Abstract: The invention relates to a recording material for the production of an offset printing plate, having a substrate on whose front a photosensitive image layer is present and on whose back a layer of an organic polymeric material having a glass transition temperature Tg of 45° C. or more is present. The photosensitive image layer, or any top layer present thereon, has a pigment layer formed thereon.

Abstract: A radiation sensitive material comprises particles including a water-insoluble heat-softenable core surrounded by a shell which is soluble or swellable in aqueous medium. The material also includes a radiation sensitive component which, on exposure to radiation, causes the solubility characteristics of the material to change. The material may be positive- or negative-working and may be coated onto a substrate from aqueous media to form a radiation sensitive plate which, after image-wise exposure, can be developed in aqueous media and then heated to cause the particles to coalesce and form a durable printing image.

Abstract: A radiation sensitive material comprises particles including a water-insoluble heat-softenable core surrounded by a shell which is soluble or swellable in aqueous medium. The material also includes a radiation sensitive component which, on exposure to radiation, causes the solubility characteristics of the material to change. The material may be positive- or negative-working and may be coated onto a substrate from aqueous media to form a radiation sensitive plate which, after image-wise exposure, can be developed in aqueous media and then heated to cause the particles to coalesce and form a durable printing image.

Abstract: A radiation sensitive compound contains at least two groups having the structure ##STR1## in which Ar represents a divalent or other polyvalent radical derived from an aromatic or heteroaromatic compound; X and X' which may be the same or different, each represents O, S or an imino group, provided that at least one of X and X' is an imino group; Y represents O or S; R represents a single bond or a divalent or other polyvalent radical and A.sup.- is an anion. Radiation sensitive compositions comprising the compound and optionally a resin may be used to produce radiation sensitive plates for lithographic printing plate production.

Abstract: A photoconductive composition comprises a photoconductor and a sensitizer. The sensitizer has the formula ##STR1## wherein R represents alkyl; R1 represents H, alkyl or aryl; R2 represents the atoms required to complete a hetero or carboxyclic ring; A.sup.- represents an anion; and n represents the valency of the anion. The composition is sensitive to both laser light sources and tungsten light sources and is useful in electrophotographic reproduction.

Abstract: A positive working light-sensitive composition comprises in admixture (a) a first component which is an azo dye formed by reacting a p-amino-benzene diazonium salt and a compound including the grouping ##STR1## and (b) a second component which includes a o-quinone diazide and/or a diazonium compound and which, on exposure to light produces an acidic light decomposition product which is capable of reacting with the azo dye to produce a material having a color different to that of the azo dye. The composition exhibits a color change on exposure to light and is useful for the manufacture of light sensitive plates for use in lithographic printing plate production.

Abstract: A photopolymerizable material suitable for use in the production of lithographic printing plates comprises a polymer which includes a plurality of structural units represented by the Formula: ##STR1## in which R.sup.1 represents a hydrogen atom or a methyl group; R.sup.2 represents a hydrogen atom, an alkyl or substituted alkyl group, an aryl or substituted aryl group, or a heterocyclic or substituted heterocyclic group; R.sup.3, R.sup.4 and R.sup.5, which may be the same or different, each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an aralkyl group, an aralkoxy group or an alkoxy carbonyl group; Z represents a hydroxyl group, or an ester group and a is an integer greater than or equal to 1.

Abstract: A light sensitive material suitable for coating onto a support to produce a light sensitive plate for use in, for example, the manufacture of a printing plate comprises groups of the formula: ##STR1## attached to carbon atoms, wherein ##STR2## wherein R.sub.5 represents a hydrogen atom or an alkyl group; R is an aromatic radical; a is zero or unity; R.sub.1, R.sub.2 and R.sub.3 are hydrogen atoms, halogen atoms, cyano groups, or specified aliphatic or aromatic groups; X is a deactivating group; R.sub.4 is a hydrogen atom, a carboxyl group, a cyano group or a specified aliphatic or aromatic group; and Ph is a phenyl group. The material may be produced by reacting a polymer containing epoxide groups, hydroxyl groups, or primary and/or secondary amino groups with the halosulphonyl group of a compound having the forula: ##STR3## wherein R, R.sub.1, R.sub.2 R.sub.3, and a have the above meanings, wherein X has the above meaning or is a halosulphonyl group and R.sub.