-
Step 1
Choose the best projection type for the job. Transmissive projectors shine their illuminating light from the base of the machine. They produce brighter images and are good to use with computers with LCD projection capabilities. But they also are heavier machines. Reflective projectors shine their light down into a stage in the base, where it is reflected back up again through a lens and onto a screen. They work well with black outline transparencies.
-
Step 2
Determine the best lens for your purposes. Singlet, doublet and triplet lenses are available. The triplet lens produces the sharpest image.
-
Step 3
Buy the highest lumens available. Lumens are the brightness indicators of an overhead projector. Lower lumens will work with black outline transparencies, but higher lumens are necessary to produce sharp colored images.
-
Step 4
Purchase a projector with easy-to-find lamps. This is the part of the overhead projector that will need to be replaced with use. Some overhead projectors have lamp-saving features such as hi/lo switches. This enables the user to switch lumens. Other models have a lamp changer feature. The overhead projector has two lamps inside. If one burns out during a presentation, it's a simple matter of flipping a switch to keep the presentation moving right along. Both of these features are well worth the extra money.
-
Step 5
Check the warranty. Overhead projectors usually provide many years of service, but occasionally the wiring goes bad or a stage (the platform where the transparency is placed) gets scratched.
