BS EN 462-2:1994(2008) Non - destructive testing — Image quality of radiographs — Part 2 : Image quality indicators (step / hole type) — Determination of image quality value
2013BS EN ISO 19232-2:2013 Non-destructive testing. Image quality of radiographs. Determination of the image quality value using step/hole-type image quality indicators
1994BS EN 462-2:1994 Non-destructive testing - Image quality of radiographs - Image quality indicators (step/hole type) - Determination of image quality value