Wonderful New Photographic Process.

Progress, Volume I, Issue 7, 1 May 1906, Page 173

Wonderful New Photographic Process.

The interesting catalytic process called the " Catatype Process " was devised by Professor Ostwald and Dr. Gros. It is concerned with the making of photographic prints without sunlight. Since, thanks to Dr. Gros, the writer was made practically acquainted with this process at the works of the Neve Photographische Gesellschaft, at Steglitz, the reader may try it for himself. We already know how easily peroxide of hydrogen decomposes in the mere presence of metals. This is here the primary fact. A piece of cotton is dipped into a mixture of peroxide and ether, and is then quickly rubbsd over the face of the negative. It is then left for a brief instant. ■ During this brief instant the ether evaporates, and wherever there is no silver the peroxide is catalysed by its presence into water, and wherever there is no silver the peroxide is left unaltered. There is thus on the face of the negative an invisible positive of peroxide. Place now the negative in contact with a piece of gelatinised paper in a " printing frame," and this invisible positive is at once transferred to the paper, and on placing'this paper immediately into an alkaline solution of manganous sulphate, for example, you will obtain a beautiful picture in brown tones. With an alkaline silver solution the print will be black. The process is peculiarly applicable for the easy production of beautiful " carbon " prints. The pigmented and unsensitised paper is brought into contact, as described above, and is then treated in the ordinary way.