How to Paint Over Brightly Colored Walls

Sand the walls with a fine grit sandpaper on a pole sander to roughen the surface and diminish high spots.

Wash the walls to remove grease, oils and loose dirt. Rinse down the walls with plain water to remove remnants of the cleanser. Allow the walls to dry thoroughly.

Select high-quality brushes and rollers to paint and prime the wall. Choose a brush with natural hairs, typically hog bristles, for oil-based paints and a synthetic fiber brush, typically nylon or polyester, for water-based paints. Choose wool blend roller covers with 1/2-inch naps to hold a sufficient amount of paint that you can spread evenly on the walls.

Roll or brush paint primer on the walls with the goal of building a barrier that prevents the underlying color from coming through and creating a uniform surface for the paint layer. Dry according to the manufacturer's specifications for the temperature and humidity levels in your room. If any of the bright color can be seen through the primer, apply a second coat and allow to dry thoroughly.

Paint the main part of the walls with your choice of a paint brush or roller using a high-quality paint that has a high volume of pigments and resins as compared to solvents, most often found in higher priced paints. Apply the paint with a brush to the inner corners, ceiling edges and along the baseboards.