GB694562A - - Google Patents

Abstract

694,562. Photographic oxidizer-modifiers. RUBINSTEIN, L. April 11, 1949, No. 9807/49. Class 98 (ii). An aqueous solution of a halogen containing a water-soluble aliphatic aldehyde or ketone which is non-destructive of gelatin and is present in a proportion by weight at least equal to that of the halogen is applied to all or part of a developed negative or positive photographic image to adjust the image clarity and intensity thereof. An acid, and sugar or salt or both of these may be included in the solution. The first of numerous examples of the oxidizer-modifiers comprises " concentrated iodine " 1 dram, " decolorized iodine N.F. VI " 3 drams, formalin 1 dram, hydrochloric or sulphuric or nitric acid 1 dram, common salt or sugar 2 oz. and distilled water 16 liquid oz.; of which the " concentrated iodine " is prepared by dissolving 1 ounce of potassium iodide in 3 ounces of water and saturating this with iodine, and the " decolorized iodine N.F. VI " is prepared by adding 100 c.c. of 37 per cent ammonia to a solution comprising 25 grams potassium iodide, 50 grams iodine, 400 c.c. water and 400 c.c. alcohol, allowing the mixture to stand until it becomes colourless and then adding alcohol to a volume of 1000 c.c. Various methods of application of the oxidizer modifiers to photographic images, including colour records and colour transparencies, are described. In the case of retouching parts not to be treated may be protected by a resist such as a composition comprising beeswax 1 gram, lanolin 2 grams and " white petrolatum " between 12 and 15 grams.