made with them, rather than the hues of either ink. But the hue of any fairly clean magenta is responsible for the relative cleanliness or dirtiness of the blues and violets made with it, assuming that the same cyan is used in each case. It is possible to arrive at these conclusions from reflection density measurements of proofs of the process inks and the in between colors made with them. Several examples are given to illustrate these points.