GB548347A - Improvements relating to photographic materials - Google Patents

Abstract

548,347. Photographic emulsions. KODAK, Ltd. March 3, 1941, No. 2878. Convention date, March 2, 1940. [Class 98 (ii)] A spreading-agent for incorporation in a sensitive emulsion or in any other predominantly aqueous solution of gelatine or other hydrophilic colloid to be applied to a photographic support comprises an ether of the formula where R<SP>1</SP> is the hydrocarbon radical of a polyhydric alcohol of at least three hydroxyl groups, n and p are integers whose sum equals the number of hydroxyl groups of the polyhydric alcohol, and each R is an aliphatic alkyl or acyl radical containing from 8 to 18 carbon atoms or an alicyclic alkyl or alicyclic acyl radical. From 0.002 to 0.2 per cent of the ether (by weight) may be present in the sensitive emulsion of other solution. R<SP>1</SP> may be the residue of glycerol, pentaerythritol, sorbitol, or mannitol, and R may be lauryl, lauroyl, oleyl, oleoyl, naphthenyl, abietyl, hydroabietyl, naphthenoyl, abietoyl or hydroabietoyl. An example is 1 : 2 : 3 : 4 : 5-penta- #-hydroxyethoxy-6-#-lauryloxyethoxyhexane. The sensitive emulsion or other solution containing the ether may be applied to the support and set by chilling, and before drying, a predominantly aqueous solution of gelatine or other hydrophilic colloid may be applied over the layer produced. If more than one predominantly aqueous solution of gelatine or other hydrophilic colloid is applied to the support, any or all of the layers may contain the ether. The incorporation of the ether may also improve the ageing qualities of the emulsion, increase its speed, and reduce storage fog. The emulsions are also more readily wetted by developing solutions. Other hydrophilic colloids referred to are watersoluble cellulose derivatives such as well-hydrolysed cellulose acetate, cellulose esters of lactic, glycollic, and other hydroxy-monocarboxylic acids and salts of cellulose esters of dicarboxylic acids such as phthalic acid ; polyvinyl alcohol such as hydrolysed polyvinyl acetate, and water-soluble polyvinyl acetals. Specifications 531,579, 542,703 and 542,704 are referred to.