Carbon process

Printing process in which powdered carbon is used as a pigment to form an image, particularly when the process employs sensitized carbon tissue on gelatin. The process was patented by Joseph Wilson Swan in 1864, his work having been base on the work of A. L. Poitevin; it was actively exploited in England by the Autotype Company, who acquired Swan's patent rights in 1868. The process depends upon the hardening action of light on bichromated gelatin, whereby sheets of pigmented gelatin are used to transfer images to a paper support.