Process for continuous electrolytic coloring of aluminum or aluminum base alloy strip and wire

In a process for electrolytically coloring an anodically oxidized aluminum or aluminum base alloy strip or wire as a cathode in a coloring bath comprising an aqueous solution containing at least one nickel salt, cobalt salt, tin salt, iron salt, copper salt or selenious acid while continuously travelling said anodically oxidized aluminum or aluminum base allow strip or wire, the improvement which comprises subjecting said anodically oxidized aluminum or aluminum base alloy strip or wire as a cathode to direct current electrolysis using an electrolytic coloring means comprising at least one hollow body which has an anode therein, said anode being insulated from said hollow body, and has an opening of slit shape for continuously and uniformly supplying the coloring bath onto at least one surface of said strip or wire, the longitudinal direction of the slit being perpendicular to the direction of travel of said strip or wire in order that the coloring rate of said strip or wire becomes a maximum value at the portions in the vicinity of said hollow body, while continuously supplying said coloring bath onto at least one surface of said aluminum or aluminum base alloy strip or wire.