The method is based on light coming through a first slit (light source), being converted to parallel light through a first lens (collimator), reflected at the surface of the test piece, focussed at a combed sliding shutter through a second lens (condensing lens). The signal measured by a photo-receiver behind the shutter is a measure of image clarity. Optical evenness of the test piece is shown by the ratio of the longitudinal and transverse values when the shutter is appropriately slid.
ISO 10216:1992 history
2017ISO 10216:2017 Anodizing of aluminium and its alloys - Instrumental determination of image clarity of anodic oxidation coatings - Instrumental method
2011ISO 10216:2010/Cor 1:2011 Anodizing of aluminium and its alloys — Instrumental determination of image clarity of anodic oxidation coatings — Instrumental method — Technical Corrigendum 1
2010ISO 10216:2010 Anodizing of aluminium and its alloys - Instrumental determination of image clarity of anodic oxidation coatings - Instrumental method
1992ISO 10216:1992 Anodized aluminium and aluminium alloys; instrumental determination of image clarity of anodic oxidation coatings; instrumental method