Lapping

Appearance of a denser colour or higher gloss where wet and dry layers overlap during paint application.

Possible Cause

• Failure to maintain a "wet edge" when applying paint.

Solution

Maintain a wet edge when painting by applying paint toward the unpainted area and then back into the just-painted surface. This technique (brushing from "wet to dry", rather than vice-versa) will help produce a smooth, uniform appearance. It is also wise to minimise the area being painted, and plan for interruptions at a natural break, such as windows, doors or corners (especially important when applying stain to bare wood). Solvent-based paints generally have superior wet edge properties.

Images courtesy of the Paint Quality Institute from Dow Coating Materials