Choosing the Right Screen

In Uncategorizedby tfwm

At the Inspiration Conference a few years ago, an architect asked a projector manufacturer for his opinion about how to best design a church sanctuary for projection. The answer the designer received proved to be quite a shock. “Rectangular in shape, no windows and painted as dark as possible. It really should look like your local Cineplex.” Now, that may be a bit extreme but, at the same time, a great deal of planning must go into designing projection systems in worship spaces.

Much of the focus of choosing the right system is placed on the projector but choosing the right screen layout may be even more important because of the spatial design implications involved. With that, we move to the “screening room.”

One of the first decisions a church makes is whether its projection system will be front or rear projection. Despite the high image quality provided by rear projection, feasibility often becomes the point of contention. Creating a rear projection system is not a matter of simply mounting the projector behind the screen surface rather than in front of it; the ideal system is designed with the screen essentially acting as the front wall of a room used exclusively to house the projector. Although some lenses, along with the use of projection mirrors, can reduce the amount of space needed behind the screen in some cases, a general rule of thumb remains: the distance from the front of the lens to the screen could be as much as one and one-half to two times the width of the screen depending on the type of projector used. The depth of the projector should also be added to this final number.

For example, a church using a 12-foot screen and a projector that is four feet deep faces the potential need for 28 feet of depth in a room used only for rear projection. Obviously, it is difficult to retrofit a sanctuary for rear projection if this space is not planned for in advance. Not many churches have a room, (let alone two) of this size sitting empty, waiting to be used. In some instances, using a short-throw lens reduces the amount of depth required, but this raises other concerns depending on the quality of the lens. Since laying out a rear projection room can be difficult, it becomes imperative to bring in a system designer as early as possible to work with the architect and church staff.

Rigid screens produce excellent images and do a better job than fabric screens of masking the sound noisy projectors make. There are some obstacles, however, to using a rigid screen, the foremost of which is price. A rigid screen can cost easily four to five times that of a fabric screen, and this does not include hefty shipping costs. Also, rigid screens are limited to roughly 10 feet in height, so it is virtually impossible to get a taller one. Assuming these two hurdles can be cleared, the church still faces the challenge of actually getting the screen into its building. A rigid screen is just that: it cannot be folded or bent. Getting it inside a completely finished building requires large openings and a straight path to its final location. If the building is under construction, the screen should be brought in and stored in the room prior to the facility’s completion, meaning the church must make sure the screen is protected as construction goes on around it.

Flexible rear projection screens are constructed similarly to front projection models. Screen material is stretched across a frame and mounted. Fabric rear projection screens are significantly less expensive than rigid screens and also, because they are fabric, they can be folded and brought into the building late in construction. However, a fabric screen will not match the image quality produced by a rigid screen and it also will not block fan noise, which can be a major problem depending on the projector.

Yet if rear projection is simply not an option, the good news is that technology has improved so drastically, it is easier and less expensive than ever before to produce a high quality, bright, front projected image. Projectors with 5000 ANSI lumens of brightness and greater continue to become more affordable as technology advances.

When it comes to screen size, churches often adopt a true Texas approach–If 12′ x 16′ is good, then 15′ x 20′ has to be better. Try telling that to the architect who has to fit a 20-foot wide screen on an 18-foot wide wall. The truth is, bigger is not always better– or even possible.

The widely accepted formula for determining the right screen size works like this: measure the distance from the screen to the farthest viewer and divide this number by eight to determine screen height. For example, if the farthest attendee is 72 feet away, the formula dictates the screen would need to be nine feet (72/8 = 9) high.

It is important to remember that this formula does not factor the content of the projected material, however. In other words, the majority of projected material in a worship service takes the form of a PowerPoint or similar type of presentation, using few lines and large fonts. If this is the case, a smaller screen may be acceptable. However, if the church uses the sanctuary as a place to host computer training or study spreadsheets in a business meeting, a larger screen would be better.

Another important factor in determining screen size is actual physical space. Will the screen even fit? And even if it does, will it be obstructed by something–or someone such as a choir member? If a sanctuary’s ceiling is 25 feet high, the back choir riser is five feet off the floor, and one of the tenors plays for the Lakers, a 15-foot high screen may not work because Shaq’s head will be blocking the bottom portion. Suspended choir microphones and speaker clusters are other potential obstacles.

Believe it or not, screen size also affects brightness. The larger the screen, the less brightness the projector appears to generate. When the light output of the projector is distributed across a larger surface, fewer ANSI lumens per square foot are generated. The result: an image appears dimmer on the larger screen than the same content projected on a smaller screen where light output is more concentrated. When this principal is applied to a projector, the same image will appear brighter on a 9′ x 12′ screen than on a 12′ x 15′ screen. When calculated, it is possible to see as much as 10 more ANSI lumens per square foot on a smaller screen compared to the next size up.

A discussion about screen size is not complete without addressing aspect ratio (screen height versus screen width). Most computer and video images presently have 4:3 aspect ratio displays; four represents screen width and three, screen height. For a 4:3 image to fill a screen, the screen must have the same aspect ratio. This is why screens come in sizes like 9′ x 12′, 12′ x 16′ and so on. This is also why a computer image will not fill a square screen–an 8′ x 8′, for example. In this case, there would always be unused space above projected images because computer and video images are not square.

The next decision is when to convert to a wide screen or 16:9 aspect ratio. As increasingly more video programming is produced in the wide screen format, the need for nontraditional screens will grow. So, when does the conversion become necessary? While wide screen video is becoming more available, the predominant content continues to be 4:3, so the conversion of one or the other is required to accomplish both. The answer, as noncommittal as it may seem, is to examine where the church is in its use of visual communication. If a 4:3 system is currently being used, there is no pressure to jump the gun and convert. The truth is, this church may need a new sanctuary before conversion becomes necessary. On the other hand, if it is in the process of implementing a new system, 16:9 might be a good idea. However, few projectors are producing a true 16:9 image at this point, so living in both worlds is difficult but not impossible.

For these questions, there are no standard answers. Decisions depend on sanctuary design and church budget.

Let’s look at the movie theater concept. Most cinemas are rectangular and every seat faces the screen. Placing one screen in the center always works well because no viewer is seated off-axis. For the most part, everyone watching has the same view. Churches of similar design are no different. Many sanctuaries, especially those that have been around for decades, are designed this way.

Many contemporary designs, however, place seating in a fan shape with some people seated in the wings. Here, two screens are typically more efficient. An important factor to consider when using two screens is the need to maintain the audience’s focus on the center of the stage where the pastor is located. The last thing he or she wants to do is to look out at a crowd and find them looking away. To prevent this, screens should be placed at an angle with the stage left screen facing the stage right audience and vice versa, not flat against walls.

The drawback: this design roughly doubles the price since a second projector and screen will be needed. Also, more equipment will be needed to distribute the signal to both screens. One more factor in using dual screens is that not all projectors can be perfectly matched. This leaves open the possibility that choir robes could appear blue on one screen and green on the other. Once again, a system designer can help avoid this problem.

While the above solutions take care of those seated in the sanctuary, what about the people onstage? Until recently, the standard solution was to provide video monitors, but this presents its own set of problems. Should monitors be flown from the ceiling or placed on the floor? The latter idea may work, but if the service is televised, the choir can look awfully drowsy constantly dropping their eyes. Also, a television monitor may not be especially pleasing to look at if it is hanging from a ceiling. Also, it may not be large enough to be effective, especially when text is displayed.

In response, churches are adding a screen at the rear of the sanctuary. The images projected on this screen may or may not be identical to those on the main ones at the front of the sanctuary, but it depends on the sophistication of the system. The downside to adding this third screen is, again, cost. Aside from buying one more screen, another projector–plus the peripheral equipment needed to distribute the signal to this screen–will be necessary. However, this third projector may not need to be as bright as the main projection system since churches often use less light at the rear of a sanctuary.

In most situations, a matte white screen surface remains the ideal choice. These provide the greatest viewing angles, allowing even people seated off-axis to view text and images.

There are a few cases when high gain screens are the best choice. If seating extends straight out from the screen with no one seated significantly off-axis, a high gain screen provides greater light reflectivity, which results in a perceived brighter image. However, the drawback to these screens–other than poor off-axis viewing–is a tendency to “hot spot” (the center of the screen appears brighter than its edges and corners).

These guidelines are not intended to be all-encompassing, but they are a good jumping off point. Find a system designer that understands not only the technical intricacies of the system but the ministry’s objective as well.

While the dark rectangular room may provide the best images, who really wants to worship in a movie theater? Besides, church is where light overcomes darkness, not the other way around.