Painting neat ceiling lines / room corners

stuart45

Or you can form a shadow gap between the wall and ceiling.

ouraggie

I paint ceiling first, then leave to dry for at least 24 hours. To do the top of the wall, I use a well-used radiator brush which has an angled head. I apply the paint in a long line about  2” below the ceiling, then gently work it up with my brush towards where the wall meets the ceiling. I keep a damp Jeycloth ( other brands are available) to wipe off any accidental forays onto the ceiling. With practice i have got rather good at it.