Distinctness of image is a measurement of how sharp and clear a reflection looks on a surface. A high value means reflections look crisp, like a mirror. It’s used to grade polished concrete because it reflects the refinement of the surface itself. Raw gloss readings can be inflated by a coating on top.
Why Distinctness of Image Matters on Polished Concrete
Shine and clarity aren’t the same thing. Picture two windows: one freshly cleaned, one with a thin film of grime. Both let light through, but only one gives you a clear view. Distinctness of image, or DOI, measures that clarity in a floor’s reflection.
That matters because a shiny sealer can hide a poorly polished floor. Many sealers can cover up scratches and boost gloss, so the floor looks great on day one and dulls once the film wears. That’s why polishing industry guidance calls for checking DOI with a clarity meter before any stain or gloss-boosting sealer goes on.
DOI ties directly to sheen levels. Higher levels are defined by how clearly the floor reflects what’s above it, from flat to nearly mirror-like.
Distinctness of Image FAQ
How is DOI measured?
DOI is read with a handheld clarity or gloss meter that checks how sharply the floor reflects an image. On polished concrete, readings should be taken on the bare concrete, before guards or sealers. For most homeowners, a simple look at how crisp the reflections are tells you a lot.
What is image clarity on a floor?
Image clarity is how sharp a reflection looks. On a highly polished floor, you can make out light fixtures and edges clearly. On a satin floor, reflections look soft and blurry. Learn more in our guide to polished concrete floors.