The authors demonstrate that it is possible to anodize steel in either KOH or NaOH solutions and grow an adherent oxide on the steel surface. By varying the temperature, voltage, and electrolyte composition, one may electrochemically grow either an adherent blue-black magnetite layer, a light brown oxide, or a semiadherent dichroic magnetite layer on many different types of steel. The dichroic oxide layers exhibit the different colors of the rainbow depending on the thickness of the layer and the viewing angle. The color is a function of the optical interference for the thin coatings. By selecting a narrow range of temperature, voltage, and electrode spacing, the adherent, blue-black magnetite layer can be grown several microns thick on some carbon steels. These anodized oxides provide corrosion protection and they are also a suitable substrate for bonding organic coatings.