Abstract: This invention relates to an improvement in a light-sensitive copying material, the copying layer of which comprises a water-soluble, curable binder and a diazonium salt polycondensation product of recurring units of the general types (A-N.sub.2 X) and (B) which are linked to one another by intermediate members which have two bonds and are derived from a carbonyl compound capable of undergoing a condensation reaction, wherein A is the radical of a compound which contains at least two isocyclic or heterocyclic aromatic rings and is able to undergo a condensation reaction, at least at one point in the molecule, with formaldehyde in an acid medium, B is the radical of a compound which is free of diazonium groups and is able to undergo a condensation reaction, at least at one point in the molecule, with formaldehyde in an acid medium, and X is the anion of an acid which forms a water-soluble salt with the condensation product, the improvement being that fish glue is the water-soluble, curable binder.