Improvements in Photographic Printing

• Main Author: THOMAS MANLY
• Format: Patent
• Language: English
• Published: 31.05.1906

17,007. Manly, T. Aug. 22. Chromo-gelatinprocesses; printing; photo-mechanical printing.-Relates to the production of pigment prints from developed silver prints, either upon the silver print itself as a support, or by causing a pigmented film to take an impression of the silver print and transferring the pigment print to another support. The method employed in the latter case is applicable for collotype negatives. The pigmenting-bath used contains potassium or other alkali bichromate, ferricyanide, and bromide or chloride, together with aluminium alum and citric acid. The silver print and sensitized tissue are squeezed together and kept between blotting- paper for 20 or 30 minutes until ready for development. When the silver print is to support the pigment print, it is. developed with hot water and the original support stripped. Otherwise, they are plunged into cold water and separated again, and the pigment print developed and transferred to another support. The silver print in this case can be washed and re-developed and used again. Alternatively, when the silver print is used as a support, it may be directly coated with a pigmented film using the above sensitizing-bath.