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Front Projection Rear Projection

By far the most widely used projectors today utilize LCD technology. This popularity is due to their low cost, lightweight, and ease of use compared to other projection technologies, such as Cathode Ray Tube (CRT) systems. LCD projectors separate the red, green, and blue information to three LCD panels. The appropriate colored light is passed through each panel, and then combined to exit through the lens as one image.

There are a couple of key characteristics that determine a projector's image quality:

Resolution determines how sharp an image appears on the screen: The higher the resolution, the sharper the image. Of course, the projector must be capable of displaying an image at the same resolution as the source. If your computer monitor is set to 1024 X 768, the projector must be rated at that resolution. If it's not, you'll need to set your computer's resolution to match that of the projector. (In Windows, select Start-Control Panels-Display-Resolution.) Keep in mind that higher resolutions are required to display fine details, such as spreadsheets, but lower resolutions are fine for things like large text, bar graphs, and the like.

Brightness is usually listed in ANSI Lumens, which is a standard measure of light output. It varies from about 100 to over 12,000 ANSI lumens. Not surprisingly, brighter is generally better. The advantage of brighter images is that you can have a higher level of ambient light while still maintaining an acceptable image. Brightness, along with resolution, are the two most important specifications to consider when purchasing a projector.






Front-projection systems are more widely used in business than any other display option. They are cost-effective, versatile, and reliable. With projectors getting better and brighter every year as prices go down, this will ensure front-projection's dominance for the foreseeable future.

One of the drawbacks that limited the usefulness of front-projection in years past was the need to turn off room lights in order to see the screen. The only way around this was to use rear-projection, which isn't so affected by ambient light. But that required a more complex and expensive installation.

This problem has basically been eliminated due to increased brightness of today's projectors. With more brightness, the projector is able to "punch-through" higher levels of ambient lighting, resulting in clearer images onscreen. One of the other advantages is that you can vary your image size dramatically, depending upon how close or far the projector is to the screen.

Projectors range from less than 2 pounds for the mobile presenter on up to huge light cannons designed for live events such as the Academy Awards. Somewhere in between those extremes is your typical ceiling-mounted boardroom system.

The best way to compare projectors isn't reading catalogs, it's seeing the projectors making images. That's something you can see at Spectrum's showroom. Just call for an appointment!






Rear projection systems place the projector in a light-tight space behind a screen designed for this type of display. This has several advantages over front-projection systems. First, ambient light has relatively little effect on rear-screen systems, so you can leave the room lights on. Second, the projector isn't located in the middle of the room or on the ceiling, so fan noise is greatly reduced. You also don't need to keep the center of the room clear to maintain a light path. You can even walk in front of the screen without casting shadows on the image and getting a face full of light. Some screens can also be written on with dry erase markers. The one drawback with rear-projection systems is that they are more expensive, but many consider the advantages to more than justify the cost.