Abstract: A water soluble diazonium salt composition made by the condensation of diazoaryl amines and aldehydes and precipitated to form a polymeric anionic species having both ZnCl.sub.4.sup.= and HSO.sub.4.sup.- moieties. These composition are blended with suitable binders, colorants and other optional components to produce light sensitive coating compositions. When applied to aluminum substrates, these light sensitive coating compositions form lithographic printing plates that are especially stable under high humidity conditions. Such plates may be developed by either water alone or by water which contains surfactants and/or a small amount of an organic solvent.