Silver films are deposited on a SiO2 surface and a cyclo-olefin polymer surface by radio frequency and direct current (RF–DC) coupled magnetron sputtering to realize light reflectors with high reflectivity in the visible light region. Because the reflectivity of silver is relatively low, especially in the short-wavelength region less than 500 nm owing to a slight increase in the refractive index of silver, deposition conditions are studied with emphasis on maximizing the reflectivity in this region. Also, protection film depositions of Si3N4 on a silver surface by microwave-excited-plasma-enhanced chemical vapor deposition were carried out to improve the durability of silver films, which are easily oxidized and/or sulfurized, resulting in the degradation of the reflectivity of the films. It is found that a high reflectivity in the short-wavelength region can be obtained by Xe plasma sputtering and/or Ar plasma sputtering at a relatively high working pressure, i.e., the conditions with a low ion bombardment energy at the substrate surface. At the same time, a normalized ion flux supplied to the substrate surface at approximately 2 is optimum, where the normalized ion flux is defined as the ratio of plasma-ion flux to deposited-atom flux on the growing film surface. Under such optimized deposition conditions, a silver film with a low resistivity and a smooth surface is obtained. Furthermore, it is found that a Si3N4 film with a thickness of 8 nm on a silver surface serves as a good protection film without serious degradation of reflectivity, and the reflectivity can be maintained even after the immersion of the sample in the boiling water (100 °C) for 2 h.