In the same year, M. Lafon de Camarsac announced his discovery[1] of methods of producing photographs in enamel colors, in which, although very vaguely stated, are involved the elements of a carbon process.
In 1857, Dr. Phipson conceived that certain volatile oils, such as those contained in the oil known as huile de Dippel, or those which accompany naphthaline, and which blacken when exposed to the light and to the air, might be used to obtain photographs.
In September, 1857,[2] Mr. Thomas Sutton proposed adding the finest pulverized charcoal to an albuminous solution of bichromate, so as to form a black mixture of about the consistency of common shoe-blacking, which was then applied to paper. This was to be exposed under a negative, and the unaltered material subsequently removed by repeated washings, and a carbon print produced.
Later in 1857, M. Testud de Beauregard, a gentleman who had devoted much attention to the production of photographs without salts of silver, patented a process, not differing from that of M. Poitevin in principle, but having some modifications in detail. In his specification he re-states the fact as already recognized, that if a mixture of gum or gelatine, bichromate of potash or ammonia, and an insoluble coloring matter, such as carbon, black-lead, vermilion, indigo, etc, be exposed to light, it is rendered insoluble, the coloring matter or pigment being imprisoned or retained by the mixture, and that if such exposure be effected under a negative, the portions not acted upon by light may be washed away, leaving an image in pigments.
Mr. Pouncy appears to have been the first in England
