Remove furniture from the room and place a drop cloth over the floor. Place drop cloths over the furniture if moving it isn’t possible. Put newspaper on the walls and tape it in place.
Pour the paint into the bucket. Mix the paint together if you have more than one can of paint. This produces a uniform color. Thin the paint with 1 to 2 cups of water.
Fill the paint sprayer with the thinned paint. Adjust the pressure so the paint sprays a fine, even mist.
Point the paint sprayer at the ceiling about 12 inches from the surface and move your arm back and forth as you spray. Don’t stop moving your arm while you’re spraying. Keep your wrist straight so you can get an even layer of paint over the whole exposed ceiling. Overlap each area with the next to create an even finish. Use a ladder to reach the high points in your ceiling, if needed.
Cover the entire ceiling with an even layer of paint and allow it to dry. Apply a second layer of paint for an even finish.