Abstract: A method of increasing the strength, abrasion resistance, solvent resistance, and press life of a lithographic image comprising a layer of light-reacted light sensitive material and an outer layer comprising an epoxy resin overlying the light-reacted layer. In the method, the surface of the outer layer is contacted and wetted with an aqueous solution comprising a least about 7% by weight of a boron trifluoride-amine complex. Solvent is evaporated from the solution on the surface to deposit dry boron trifluoride-amine complex on the outer layer and the outer layer is heated in the presence of the complex to cross-link the epoxy resin and form a hard, tough, abrasion-resistant, solvent-resistant and wear-resistant epoxy resin layer at the outside of the image. Further included in the invention are a curing composition adapted for topical application to a lithographic image in carrying out the method of the invention and a planographic printing plate produced thereby.