Hairline

How to play

Putty first: one smooth stroke of the knife along the crack is the dream. Too slow or going over it twice leaves a bump, too fast leaves gaps, wandering off smears the wall. Then switch to Sand and rub it flush with the little block… and stop. Keep going and you’ll dig into the paint, and the only fix is filling it again. Done shows the wall under harsh side light, which shows everything. Under 0.5% is perfect.