Old fashioned two and three color printing often overprinted spot colors (colors generated by a single press run) to create a third color. Both Hungarian matchbooks (below) are two-color press runs of the same red and turquoise green. The print on the left makes use of a third, “black” color by running the red on top of the green (overprinting).
Four color process printing practically makes two or three color printing obsolete, and we know the reasons for this, but there’s a charm to two and three color printing. Skill and imagination were required to make use of overprints that created new colors without additional press runs.