GB515674A - Method of making coloured pictures from photographs - Google Patents

Abstract

515,674. Photographic colouring and toning processes. GUDENBERG, W. A. VON. March 2, 1938, No. 6625. Void. Convention date, March 2, 1937. [Class 98 (ii)] Consists in methods of locally toning or colouring black and white photographs on paper, glass, or other supports. The chemicals or colours may be applied by a brush or a cotton wool pad, and a removable varnish margin may first be, applied round the part to be treated to protect the remaining parts. Alternatively, a plastic rim as of putty may be applied round the part to be treated to form a dish into which the chemicals or colouring solution is poured, and if desired a varnish margin may be applied before applying the plastic rim. In another method, the photograph is given a ground colour by general chemical toning, and parts are then coloured by local application of tints. Particular toning processes mentioned are the ordinary sulphide sepia process with preliminary ferricyanide bleach; a modification in which the sulphide toning is followed by gold toning : and a further modification in which the photograph is first slightly bleached all over .with ferricyanide, locally re-developed at parts which are to remain uncoloured or are to be coloured or toned subsequently and then toned with sulphide at the remaining parts.