This part of ISO 8503 specifies the requirements for ISO surface profile comparators, which are intended for visual and tactile comparison of steel substrates which have been blast-cleaned with either shot abrasives or grit abrasives. This part of ISO 8503 also includes definitions of the terms used in the ISO 8503 series and requirements for the care of ISO surface profile comparators. NOTE 1 ISO surface profile comparators are used for assessing, on site, the roughness of surfaces before the application of paints and related products or other protective treatments. NOTE 2 Where appropriate, these ISO comparators can be used for assessing the roughness profile of other abrasive blast-cleaned substrates and, in addition, their use is not restricted solely to surfaces that are to be painted.