Photochrom

Photochrom, Fotochrom, Photochrome or the Aäc process is a process of hand-colouring photographs 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 hand paint the negative before transferring the image through colored gels onto the printing plates.