Using a painted surface for a projector screen can have mixed results. Some paints will result in accurate colour reproduction, others specialise in vibrant tones with deep blacks, and some will provide you with the best screen conditions for viewing in ambient light situations. Finding a paint that gives the best results under any condition can be an expensive undertaking that requires a search for speciality products and extensive pre-application surface work. You can avoid most of that by creating your own paint for a projector screen that results in high-end picture quality for a small cost.
Black Widow Mixture
Use a mixture of paints in order to achieve the best results for your projector screen. The best mix is one named Black Widow, a combined grey paint that's made using aluminium paint with a common base. The aluminium paint must be water based such as Createx Auto Air Fine Aluminum grey paint. Use a flat enamel finish as your base. A good choice for this is PPG's The Voice of Color Bermuda Beige paint.
Mixing your own paint for a projector screen is the best way to get a colour that results in a neutral grey. A neutral grey colour tends to eliminate colour contamination from reflected light, giving the viewer the most exact representation of the image possible. It's also a good choice for your viewing room as it's more forgiving of changes in room lighting than a pure white screen, so you're able to project onto the surface in multiple lighting situations.
Create the Black Widow mixture with a 4-to-1 ratio consisting of 1qt. of the Bermuda Beige paint to 227gr. of the Fine Aluminum, giving you 1134gr. of paint to work with. This should be enough to cover a surface containing a 100-inch screen.
Apply the Black Widow mixture as you would any other wall paint. Use a good quality low-nap roller for the paint application. For best results, prime the surface with any high quality white primer. Avoid foam rollers for paint application as they have the tendency to cause bubbles, which, when popped, leave bright spots on the screen surface. They can cause picture distortions. Roll over any bubbles which may appear in order to avoid this problem.
Compare the applied Black Widow mixture to an untreated wall and you'll find that the mixture produces some very visible results. Your new screen paint will present deeper blacks with a wider band of shades visible. Colours will be bolder, also presenting an increase in shades with more natural tones. Your image should on the whole be brighter, sharper and more vibrant. The picture should also be more visible in ambient light settings, working nearly as well as in no-light settings. All of this costs less than £65.