While projecting video or slide software images onto a white painted wall isn't a bad idea, there's a reason that Hollywood movie studios have always focused on the silver screen. Commercial projection screens are made from a silver or gray reflective material because they display color and contrast more dynamically than an ordinary white bed sheet. You can best approximate this effect by painting your home theater wall with a specially formulated projection screen paint.
Smooth as Silk
Before painting your screen surface, smooth over any chips or chunks or other irregularities. Remove nails or picture hooks, and gently scrape away any rough spots using a putty knife or sanding block. Fill any holes or cracks by applying a drywall compound or mud with a putty knife and let dry for up to 2 to 3 hours, or as directed by the manufacturer. Apply additional mud if needed for cracks that appear during drying. When fully dry, sand the area smooth. Wipe the wall with a tack cloth to remove any remaining sanding dust before applying your paint.
The Best Paints
Economical paints include pure white interior latex with names such as super white, ultra-white or pure white in a eggshell or satin sheen applied with an airless sprayer or a short-nap roller. But for the best paints, choose ones with product names such as "projection screen paint" "video screen paint" or "cinema screen paint" found at some of the major home center stores or through online suppliers. For increased visual clarity, apply a 2 to 3 inch border with a flat black paint around your screen's perimeter. Use painter's tape when applying the border to create the cleanest possible edge.