This final report contains three principal items. The first describes a simple and novel reflectometer which can separately evaluate the spectral and diffuse reflectivities of surfaces. A phase locked detection system for the reflectometer is also described. The second item is a selective coating on aluminium potentially useful for flat-plate solar collector applications. The coating is composed of strongly bound copper oxide (divalent) and is formed by an etching process performed on an aluminium alloy with high copper content. Because of this one step fabrication process, fabrication costs are expected to be small. Process parameters, however, need further definition. The third item contains conclusions gleaned from the literature as to the required optical properties of flat plate solar collectors.