Sheen, explained

Sheen is graded by gloss level, from flat (G1) up to high gloss (G7), measured at 60° and 85° (85° readings apply only to the low sheens, G1–G4). Brand names don't always match these ranges, so the product data sheet is the final word.

Flat hides flaws best and suits ceilings and low-traffic walls. Satin and semi-gloss hold up in kitchens, baths, trim, doors and cabinets.

The rule of thumb: more sheen means more durability and washability, but less forgiveness of flaws.