A non-uniform, colour or sheen variation or poor opacity appearance may occur when a wall is painted with a roller and the edges are cut in with a brush.
Cut in and roller application must happen while paint film is still wet to form a homogeneous film. If cut in happens after roller application, this might form a darker patch due to an additional dry film thickness.
Cut in after roller application has dried.
Roller application into cut in before paint dries to create a uniform film.
Remedy
Apply a single coat CoverCoat, MaxiCoat or UniversalUndercoat over previously painted stable surface to block out uneven colour/colour variation.
