Photochrom Prints of Switzerland

Photochrom prints of Switzerland (Detroit Publishing Company, 1905)

Photochrom (also fotochrom or photochrome) is a process for producing colorized images from a single black-and-white photographic negative via the direct photographic transfer of the negative onto lithographic printing plates. Since 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.

Source: https://commons.wikimedia.org/wiki/Category:Switzerland_on_photochrome_prints