Photochrom

thumb|280px|1890s photochrom print of Neuschwanstein Castle, [[Bavaria, Germany]] Photochrom, Fotochrom, Photochrome or the Aäc process is a process of colorizing from a single black-and-white negative with subsequent photographic transfer onto lithographic printing plates. The process is a photographic variant of chromolithography (color lithography). Because no color information was preserved in the photographic process, the photographer would make detailed notes on the colors within the scene and use the notes to transfer the image through colored gels onto the printing plates.

==History== The process was invented in the 1880s by Hans Jakob Schmid (1856–1924), an employee of the Swiss company Orell Gessner Füssli—a printing firm whose history began in the 16th century. Füssli founded the stock company Photochrom Zürich (later Photoglob Zürich AG) as the business vehicle for the commercial exploitation of the process and both Füssli and Photoglob continue to exist today. From the mid-1890s the process was licensed by other companies, including the Detroit Photographic Company in the US (making it the basis of their "phostint" process), and the Photochrom Company of London.