Abstract: The present invention provides a photosensitive composition comprising an infrared absorbing agent represented by the following formula (I) and a polymer compound which is insoluble in water and soluble in an aqueous alkali solution and becoming soluble in an aqueous alkali solution by radiation of an infrared laser. In the formula described below, R1 and R2 independently represent an alkyl group having 1 to 18 carbon atoms or an alkyl group having 9 to 30 carbon atoms and Z represents a heptamethine group which may have a substituent. The definitions of other substituents are shown in the specification. According to the present invention, a photosensitive composition having high development latitude and storage stability, together with a positive type planographic printing plate for direct plate-making which can form an image with high sensitivity by using an infrared laser, are provided.

Abstract: The present invention provides a photosensitive composition comprising an infrared absorbing agent represented by the following formula (I) and a polymer compound which is insoluble in water and soluble in an aqueous alkali solution and becoming soluble in an aqueous alkali solution by radiation of an infrared laser. In the formula described below, R1 and R2 independently represent an alkyl group having 1 to 18 carbon atoms or an alkyl group having 9 to 30 carbon atoms and Z represents a heptamethine group which may have a substituent. The definitions of other substituents are shown in the specification. According to the present invention, a photosensitive composition having high development latitude and storage stability, together with a positive type planographic printing plate for direct plate-making which can form an image with high sensitivity by using an infrared laser, are provided.

Abstract: The present invention provides a photosensitive composition comprising an infrared absorbing agent represented by the following formula (I) and a polymer compound which is insoluble in water and soluble in an aqueous alkali solution and becoming soluble in an aqueous alkali solution by radiation of an infrared laser. In the formula described below, R1 and R2 independently represent an alkyl group having 1 to 18 carbon atoms or an alkyl group having 9 to 30 carbon atoms and Z represents a heptamethine group which may have a substituent. The definitions of other substituents are shown in the specification. According to the present invention, a photosensitive composition having high development latitude and storage stability, together with a positive type planographic printing plate for direct plate-making which can form an image with high sensitivity by using an infrared laser, are provided.

Abstract: A photopolymerizable composition is disclosed, comprising (i) a compound having at least one addition-polymerizable, ethylenically unsaturated bond; (ii) a compound represented by formula (IA) or (IB): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.9, R.sup.10, R.sup.11 and R.sup.12 each independently represents a hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, a hydroxyl group, a substituted oxy group, a mercapto group, a substituted thio group, an amino group, a substituted amino group, a substituted carbonyl group, a sulfo group, a sulfonato group, a substituted sulfinyl group, a substituted sulfonyl group, a phosphono group, a substituted phosphono group, a phosphonato group, a substituted phosphonato group, a cyano group or a nitro group or R.sup.1 and R.sup.2, R.sup.2 and R.sup.3, R.sup.3 and R.sup.4, R.sup.9 and R.sup.10, R.sup.10 and R.sup.11 or R.sup.11 and R.sup.