Video projection and video production are elements not commonly found in live performance spaces, yet there are the fastest growing form of communication in the contemporary technical worship center (CTWC) today. Currently, image projection is used two ways: 1) Graphics, videos, lyrics, sermon notes, and 2) Image magnification of worship team
The former is a modern-day version of the old overhead projector. The latter is a way for people in the rear seats of a large auditorium to experience the visual aspects of communication, ie,. facial expressions, which augment the spoken word, thereby better communicating or amplifying the message intent.
Regardless of how video projection is used, there are some baseline lighting considerations that must be taken into account. They are:
This is the overall amount of light, coming from anywhere and everywhere, bounding around in the room with no particular direction. Consider it the "glow factor" of the room. Unfortunately, it contains a lot of light travelling in a horizontal direction. Horizontally directed light is the enemy of image projection screens, since it tends to wash out the image.
Think of this as beams of focused light, whether from a general downlight, sunlight through a window, glow from a chandelier, or punch from a stage lighting fixture. It must be completely kept away from an image projection screen. When laying out general downlights, a common error is to forget the scalloping effect that may hit the screen from a light placed too close to the screen. When lighting a choir whose heads are dangerously close to the bottom of a projection screen, it is the spillover light above their heads.
Luminance of immediate screen surround
This is the reflected brightness of the surface that surrounds the projection screen. If the wall around the screen is white, or there are windows with a gorgeous view of the hills beyond set close to the screen, the luminance or brightness or the surrounding zone will determine how much light the eye will allow in. Considering the fact that any object whose luminance is five times the brightness of an adjacent object will set the eye’s iris to it, and hence determine what is seen, what is desired is a relatively dark field surrounding the screen. If the surface luminance of a typical image projection screen image is 22 lumens per sq. ft., and the perceived surface luminance of a picture window on a cloudy day is 2,200 lumens per sq. ft., the ratio is 100:1. The eye’s iris will narrow to accommodate the window, and any image on the screen will disappear into blackness.
For the sake of this article, we will focus on the general and stage lighting issues, and assume that the image projector, screen, and image sources are adequate to the task.
Lighting for Image Magnification
When image magnification (IMAG) is a part of the projection plan, a whole new crop of things are added into the lighting design pool. In essence, the lighting requirements for at least the stage (and possibly the auditorium) move into the realm of video. By this I mean that the lighting required to produce an acceptable image on the screen is really not much different than the lighting required for TV broadcast, or at least a good videotape. Suddenly, lighting levels want to increase, backlight becomes important, and color temperature needs to be considered. Allowable ratios of high and low lighting level extremes on the platform decrease substantially and hard-edge lighting wants to be diffused. While anyone remotely experienced with TV lighting design can rapidly describe a basic three—, four—, or five—point lighting plot in a studio, things suddenly change when the lighting instruments are 70' away from the stage, instead of 15 ' away. Let's look at some of the issues this presents:
Lighting is subject to the inverse square law, when it comes to illuminance intensity on a surface, at a given distance from the light source. Since the formula for illuminance is Foot-candles = Candlepower / distance2, this means that a 10,000—candlepower source will produce 100 foot-candles at 10' away. If we move the source out to twice the distance, or 20' away, will the foot-candles be cut in half? The answer is no. The foot-candle level at 20' away will be calculated like this: FC = 10,000 / 202 or 10,000 / 400 = 25 FC. So, if a 500W light fixture would work just fine in a studio, a 2kW unit may be required in a large auditorium when mounted at the front-of-house lighting beam.
No one in a television studio has a problem with the fact that all of the "guts" of the lighting and suspension system are on display for everyone to see. However, in a church auditorium, this may be a problem with some of the membership. Consequently, there are inherent placement limitations that must be factored in when designing the stage lighting in a CTWC that intends to do IMAG. Stage lighting positions will most likely be limited to one or two ceiling slots, with a limited amount of backlighting opportunity as well. Placement of all lighting positions must consider camera location(s) as well as seating layout.
There is a tendency to think "If an 8" 1kW fresnel works great as a key light in the studio, then a 12" 2kW fresnel will be what is needed way up there at the auditorium ceiling". This isn’t necessarily true. A fresnel is, by design, a short-throw lighting instrument. What is really needed is a different instrument (PAR or ellipsoidal spot) adapted to simulate the lighting effect of a closeup fresnel while far away from the stage. The fresnel is not efficient over a long distance, and the spill light it produces is very hard to control, when thrown a long distance.
The average congregation is not particularly comfortable with a lot of glaring light in their eyes during worship. Backlight and audience fill techniques used in a game show studio setting will be highly objectionable in a church setting. Extreme care must be taken to respect the worship experience of the live "audience" in church, while maintaining optimum lighting.
Lighting that looks good to the eye might not look good to the camera, and consequently not look good on the projection screen. Care must be taken to diminish lighting in the background during the sermon, since a uniformly lit stage will not bring emphasis to the person at the pulpit. A little bit of light on an empty choir riser will not look dark to the eye, but will probably disappear on camera.
Color temperature of lamps and other sources of light is of greater concern when video is an issue. The human eye and brain are excellent at color adaptation for many hundreds of degrees Kelvin, but a camera tends to show differences in color temperature as little as 200° K. When mixing sources, consider the color temperature of the lamp, particularly when dimming is used. For example, standard quartz lamps used in theatrical fixtures can range from a high of 3,300° K to a low of 2,900° K, when run at nominal voltage. Some incandescent PAR-56 lamps, such as the 300W version, can have color temperature ratings as low as 2,700° K. This represents a potential color shift of 600° K! Add to that the influence of daylight through windows (ranging from a low of 6,500° K to a whopping 10,000° K), and severe color problems can occur. This is particularly important in a multi-camera setting. There is something quite disturbing when your pastor, rabbi, or priest changes from yellow to blue when switching between cameras.
Physical and Architectural Issues
Placement of image projection screens can go a long way in improving image quality and allowing good lighting on the stage. Design of architectural elements and selection of finishes on the stage will also contribute to lighting and image quality. Here are some examples:
Screen Location All projection screens, whether designed for front projection or rear projection, have a fixed optimum viewing angle. The decision to use one central or two split screens is determined by the shape of the seating. In a wide fan seating situation, one central screen may not be the best decision, even if it is all the way at the rear of the stage and as big as a barn. Unless the side seats in the room are within the optimum viewing zone, the image on the screen will be dark and difficult to see. Furthermore, placing a large vertical surface designed to collect and reflect/refract light at the convergence zone of all stage lighting is asking for trouble. Consider the fact that a fan-shaped church usually has curved lighting ports that track the shape of the front of the stage, and all of the stage lighting is generally aimed convergent to the stage. Unless the stage floor is jet-black carpet, quite a bit of bounce light is going to be aimed at: guess what?–that’s right, the center rear wall of the stage. Most certainly this will wash out the screen image. By splitting the screens in a fan-shaped auditorium, and moving them out to the side, the amount of available viewing zone is doubled, and the screens are no longer right in the center of the convergence zone for bounce lighting.
Architectural Elements While a burnished metal handrail on the top of the modesty wall in front of the choir risers may look wonderful to the congregation, on camera it might just appear as a pipe running in one ear and out the other of your worship leader. Objects tend to lose their depth cues when on camera. There are other potential problems as well. Busy architectural designs or wood patterns or wallpaper may look good to the eye, but on camera it may compete with the foreground to the point of distraction. Or, it may set up a moiré pattern onscreen that swirls and scintillates every time the camera pans across the stage. Layout of all elements on the stage, and the effect of light on the object and surfaces must also consider how it will look on camera. Shadows of deep moldings not normally given attention by the brain will become large, dark bars or blotches on camera.
Material Finishes Shiny brass accents, polished black piano lids, gloss or semi-gloss paint, white paint of any kind, polished marble, lacquered wood and glass panels–all look really nice to a live audience. But they are the ultimate nightmare for a lighting designer and video director. These finishes and materials can create reflections and hot spots, which wreak havoc with a good video image. Dull finishes can look semi-gloss on camera. Shiny surfaces (we call them "specular") turn into lighting mirrors. The surface itself is not seen. All that is seen are bright blobs that are the reflections of the lighting fixtures. If shiny surfaces are not avoidable, then the lighting designer must consider the old rule "angle of reflection = angle of incidence" when planning the lighting for that part of the stage. This rules works great for flat surfaces all on one plane. But for round or curved or segmented surfaces, it may not be possible to find a lighting position that works, and avoids reflections into a camera.
Another issue to consider is carpet color. Some colors are very "video friendly.".Other colors are hostile to video or attempt to dominate the image. A good example is red. Red is a color that tends to dominate a video image. However, lavender and teal are very friendly to video, not dominant at all, and are complementary to skin tones. Certain oak varieties look brown on camera, while others turn greenish-yellow. And, if this isn’t enough to think about, add in the concern expressed earlier about the bounce factor of the carpet or floor finish. It is pretty much a certain guarantee that if the floor is polished hardwood, the back wall will always be overlit.
So, What to Do?
If building a new worship center, get the image projection specialist/consultant, lighting consultant, and architect together with the technical and ministerial users, as early as possible. Determine what your goals are for the room, and what you intend to do on the stage. Don’t think in limited terms, such as only worship services or only dramatic events. Anticipate all of the ways that video will be used. Then, develop a preliminary image projection design, house lighting design, and stage lighting design concept that supports these activities. This should all occur during the very beginning of the design, before anyone has "fallen in love" with the artist’s conceptual rendering of the building. More often than not, your crucial input early on will result in a building design that is different than it would have been if these things were not addressed until later, if ever at all.
For those who already have a building, and either are considering the addition of image projection or video production or both, do the same thing. Even though your architectural and structural options are limited by the existing building, good planning will identify and changes or adaptations required to maximize the value of your investment.
Lighting in a worship center environment with image projection and/or video production is inseparable from the image system. Don’t try to address either of them separately.
Paul Luntsford is an assembly space consultant, lighting-certified professional and president of PLA Designs, Inc in Aloha, OR. He can be reached at firstname.lastname@example.org.