Abstract
A study is made of the mechanisms affecting the spectral absorption in anodic copper oxide films. It is shown that the solar absorption is due to the unique surface structure of the anodic oxide film in combination with the optical properties of the basic film component, CuO. The surface structure also affects the spectral absorption in the 4–10 micron region contributing to the thermal emittance. Changing the ratio of CuO/Cu2O in the bulk film composition has a minor effect on the thermal emittance for emittance values of less than 0.10.