We have measured the number of photons/cm2over the energy range 1.95 to 3.35 eV, required to form a negative‐relief image in 2000 A˚ films of As2S3using 100 A˚ films of evaporated Ag, Ag2Te, Ag2Se, and AgBr. We have observed sensitivity below the band gap of As2S3in all cases. We have observed an increase in sensitivity by several orders of magnitude with increase of photon energy between 1.95 and 3.35 eV. The sensitivity decreases from Ag to the semimetals Ag2Te and Ag2Se to the wide band gap AgBr by the ratio 1:50:2500 at 2.4 eV. Assuming an internal photoemission model as proposed by Goldschmidt and Rudman, we extract barrier heights of 1.71, 2.10, 2.22 and 2.42 eV for Ag, Ag2Te, Ag2Se, and AgBr.