of process printing : using inks of 3 different colors
* * *
/three"kul'euhr/, adj.
1. having or characterized by the use of three colors.
2. noting or pertaining to a photomechanical process for making reproductions of paintings, artwork, etc., usually by making three printing plates, each corresponding to a primary color, by the halftone process, and printing superimposed impressions from these plates in three correspondingly colored inks.
[1890-95]
Useful english dictionary. 2012.