Coating media and their use in processes for producing single-layer and multi-layer coatings are described. The coating media contain an aqueous mixture comprisingI. 99-70% by weight of a mixture ofA) 50-100% by weight of one or more binder vehicles which at least in part contain ionic groups,B) 0-50% by weight of one or more crosslinking agents, which at least in part may contain ionic groups, for binder vehicle A), wherein the ionic groups which are present have the same charge as those of component A), andII. 1-30% by weight of one or more binder vehicles (component C), which are miscible both with the binder vehicles of component A) at the storage temperature and with each other at the curing temperature of the coating media and which contain ionic groups, the charge of which is opposite to the charge of the ionic groups of component I), wherein the percentages by weight are given with respect to the weight of resin solids in each case and wherein the proportions of components I) and II) are matched to each other so that 0.5 to 70% of the number of charges of the ionic groups of I) are neutralised by the charges of the ionic groups of II), andIII. customary lacquer additives and/or pigments and/or extenders, and optionally one or more customary lacquer solvents.