The electronic band structures of some rare earth metals have been investigated by optical reflection spectroscopy. Newly developed optimization methods have been used on specimens produced in vacuo and measured by means of a reflectometer constructed in laboratory. Optical properties of these rare earth films have also been studied as a function of ageing. The results have been compared with a model based on the growth of dielectric layers on the film surface. The electronic band structure of iron has also been investigated by observing and measuring optical and magneto-optical properties.