Here are three of the most commonly asked questions by worship leaders when it comes to selecting a screen for sanctuary video projection.

How do you choose the screen surface?
There are four elements to consider for front projection:

1. Reflective characteristic of the screen
2. Required viewing angle - The Cone of View
3. Ease of maintenance
4. Flame retardant

Viewing angle determines where you can be in the room and still see a good-looking image on the screen. It is expressed as “degrees off center axis.” Here is an example: 50-degree angle of view means that if you stand with your back against the screen and look straight ahead, the image will look good up to 50 degrees to your right and 50 degrees to your left.

1. A flat matte white screen gives the widest angle of view, typically 50 degrees.
2. Glass beaded screens reflect a brighter image but in a narrower cone of view, typically 30 degrees. They are difficult to clean.
3. Ridged (lenticular) screens are also bright with a narrower cone of view, typically 40 degrees, but are easier to clean.
4. The most common flat screen is matte white. It provides the widest angle of view and a good uniform surface, and it is the most versatile and easy to clean.

Keep in mind that the cone of view is not just width but also height. This becomes important if your screen is mounted relatively high. With today’s brighter projectors, the cone of view is more critical than the reflective characteristic.

What is rear projection and when is it the best method?
Rear projection is when a video projector is located behind a translucent screen and the light of the projector shines through the screen. A thin film in the screen acts as the diffuser. The image will appear backwards to the audience, so the image will need to be reversed. Most all of today’s projectors are capable of reversing their image for the purpose of rear projection.

Advantages include:

1. The contrast is better than with front projection. (The screen material is gray instead of white helping the dark images to look blacker.)
2. Because the screen surface is not reflective, it is not as affected by ambient room light, making it more suitable for sanctuaries with windows and hard-to-control light levels.
3. The light from the projector to the eye is direct rather than reflected, offering a better image.

Disadvantages include:

1. The projector requires considerable space behind the screen, typically more than 16 feet. The distance is determined by the size of the screen and the lens used. The use of mirrors and custom wide-angle lenses can reduce the distance but raise the cost considerably. The space behind the screen needs to have relatively good climate control and be completely dark.
2. The cost of the installation is typically more than with front projection.

If you have the space behind the screen and can afford the difference in cost, rear projection is almost always the better way to go because of the superior image that it produces.

Which rear projection screen surface is the best?
There are three basic choices of screen surfaces for rear projection:

1. Glass
2. Plexiglas
3. Flexible stretch material

Glass and Plexiglas are similar in weight, price, and quality. The extremely thin diffuser in the screen produces extremely sharp images. However, these screens are expensive, difficult to ship, difficult to install, and nearly impossible to repair.

The stretch material type is affordable, east to ship and install, and can be removed for service and repair. The image may not be as sharp as the glass screens, but the image is certainly sufficient for use in sanctuaries.

Snap grommets or Velcro attach the screen to an aluminum frame that is fitted into the hole in the wall. After the hole is made to the specs of the screen, the frame is attached to the wall and then the material is stretched and attached to the frame. To service the screen, simply pull the screen off the frame.

Rear projection is an excellent choice, but it brings several design challenges. Most users choose the flexible screen surface.

Please note that front projection can also be done with a flexible screen surface mounted on an aluminum frame that is simply attached to a wall or flown from cables.

This information is courtesy of Film Otter Productions, whose background images have been used by churches all across North America, www.filmotter.com.