We apply Equation to predict the etching resolution as demonstrated experimentally in previous works of Schuster et al. , Kock et al. , and De Abril et al. , where different metal systems (Cu, Ni), electrolyte concentrations (1-200 mM), pH (1-3), and pulse heights (1.6-3.2 V) are used. Since Equation yields the spatial extent of interface charging sufficient for the etching reaction, and not the rate, these works are considered as they report the achieved resolution for long machining times. These processes are therefore expected to be complete, so that longer machining times will not result in further etching, and the resulting features indicate the maximum spatial extent of the confined etching.