Visual Communication Systems-Part I

In Uncategorizedby tfwm

Visual Communication is becoming the norm for many of today’s churches.

My advice to anyone considering implementing a multimedia system in a church facility is, “Plan ahead!” The importance of planning and proper needs assessment cannot be overstated. This is especially true of new construction. Many churches wait until after the building is complete to consider designing a visual communication system only to find out that their church was designed in a way that makes it impossible.

There are many factors to consider when designing a building to accommodate a visual communication system. Among the many technical aspects of the design are such things as proper conduit for interfacing cables and supplied power for system components.

Consider also the cosmetics of the system. If these issues are not approached properly they can render a very expensive system virtually ineffective. The goal in designing a visual communication system is to provide a means of communicating information and a view of the service to everyone in the building whether they are in the front row or the last seat on the back row. This should be accomplished without deterring from the service. It is critical that the cosmetics of the system be the best that the individual components can provide. The most important issues in this regard are: the proper number of displays; the size of each display; proper placement of each display; the amount of ambient light between the viewers and the display; and the brightness of the displays.

The number of displays and the size of each display are issues that can be very closely related. The number of displays depends on the building layout. Some buildings may only require one screen to provide an image that can be seen clearly from any seat in the auditorium. Others will require two or more screens of the same size but facing different directions to provide a view to the entire auditorium. Still in other situations it is necessary to consider the display size and the distance to the viewers.

Properly positioning each display and the ambient lighting between the viewers and the display are also issues to consider. First determine what would be the ideal location(s) for each display. (If the building is being designed for construction the architect should be able to determine proper positioning for the displays) Trying different seats in the auditorium and checking the lines of sight is a great way to begin. The display should be able to be seen without having to move your eyes and/or head very far from the platform or altar. At the same time the displays should be high enough to be seen without having to dodge someone’s head in the line of view. However, it should not be so high that you have to spend the entire service looking up.

One of the factors that most strongly affects image quality is contrast. To put it simply, when dark is dark and bright is bright in the same image, you have contrast. Contrast is typically affected by a few things but most often by two primary factors: the projector/display characteristics and the amount of ambient light between the viewers and the display. It is important when determining display positioning to consider facility lighting. This can be challenging because the idea is to keep the display close enough to the important activity so as not to be a distraction or an inconvenience. Also, do not place it in the way of the lighting that is designed to highlight the important activity. Placing the display just outside the stage lighting perimeter is probably the best solution. This keeps the display close enough to the “action” so as not to draw people’s attention away while at the same time protects the display from the high-powered lighting that so badly affects contrast.

Another way to increase contrast is to utilize rear-projection as opposed to front-projection. Rear-projection is utilizing a translucent screen that is designed similarly to a television screen. The projection device is placed on the side of the screen opposite the viewing audience, and the image is projected onto that side and viewed from the opposite side. If a building is not constructed properly, rear-projection could be eliminated as an option. The reason for this is an entire room must be dedicated to the function of a projection room. A projection room must be deep enough to allow the projector to be placed far enough away from the screen to create the desired image size. Of course there are special lenses and mirrored systems that can make up for a lack of space but either of those significantly increase the cost of a system and reduce the amount of light hitting the screen.

A projection room should be equivalent to a dark room with all reflective surfaces covered in order to maximize the efficiency of the light output from the projector.

The amount of ambient light can be greatly reduced between the projector and the screen by “darkening” the projection room. This provides for much greater contrast and typically a brighter image.

In a front projection scenario any ambient light in the auditorium will add to the light hitting the screen which competes with the light from the projector. The more ambient light the less contrast or the more “washed out” the image looks.

Next issue, we’ll talk now about some of the components that make a visual communication system. Stay tuned!