GB229568A - Improvements in re-enforced hosiery - Google Patents

Abstract

229,568. Jelley, E. E. July 22, 1924. Plates and films; printing paper, fabrics, and materials; developing; toning. - A sensitizer which may be stored and applied when required to surfaces such as paper, parchment, plaster, textile fabrics, or films such as of casein, gelatine, or albumen, which contain or have added thereto traces of halogen salts, consists of a mixture containing a soluble silver salt and one or more soluble salts of hydrazine and/or its derivatives. Several silver salts and salts of hydrazine. and its derivatives are instanced. The silver and hydrazine salts may be kept in the dry state in the required portions, separate or mixed, either loose or in tablets, so that it is only necessary to aid the required amount of water to form the sensitizer, or in solution, the sensitizing solution containing from per cent up to saturation of each of the salts. The solution is applied to any absorbent surface or to a non-absorbent surface. such as glass, porcelain, or plaster to which an absorbent layer, for example of casein, gelatine, or albumen has been added, the surface being free from reducing, oxidizing, alkaline, or sulphide compounds. Surfaces which do not contain halogen salts may first be treated with a solution for example of sodium chloride, or potassium bromide. The surfaces may be used for printing as with either self-toning or gaslight papers. When a short exposure is given the image may be developed in an alkaline solution containing for example sodium chloride and hydroxide, or di-sodium hydrogen phosphate and sodium carbonate, or certain salts of weak acids such as sodium acetate used in hot aqueous solution. The print may be toned in shades between brown and prussian blue by a solution containing potassium ferrocvanide, iron alum, and nitric acid. Copper ferricyanide and uranium ferricyanide solutions may be used for toning up to chalky red tones. Black or grey tones are obtained by bleaching with mercuric chloride and hydrochloric acid, washing, and immersing in a 5 per cent solution of sodium sulphite. The print may also be dye-toned by any of the processes used with bromide papers.