Designing for Visual Impact
Seven key points to consider for excellent video projection and environmental graphics.
Centuries ago, when light sources meant candles, wood fires and the sun, stained glass windows told Biblical stories and displayed symbols of the faith. During daylight hours, they also provided a constantly changing visual field, as beams of colored light moved slowly and steadily across the worship space.Today, colored light beams are more likely to come from video projectors and displays, but the intent is the same—to reinforce the message and meaning of a worship service, or to educate and instruct a congregation or study group. Environmental projection and large-scale displays can serve groups of thousands—provided both the building and the system have been properly designed. Here are some useful points to keep in mind during the programming and design phases of your next large-scale projection or video wall project. 1. Walls and ceilings are now the canvas, no longer the paintingFrescos, mosaics and other decorative surfaces are renowned as artistic expressions of religious intent. But today’s digital electronics allow a huge range of choices, so potential projection surfaces should be designed as blank canvases that will complement the technology, not obscure it. That may, for instance, affect the location of openings and any required structures that would break up a smooth surface. When LED walls are not powered on, they’re black (or at least, charcoal grey). Curtains may be an option here.2. Ambient light needs to be controlledNatural light is a wonderful thing, but of course it competes with reflected light from projectors and emitted light from video screens. The more ambient light, the farther from true black your system’s “black” is going to be: this is expressed as a contrast ratio. If you’re displaying abstract images or textures, contrast ratio is not so critical. But adequate contrast is essential for conveying information. Basic PowerPoint slides become visible at a contrast ratio of 5:1, but text and more complex images require higher contrast. Experts recommend a contrast ratio of at least 10:1, and 20:1 if you want to make sure that ambient light and contrast ratio will never be a concern for content producers. That means controlling both natural light and “spill” from your lighting system as tightly as possible. Of course, the brighter your screen and/or projector, the easier it is to achieve your contrast ratio target.3. Plan sightlines and viewing anglesWhile the general recommendation is for ±45 degrees (a total of 90 degrees) horizontal and ±30 degrees (60 degrees total) vertical, you need to consult with the owners during the programming phase about sightlines and viewing angles. Where will the audience be located? Does all of the audience need to see the entire image all the time? Will there be “main” elements that demand full visibility, and “supporting” elements that can be partially obscured at some locations? 4. Provide proper locations for projectorsThe people on stage or around the altar are a smaller group, but they are at least as important to the success of the program or service as the audience. If you are using projectors, they must be able to deliver images behind the people on stage without blinding them. Nothing is more distracting to a performer, presenter or worship leader than a sudden flash of overwhelmingly bright light.5. Adapt the system to the planned contentIronclad commitments are too much to expect during the programming phase, but it’s both legitimate and necessary to solicit ideas and general guidelines about how the space and the image-display technology will be used. Talk with your clients to distinguish high-focus informational content that needs both high resolution and high contrast from background or supportive images that can be less crisp and detailed. Will any or all surfaces be used for motion video? In general, motion video backgrounds need to be slow and subtle. There may be times when the presentation centers on film-style content, however. If so, that would certainly influence your design decisions.6. Consider staff capabilities and trainingHere’s another topic for the programming phase. Staff positions for visual content creators may be on the increase, but for most churches most of the time, this will still be a volunteer contribution. You need to identify who those staffers and volunteers are, what strengths, weaknesses and experience they bring to the task of image creation, and how much use they can make of available technology. Stretching those capabilities can provide long-term benefits to both the individuals and the congregation. But you still have to make sure that the tools in place are accessible by the people in place at the start—a system doesn’t have a “useful life” unless people can actually use it.7. Look for a meeting point between architecture and imageI can’t recall ever seeing a 16:9 structural wall, and I bet you haven’t either. How will you adapt common image formats to the physical space, and how much can you do to adapt the space to the needs of image display? Now that we have 4k projectors and processors delivering 4,000 pixels horizontal resolution, maximum image size has increased. That kind of leading-edge technology may fall outside the scope of your project budget: if so, you will need to plan carefully in order to deliver the proper image content.These are only broad-brush, general themes to consider when planning and designing a large-scale video project. Some of them may not be relevant—there’s little you can do to change the dimensions of a space when the project scope is confined to updating the AVL systems. Hopefully, these seven points will provide the proper starting points for your own investigations, so that devilish minor details won’t be overlooked until they become major problems.
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