Abstract: Capacitor foil includes a core layer, at least one porous layer and a porous surface layer, and a method for producing the same and an electrolytic capacitor. The at least one porous layer and the porous surface layer are porous as a result of a first DC-pulse etching process step. The method includes at least one further etching step in which the etching fluid of the first etching process step in the at least one porous layer and the porous surface layer is modified into or replaced by a filling substance having a low etching capability, at least the porous surface layer of the foil is further etched to increase the porosity of the porous surface layer, and the filling substance is removed from the foil.