Planographic printing plate method using light sensitive material including phenolic resol with dibenzylic ether groups

A method for making a planographic printing plate, which comprises (a) image-wise exposing a light-sensitive material with actinic radiation, said light-sensitive material being in the form of a layer on a hydrophilic surface of a substrate thereby enabling a planographic printing plate to be obtained and including a light-sensitive composition comprising (i) a phenolic resol wherein the ratio of the number of dibenzylic ether linkages to the total number of dibenzylic ether, methylene and methylol linkages linked to phenolic nucleus is 15 mol.% or more and which phenolic resol is obtained by a reaction between at least one phenol of the formula (I):

• ##STR3## wherein R.sub.1, R.sub.2 and R.sub.3 may be the same or different and represent a hydrogen, halogen, hydroxyl, nitro, alkyl having 1 to 20 carbon atoms, alkoxy having 1 to 20 carbon atoms, phenyl having 6 to 20 carbon atoms, or substituted phenyl having 6 to 20 carbon atoms, and an aldehyde and/or ketone under neutral or weakly acidic conditions and subsequent removal of water, and (ii) at least one member selected from the group consisting of diazo resins, o-quinone diazide compounds, light-sensitive azide compounds, high molecular compounds having a --CH.dbd.CH--CO-- group in the main or side chain thereof, addition-polymerizable unsaturated compounds and acid-decomposition compounds, and wherein ingredients (i) and (ii) are together in admixture or as a light-sensitive esterified reaction product of the phenolic resol with o-quinone diazide sulfonyl halide,
• (b) developing the resulting exposed material to form a printing plate image, and
• (c) heating the resulting developed material to a temperature of not less than 140.degree. C. to increase printing durability.