A visual prosthesis must convey luminance information across a range of brightness levels to accurately represent a visual scene. Thus, the brightness of phosphenes produced by individual electrodes should scale appropriately with luminance, and the same luminance should produce equivalently bright phosphenes across the entire electrode array. Given that the function relating current to brightness varies across electrodes, it is necessary to develop a fitting procedure that will permit brightness to be equated across an entire array. A visual prosthesis that generates stimuli by performing a brightness fitting that normalizes brightness across electrodes is described.