Abstract: A photopolymerizable composition having improved thermal stability comprising (a) a polymerizable ethylenically unsaturated monomer, (b) an initiator represented by the general formula (I): ##STR1## wherein Z represents the non-metallic atoms necessary to complete a nitrogen-containing heterocyclic nucleus; R.sup.1 represents an unsubstituted or substituted alkyl group; and R.sup.2 represents an unsubstituted or substituted alkyl group, an unsubstituted or substituted aryl group, or a thienyl group; and (c) a chlorinated polyolefin as a binder and additionally containing (d) about 1 to about 30% by weight of an epoxy compound.

Abstract: An image-wise light-sensitive composition containing (a) an organic polymer compound containing chlorine; (b) a coloring matter forming compound represented by the formula: ##STR1## wherein R.sup.1 through R.sup.4 each represent a hydrogen atom, an alkyl group, or an aryl group, and R.sup.5 to R.sup.6 each present a hydrogen atom, an alkyl group, or R.sup.5 and R.sup.6 can combine with each other to form a 5- or 6-membered carbon ring, and (c) a liquid capable of dissolving said organic polymer compound and coloring matter-forming compound.

Abstract: A presensitized lithoprinting plate which needs no fountain solution on printing comprising a support and a coating layer of a mixture of a photosensitive material and a silicone rubber.

Abstract: A dry presensitized planographic plate composed of a support having coated thereon one or two layers of (a) a silicone rubber, (b) a photosensitive azide compound, (c) a cyclized rubber, and (d) a copolymer of vinylidene chloride and acrylonitrile, the uppermost layer, when the planographic plate has two layers, containing at least the component (a) and (b) and the lower layer containing at least the component (c).

Abstract: A presensitized planographic printing plate which can be used in both negative and positive work comprising a support, a layer formed on the support of a photosensitive substance prepared by the reaction at a pH of not more than 7.5 of a diazonium compound with a coupling agent, e.g., hydroxybenzophenone, and a layer formed on the photosensitive layer of a "one-package" silicone rubber curable at room temperature. A planographic printing plate per se is produced by imagewise exposing the presensitized plate through a negative or positive film, and treating the exposed plate with a treating liquid capable of removing those portions of the presensitized plate which correspond to the image area of the original. Dampening water is not required when printing is carried out using the resulting printing plate.