Photochrom prints, also called Aäc, are ink-based images produced through "the direct photographic transfer of an original negative onto litho and chromographic printing plates." Hans Jakob Schmid (1856-1924), who worked for the Swiss firm Orell Füssli, invented the technique in the 1880s.
These postcards of the ancient landmarks of Rome were produced around 1890 using the Photochrom process, which add precise gradations of artificial color to black and white photos.
(Photos via The Library of Congress)
These postcards of the ancient landmarks of Rome were produced around 1890 using the Photochrom process, which add precise gradations of artificial color to black and white photos.
(Photos via The Library of Congress)