the cell and an alternating current voltage is applied between an electrode plate 5 disposed within an electrolytic coloring cell 4 and the electricity supply element 3 a strip wire or foil 6 hereinafter referred to as 34 strip 34 of aluminum or an alloy thereof wound on an uncoiler not shown is unwound and the strip is subjected to a pretreatment comprising degreasing washing with water etching washing with water neutralization and washing with water the strip thus pre treated is contacted with the supply element 3 to charge it positively and the charged strip is passed through the cell 1 at any appropriate rate to anodize it the anodized strip is then passed through the cell 4 to color it thereafter the colored strip is washed with water and wound up on a recoiler not shown the following examples will further illustrate the first example as described above of the process of the present invention an aluminum alloy 5005 h14 was anodized at a rate of 4 m min in a sulfuric acid solution having a concentration of 300 g per liter in the electrolytic cell 1 including an electrode plate 2 made of lead the temperature of the solution was 30 u00b0 c and the direct current voltage applied was 20 v then the anodized alloy was electrolytically colored in the electrolytic cell 4 containing 2 g l stannous sulfate 20 g l nickel sulfate 10 g l sulfuric acid and 5 g l cresol sulfonate and including an electrode plate 5 made of nickel the temperature of.