The biggest advantage of buying a projector screen is that it gives you more control than you’d get with a bare wall. A perfectly smooth wall is great, but any minor imperfections could harm your projected image.
The color of your wall will be the biggest factor. If you own your home, this is less of an issue, but renters may be stuck with a wall color that would make a projected image look too dark or too bright.
Even if you have a perfectly smooth, white wall, you still might want to get a projector screen. Most screens have a black border around them, which helps frame your movies and TV shows. A screen also gives you a bit more control over how much light gets reflected: a screen with a matte coating will have a much easier time of keeping ambient light from ruining your image.
