Ag and Cu interfaces with chemically prepared CdS surfaces have been studied under hydrostatic pressures to 10 kbar. These interfaces exhibit a photovoltaic spectrum at photon energies less thanEgdue to the existence of new states bound at the interface. We find that the pressure coefficient of the interface‐state subband is sensitive to the preparation of the interface even through the atmospheric pressure photovoltaic spectra of the various interfaces studies are very similar.