Philip B. Meggs: A history of graphic design, New York u.a. 1983, S. 184-185: “Popular graphics of the Victorian Era found its most prolific innovator in a German emigrant to America, Louis Prang, whose work and influence were international. After mastering the complexities of his father’s fabric-printing business, twenty-six-old Prang arrived in America in 1850 and settled in Boston. [...] Prang has been called ‘The Father of the American Christmas Card’ for his pioneering work in graphics for holiday celebrations. He had begun to produce Christmas images suitable for framing in the late 1860s, then he published Christmas card for mailing in England in 1873. His first American Christmas card was designed the following year. Typical images of these first Christmas cards were Santa Claus, reindeer, and Christmas trees. A full line of designs followed, and Easter, birthday, Valentine, and New Years card were produced yearly by L. Prang and Company during the early 1880s. Prang sometimes used as many as forty stones for one design. Part of the exceptional quality of his firm’s work was the fact that Bufford’s master black plate was dropped in favor of a slow building and heightening of the image through the use of many plates bearing subtle colors.”