There is a wide variety of screens each one with a choice of projection surfaces. Selecting the right combination to meet your needs is important for optimum results.

The following is a guideline for selecting a screen that suits your application. Although these recommendations will work in most situations, each must be looked at not as a strict rule, but rather as a guideline for determine your actual needs based on your own situation.

Pick the type screen that best suits your particular needs. For example, choose form front projection or rear projection screens in either potable, wall or ceiling mounted models in either manual or electric versions. Generally, if your projection application is permanent, then wall and ceiling screens are your best choice. If, however, you find your needs require moving the screen to different locations then a portable screen is a better alternative.

Determine the optimum screen size based on room dimensions, planned audience seating size and arrangement. The rule of thumb is to fit the screen to the audience-not to the projector.

I recommend the following formula for determining screen size:

Screen height should be approximately equal to 1/6 the distance from the screen to the last row of seats, allowing text to be read and detail to be seen in the projected image.
Ideally, the first row of seats should be approximately 2 screen heights away.
The bottom of the screen should be a minimum of 4 feet above the audience floor, allowing those seated toward the rear of the audience to see the screen. This may require additional screen "drop" for ceiling hung screens.
Select the appropriate format for your projection application. Common formats are as follows

Common Applications and Aspect Ration Width/Height NTSC Video 1.33
PAL Video 1.33
Letter Box Video 1.85
HDTV Video 1.78
35MM Filmstrip 1.32
2x2 Standard 35MM Double-Frame Slides 1.50

Choose the screen surface that best suits your projection and viewing requirements. If the screen will be used for multiple projection methods, choose the screen surface that meets the requirements of the lesser performing projection method. For example, if using a slide projector and a video projector, choose the screen surface for the video projector since its light output is generally less than a slide projector.