Definition - What does Visual Comparator mean?
A visual comparator is a tool used to estimate the profile of a surface that has been treated by abrasive blasting methods. This handheld instrument consists of a flat sheet or plate with four segments, each representing different reference profile grades or textures. The tool is then placed on, or next to, the surface being inspected, enabling inspectors to visually compare the blasted surface against the reference profiles.
Visual comparators are also known as ISO surface comparators because they are governed by the standards set by ISO 8503-1 (Preparation of steel substrates before application of paints and related products).
Corrosionpedia explains Visual Comparator
Comparators are available in grit, shot or sand variations to allow for accurate comparisons of various blast media profiles. Comparisons can be made either visually or by touch. Most visual comparator tools have a hole in the middle to facilitate clear visual comparisons when placed on the blasted surface. Visual comparators are known primarily for their ease of use and portability.