GB269912A - Improvements in the manufacture of photographic negatives and prints - Google Patents

Abstract

269,912. Klaver, L. April 21. 1926, [Convention date]. Films and papers, stripping; colour photography. -To facilitate stripping, there is interposed be. tween the sensitive layer, which is preferably unhardened, and its liquid-pervious support a layer of casein which is readily soluble without heating in dilute ammonia solution without injury to the sensitive layer. The support may consist of black or dark red paper. Three-colour prints may be produced by applying a piece of sensitive material to glass or celluloid coated with wax, printing for example from the blue-record negative through the glass or celluloid, stripping the original paper support after wetting its back with a half per cent solution of ammonia, and developing, colouring, and hardening the image layer. After registering the print so produced in the printing-frame with the red-record negative, the print is removed and a fresh piece of sensitive transfer material is applied to it without previous waxing, whereafter the print is restored to its registered position in the frame, and the red record is printed through the glass or celluloid, developed, coloured, and hardened as before. The yellow image is superimposed in the same manner as the red. The completed picture is finally transferred from the glass or celluloid to paper. Relief images may be produced by development with a tanning developer followed by etching away of the soft gelatin. The sensitive layer may, if desired, be ready-coloured.