Increases in surface reaction rates caused by periodic illumination of iron and nickel passive films with polychromatic and monochromatic light have been measured. The electrode photoresponse is caused by excitation of a surface film which is the product of anodic oxidation. The dependence of the photo‐current magnitude on electrode potential and excitation energy suggests that the passive layers possess semiconductor characteristics. Capacitance and kinetic measurements are reported which support a proposed model.