Picture Framing

An affect of non-uniform colour, or sheen level, that can appear when a wall is painted with a roller, but is brushed at the edges and corners. The brushed areas generally appear darker, resembling the "frame" of a picture. Also, sprayed areas may appear darker than neighboring areas that are brushed or rolled.

Possible Cause

• Usually a hiding (coverage) effect. Brushing will generally result in lower spread rate than rolling, producing a thicker film and more hiding.
• Adding colourant to a non-tintable paint, or using the wrong type, or level of colourant.

Solution

Make sure that spread rates with brushes and rollers is similar. Don't cut in the entire room before roller coating. Work in smaller sections of a room to maintain a wet edge. With tinted paints, be sure the correct colourant base combinations are used. Factory colours, as well as in-store tints, should be thoroughly shaken at the time of sale, and the product must be thoroughly stirred prior to use.

Images courtesy of the Paint Quality Institute from Dow Coating Materials