Choose and purchase latex paint in the color of your choice. Stir the paint with a paint stick so the color and texture of the paint is consistent.
Place drop cloths on the floors and furniture in the room. This will protect your home and furnishings from damage as you paint. Also put on work clothes and safety glasses for painting. The glasses will keep the paint from getting in your eyes as you paint the ceiling.
Pour the latex paint into a paint tray. Place a looped paint roller cover on a paint roller. The looped cover is important because it will help reach into the knockdown texture on the ceiling.
Roll the paint roller in the tray until the looped cover is coated with paint.
Begin applying the paint on the ceiling in a W pattern. Cover the main area of the ceiling with the paint. The paint will not reach into all areas of the knockdown texturing. You may need to use a paintbrush to reach these areas.