Ambient light, room size, and projector specifications, determine the type of projector screen that will work best for your needs. You can choose from a front projection screen - wall mounted or portable, manual or motorized, or fixed wall screens, or even (uncommon except in very expensive setups, a fancy rear projection screen. If you are in a classroom, mounting the projector screen over the front whiteboard, typically works best. Most home theater projectors are ceiling or wall mounted, some are "table top". How far back you mount, how wide a "cone" your audience sits in around the screen are factors in screen selection. Business projector systems are most used for presentations, etc., that require more portability, including, sometimes a fast setup projection screen.
These are common setups because they are the most inexpensive alternative. Manual projector screens pull down like a window shade when needed and flip back up between uses. Manufacturers have created tensioned models to enhance picture quality and solve the issue of bends and folds in non-tensioned screens. There is a manual screen case, Controlled Screen Return, that stops the projector screen from rolling back too quickly.
Article on Projector Screen Terminology:
Advice and factors in deciding which projector screen is right for you.
Let's define the two most important terms that screen fabric directly effects.
Screen gain is the measure of light reflectivity. A gain of 1.0 is the industry standard; 1.2 is 20% higher reflectivity.
Projector screen viewing angle is about where you can sit in a room, relative to the projector screen and still have a fairly evenly lit, bright image you can view. Higher gain screens are brighter, but are best seen sitting straight back from the center of the screen, or not to far from that point. If you have a 2.5 gain screen, you do not want to be sitting 35 degrees off of center, it will be dim. With a 1.3 gain screen, sitting in that same off angle area will be just fine.
High contrast gray screens mean that whites are less bright, and "blacks" (black levels) are closer to actual black. Grey screens depend on sufficient projector luminosity, but reflect less room light than white screens which make them more effective in rooms with ambient light coming from other sources than the projector - especially ambient light coming from the sides, perhaps a window or wall sconces that you want left on while viewing. High contrast gray screens started off, primarily to lower the black levels, but today's better projectors (starting below $2000) have far more "impressive" blacks than the projectors of more than 5-6 years ago. Thus, today, the high contrast gray projector screen is probably selected more for the handling of ambient light than for blacker blacks.
As gain, or light reflectivity, increases, viewing angle decreases, so understanding the room your projector will be setup in is very important to determine the material your projector screen will be made out of.
For more details -an in-depth understanding on the topics of touched on here, I've included some additional articles below:
Article on Projector Screen Quality
An intro to choosing a quality projector screen. Article by Stewart Filmscreen.
There are four basic formats:
Do not compromise on a screen after putting your investment in to the projector; this would be selling yourself short like buying an HDTV, without connecting the cable through HDMI.
When ordering a projector screen, most screens are "special order". Get it right the first time to avoid large restocking fees. You'll want to remember to figure in the width of the frames, and other key factors, or you'll pay the price...