A freestanding transmission grating has been used as a dispersive element in a simple monochromator. The monochromator, to be used with the collimated light beam from a resonance lamp radiation source, has been tested in the far uv with the helium and neon emission spectra. The results show that the simple monochromator will resolve all major lines in the emission spectra. A high efficiency into first‐order diffracted beams is obtained, and the efficiency is independent of photon energy. The results show that the resonance lamp–transmission grating combination is a unique source of monochromatic light for photoemission and optical work in the far uv region. More advanced monochromator designs and the possibility of extension of the monochromator for use at x‐ray energies are discussed.