GB766101A - Improvements in photographic developer compositions - Google Patents

Abstract

766,101. Photographic developers. KODAK, Ltd. March 23, 1955 [April 1, 1954], No. 8457/55. Class 98(2) A single-powder photographic developer composition comprises an organic silver halide developing agent, lithium hydroxide monohydrate containing exactly 1 mole of water of crystallization, and a stabilizing agent such as boric, phthalic orchlorophthalic anhydride, metaboric acid, or sodium or potassium bisulphite or metabisulphite or a mixture of two or more of these. A preservative such as sodium sulphite and a restrainer such as potassium bromide may be added. Examples are given of compositions containing (1) N- monomethyl - p - aminophenol sulphate (metol), hydroquinone, sodium sulphite, sodium carbonate monohydrate, potassium bromide, lithium hydroxide monohydrate, and boric anhydride; (2) metol, hydroquinone, sodium sulphite, sodium metaborate trihydrate (CO 2 treated) potassium bromide, lithium hydroxide monohydrate, boric anhydride, and sodium metabisulphite; (3) as (2) using sodium metaborate tetrahydrate containing 10 per cent boric anhydride and using phthalic instead of boric anhydride; (4) as (3) using sodium metaborate tetrahydrate containing 10 per cent metaboric acid; (5) as (2) using anhydrous sodium tetraborate and no sodium metabisulphite; (6) hydroquinone, sodium sulphite, lithium hydroxide monohydrate, potassium bromide, and boric anhydride; and (7) as (5) using sodium tetraborate pentahydrate. Specifications 698,311 and 725,892 are referred to.