REVEALING MIXTURE AND PROCESS FOR THE REVELATION OF PHOTOSENSITIVE COPIER LAYERS EXPOSED TO LIGHT

摘要

This invention relates to a developer mixture for washing out light-sensitive copying layers previously exposed in imagewise manner and containing a polymer of an N-vinyl amine, of vinyl alcohol or of a vinyl alcohol derivative, an alcohol being water-soluble in an amount less than 10% by weight, and water as the main constituent, the mixture containing as said polymer a copolymer which is water-soluble or which can be dispersed in water to form a stable dispersion, composed of (a) hydrophilic units of the formula I: IMAGE wherein A is O-R or IMAGE R is a hydrogen atom or a methyl group; R1 is a hydrogen atom, an alkyl group or an alkoxy alkyl group having 1 to 10 carbon atoms each or an aryl group with 6 to 10 carbon atoms; R2 is an alkyl group or an acyl group having 1 to 5 carbon atoms each, and wherein a homopolymer of the hydrophilic units is water-soluble and of (b) hydrophobic units of vinyl monomers whose homopolymer is water-insoluble and which have an aromatic or a long-chain aliphatic group as the substituent, the proportion of the hydrophobic units being sufficient to ensure that an 0.1% aqueous solution of said copolymer has a surface tension of not more than 50 mN/m and that the quantity of said copolymer is at least sufficient to emulsify any quantity of alcohol exceeding the solubility limit. The invention also relates to a process for developing exposed light-sensitive copying layers using said developer mixture.