Projection screens - better than a plain white wall?
Projection screens cost money. So every day we get emails asking, "Can't I just use a plain white wall and save the screen expense?" The answer is simple: Absolutely you can! And you can save money by putting regular gas in your Porsche also. It will run, you just won't get the best performance out of it.
Projection screens have optical coatings that enhance their reflective properties. White walls don't. You can certainly use a wall if you want to, and you will get a watchable image. However, compared to the image you'd get with a screen, highlights will not be as brilliant, contrast and color saturation will be reduced, and (depending largely on the texture of the wall) sharpness will be reduced as well. You will end up with an image that is not as good as your projector is capable of delivering.
Furthermore, one very important but often ignored benefit of a screen is not actually the screen, but the frame. A solid black frame around a video image substantially boosts the visual quality of the image itself. So unless you paint a black rectangle on your wall, by foregoing the screen you will lose this vital component in the overall visual experience.
Now, for those starting out with their first entry level home theater projector, a white wall is much better than nothing. Just make sure it is white. Don't paint it gray thinking you will replicate a Stewart Firehawk. You won't. The essential magic of the Firehawk is in its optical coating, not just the simple fact that it is gray. So if you paint your wall gray you will get an even duller image than you would by leaving it white--paint your wall black and you will get no image at all.
Think about this for a moment...you will probably upgrade projectors every few years, as you will DVD players, audio components, etc. But high quality projection screens will last a lifetime. So we'd suggest you think of it in terms of a lifetime investment. That means study your options, plan for it in your budget, then make the investment once and be done with it. If you are serious about good image quality, you will always be glad you did. (EP)