Abstract: A system for anodizing aluminum wherein an aluminum web is positively charged predominantly on a first surface thereof, subsequently immersed in an electrolyte having a cathode therein, and thereafter a current is passed through the electrolyte between the cathode and a second surface of the aluminum opposite to the first surface. The foregoing is accomplished by an apparatus having an anode in a contact cell disposed parallel to the first surface of the aluminum web and cathodes in an anodizing cell disposed predominantly adjacent the second surface of the aluminum web. The anodized coating deposited on the second surface of the web is sealed by a cold water spray.