In order to increase the corrosion resistance and to obtain a decorative effect, the oxide layer of aluminium and its alloys can be intensified by chemical and electrochemical processes. This oxide layer is colored, using different procedures, in order to obtain a decorative effect. The demand on colored oxide layers in the architecture and the automobile industry is that they be light fastness and resistant to weathering and provide a sufficient corrosion protection of the layers. If aluminium oxide layers can fulfil these requirements, this would contribute to making colored oxide layers attractive again for the market. Above all, by an attractive coloring, the acceptance and the sales of aluminium products would increase. By this means, the business results of the branch can be favorably influenced, especially the competitivity with regard to countries having low wages. The testing of the procedures ensues in laboratory and field experiments. A coloring procedure which meets the demands of the market would mean a considerable advantage in competition for the small and medium-sized enterprises within Europe. The results will be carried over into the elaboration of new regulations and into the revisions of national and international norms.