How to Lighten a Paint Shade for My Ceiling

Get a quart or gallon container of the same exact same base white color as used to mix your colored paint. Purchase the same brand, type and the same finish as the paint you're using.

Make sure your colored paint is closed well. Turn the can upside-down for 15 minutes. This helpw the pigment that has settled on the bottom, mix back into the paint base. Turn the can right side-up and open it.

Stir for several minutes to ensure the pigment and other elements in the paint are evenly distributed. Pour the paint into a large bucket.

Open the white base and stir it for a couple of minutes to thoroughly blend all the paint components.

Pour the white paint base into the color base in small increments, about 1/4 cup at a time. As soon as some white base is added, stir it into the color paint.

Stop adding base when you are approaching a color you like. It's better to err on the side of caution; you can always add more white to lighten it further, but you won't be able to darken it again if you go too far.

Brush a thin coat of the new color onto a piece of scrap wood or cardboard. Turn on a hair dryer and aim it at the painted scrap for a few minutes to dry it. Since colors look darker when they're dry, you'll have a better indication of what the finished color will be if you dry your test scrap.

Add more small amounts of white base paint if necessary and stir if you want to lighten it further. Make another test patch on scraps. Continue tweaking the color until you are satisfied.