How to Specify

The Aluminum Association Designation System for Anodized Aluminum Finishes

The Aluminum Association has developed a system of designations for finishes on aluminum. Three specific characteristics of finishes are each individually designated by a letter followed by a two or three digit number. The three finish components this system includes are mechanical finishing (M), chemical finishing (C) and coatings (A). The number which follows each of the above letters describes the type of treatment and appearance desired. Most common category designations are as follows:

Mechanical Finishes

  • M10 Unspecified (no mechanical finishing)
  • M22 Buffed to a specular finish
  • M32 Medium satin directional textured

Chemical Finishes

  • C22 Medium matte sodium hydroxide etch
  • C31 Highly specular chemical bright dip

Anodic Coatings

  • A211 0.1 mil thick clear coating
  • A212 0.2 mil thick clear coating
  • A31 0.4 mil thick clear coating
  • A33 0.4 mil thick clear coating
  • A34 0.4 mil thick with electrolytically deposited color
  • A41 0.7 mil thick clear coating
  • A43 0.7 mil thick clear coating
  • A44 0.7 mil thick with electrolytically deposited color

Using the System

When all components of the designation for a desired anodized finish are determined, they are put together in a string beginning with “AA-” to indicate that it is an Aluminum Association designation. For example, a matte champagne finish (AaCron finish #301M) would have the designation AA-M10C22A44.

AaCron Finish Aluminum Association Designation
101M AA-M10C22A41 (Also called 215-R1)
102M AA-M10C22A31 (Also called 204-R1)
103M AA-M10C22A212 (Also called 202-R1)
201M - 203M AA-M10C22A42
300M - 307M AA-M10C22A44
321M - 366M AA-M10C22A44A43

For any bright finish, substitute the C22 with C31, For example, a bright champagne finish (AaCron finish #301B) would have the designation AA-M10C31A44.

Please call us with any questions about this system.


In order to achieve the desired finish on any project, it is of utmost importance to utilize a specification which is specific to the aesthetic and performance standards desired.

For most applications, the specification should read as follows:

Finish: All exposed aluminum surfaces shall receive an anodized finish that is in conformance with Aluminum Association Designation AA-_________1. Color shall be _________2 as furnished by AaCron, Inc., Minneapolis, MN (763) 559-9141. The resulting anodized finish shall be continuous, fully sealed and free of powdery surfaces, blemishes and discoloration. The anodized coating shall meet all standards set forth by _________3.

Notes regarding blank spaces in the above specification

  1. Use the guide on the left column of this page to determine the Aluminum Association Designation that will be entered in this blank space.
  2. Refer to the front of this card to determine the AaCron Finish Code that will be entered in this blank space.
  3. Fill in the blank here with the appropriate industry standard. Some common examples are:
    • Architectural AAMA 611
    • Military (clear) MIL-A-8625F, Type II, Class 1
    • Military (colored) MIL-A-8625F, Type II, Class 2

It is also good practice to include information pertinent to aluminum alloy selection in the project specification. The aluminum alloy and its quality have a great impact on the resulting color and appearance of an anodized finish. This statement will vary depending upon material application and aesthetic requirements. AaCron Technical Services personnel are able to easily guide you through this process. Call us at 763-559-9141.

Special Considerations

All finish samples produced by AaCron are to serve as a reference standard to identify the color selected by the specifier. The appearance of an anodized finish is influenced by more than depth of color. Other factors include alloy, temper, gloss and surface structure. AaCron disclaims any responsibility or liability and makes no warranties express or implied of any kind in connection with the material and information contained herein.

Download color chart specification sheet