A method for designing efficient chromatography processes was proposed and verified experimentally. The model samples were polyphenols. Polystyrene divinylbenzene resins were employed for the column stationary phase. The mobile phase was an ethanol-water mixture. The distribution coefficient, K, was determined as a function of ethanol concentration, I, by linear gradient elution experiments. The HETP-mobile phase velocity (u) curves were determined as a function of I. A method for calculating the iso-resolution curve was developed with K and HETP-u as a function of I. The calculated iso-resolution curve was verified by comparison with experimental elution curves. The iso-resolution curve was found to be useful for determining suitable separation conditions.