Chromolithography was the dominant color printing process of the late 19th and early 20th centuries, built on layering separate stones or plates, each inked in a different color, to produce richly saturated results that earlier printing could not match. It made mass-produced color imagery possible for the first time, and everything from travel posters to natural history plates to advertising cards came out of the same process. The pieces shown here are period originals printed in that tradition.