GB561203A - Improvements in and relating to photographic developers and methods of producing photographic images by development - Google Patents

Abstract

561,203. Photographic developers. KODAK, Ltd. (Eastman Kodak Co., Dearing, L. M., and Guell, C. H.). June 25, 1942, No. 8753. [Class 98 (ii)] A photographic developer contains a developing agent and an aliphatic amine having an unsubstituted alkyl, alkenyl, or alkylene group which has from 3 to 7 carbon atoms in its molecule, the pH of the developer and the concentration of the aliphatic amine being so adjusted together as not to cause detrimental fogging of unexposed silver salt in the time required for development of a latent image therein. The pH of the developer should be from 10 to 11.5. The developer may be a black-and-white developer, and may be used in the first development in the reversal process, or may contain a colour coupler. The developer gives rise to less change of colour balance, and gives improved resolving power and definition. Amines specified are allylamine, diallylamine, propylenediamine, n-propylamine, iso-propylamine, n-butylamine, di-n-butylamine, n-amylamine, and di-n-amylamine. Mixtures of amines (e.g. iso-propylamine and n-butylamine) and mixtures of an amine with other silver halide solvents (e.g. thiocyanate or ammonia) may be used. In example 1, a first developer for the reversal process comprises metol, hydroquinone, sodium sulphite, sodium carbonate, potassium bromide, 5-nitroindazole, and n-butylamine, the pH being adjusted to 10.5 by addition of sodium hydroxide solution. In example 2, the developer comprises metol, hydroquinone, sodium sulphite, sodium carbonate, potassium bromide, and iso-propylamine. In example 3, a colour developer comprises diethyl-p-phenylenediamine hydrochloride, sodium sulphite, sodium carbonate, propylene diamine, o-phenylphenol, and sodium hydroxide.