This document specifies an instrumental method for determining the image clarity of anodic oxidation coatings on aluminium and its alloys by measuring reflection from the surface with the help of a sliding combed shutter.

The test is applied to a flat surface that can reflect an image onto the limited combed shutter and photometer. This method can also be used to measure the optical evenness of anodic oxidation coatings on aluminium and its alloys.