Abstract: A passthrough method is provided in which the surface of an industrial grade, low-grease precursor made of copper, with a defined surface roughness, is patinated. For this purpose the precursor material, connected as the anode, is passed through an electrolysis bath, containing sodium carbonate and/or sodium hydrogencarbonate as well as sodium sulfite and/or sodium disulfite, with a temperature of 30.degree. C. to 90.degree. C. and a current density of 1 A/dm.sup.2 to 20 A/dm.sup.2 as bath parameters, for a residence time of 10 seconds to 12 minutes. The precursor material is rinsed and then moved through a fixing bath at a temperature of 35.degree. C. to 95.degree. C. for a residence time of 10 seconds to 120 seconds, and lastly, after a further rinsing, is dried. The fixing bath contains at least one of the oxidation agents: hydrogen peroxide (H.sub.2 O.sub.2), potassium chlorate (KClO.sub.3), potassium peroxodisulfate (K.sub.2 S.sub.2 O.sub.8), potassium permanganate (KMnO.sub.4), of copper sulfate (CuSO.