Unless chemically brightened or mechanically pre-treated, all anodized surfaces have a satin matte appearance.

(1) Natural

This is a transparent anodic oxide film that reveals the silver sheen of the underlying metal. It is achieved by omitting the coloring stage in the process sequence and performing anodization directly.

Anodizing

(2) Electro-coloring Produces a wide range of colors from light bronze to black. This is accomplished by depositing cobalt or tin at the bottom of the pores within the anodic film. The color results from optical effects; for example, cobalt absorbs the blue component of light incident on the surface, causing bronze to be reflected. Since the color is obtained via optical effects dependent on particle size, it is completely fade-resistant.

(3) Interference

This provides the most practical spectrum of steel-blue and grey shades. It results from light interference caused by nickel at the bottom of enlarged pores in the anodic film. Again, since the color arises from optical effects dependent on particle size, it is completely fade-resistant.

(4) Combination

Bronze shades are combined with lightfast organic dyes to achieve various blues, reds, turquoises, greens, and oranges. Combination coloring is fade-resistant, though not completely non-fading.