A significantly higher number of peaks was reached at Plangraph 1 in the Cap (-) modus at a roughness Ra of 3.02μ with 104/cm. With the hollow copper electrodes there was determined a peak count of only 63/cm at mode Cap (-) and almost the same roughness of 3.06μ Ra. Also with hollow copper electrodes at mode Puls (+) with almost the same roughness of 3,06µ Ra, there was a peak count of 76/cm. Further, the Plangraph 2 electrodes showed a slight increase in the number of peaks of 120/cm.