We measure film thickness and surface dimensional changes using the mil, which is 0.001 inch or 25.4 microns.
Type II is often called "decorative anodizing." Sapphire Metal Finishing targets a thickness of 0.6 mils on all of our Type II films. At this thickness, dyed films are more resistant to fading and more durable than the thinner Type IIB films.
Type IIB is a thin decorative finish, usually 0.25 mils. This film is best for indoor applications, as it is less fade-resistant when dyed and less durable than Type II. Type IIB is strongly recommended for all 2024 clear finishes.
Type III is a true hard finish, used when an abrasion resistant film is desired. We anodize the aluminum at a low temperature and grow it to thicknesses of 0.5, 1.0, 1.5, and 2.0 mils. The color of Type III can vary and is affected significantly by the aluminum alloy being anodized and the thickness of the film. All alloys dye black very nicely.