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 can only be applied to a flat surface which can reflect the image onto the limited combed shutter and photo-receiver. This method can also be used to measure the optical evenness of anodic oxidation coatings on aluminium and its alloys.