The visibility of your projected image depends on three important features: the brightness of the projector, the projection surface, and the type of lamp in your machine.

Brightness
Your presentation will crash and burn if your projector cannot produce enough light to throw images across a room and onto a screen. Accordingly, the brightness (measured in ANSI lumens) of your LCD projector or DLP projector is a key consideration.

While projectors with fewer than 1000 lumens may be sufficient for projecting black and white images in dark rooms, they may not have enough firepower to keep multicolored PowerPoint presentations from appearing washed out. When deciding how much brightness your projector should have, keep in mind how dark the rooms will typically be for your presentations and how far your projector will be from the screen. The basic rule of thumb is that big rooms with more light require brighter projectors.

Brightness ranges from 1,000 lumens for ultralights up to as much as 10,000 for fixed machines. For on-the-road presentations, 1,000 to 2,000 lumens should be fine, while larger conference rooms will need 2,000 to 4,000 lumens. Fixed installation machines in large auditoriums can require 4,000 to 5,000 lumens and up – but be prepared, these machines carry much higher price tags.

Projection surfaces
Screens are much better reflectors than plain walls, so they make projected images much more visible: you may need more brightness if you often present in locations without screens. If you purchase your own screen, you'll have to choose between white and grey backgrounds.

Perceived color in a projected image is a factor of both the projection surface and projector quality. White surfaces are best suited for natural color tones; as such, white projection surfaces are more common in most business and school presentation environments.

However, darkest black in a projected image is dependent on how dark the screen is. Because of this, some presenters and presentation space planners prefer gray screens, which create higher perceived contrast. The trade-off is that darker backgrounds can throw off color tones. Color problems can sometimes be adjusted through the projector settings, but may not be as accurate as they would on a white background.

Lamp Type
Also related to image brightness is lamp type. The most common types are UHP (Ultra High Performance) and UHE (Ultra High Efficiency) lamps; some models still use metal halide, as well. Lamp life will be rated for any projector you buy – typical lifespans are between 1,000 and 4,000 hours. Typically, lamps don't burn out suddenly, but gradually grow dimmer, giving you plenty of warning that it’s time for a replacement.

Lamps can be one of the hidden costs of a projector, as they are likely to burn out or break sometime over the life of your machine and replacement bulbs cost $250 - $600. Knowing the replacement cost of the lamp can help you determine your future spending on a given projector.

If you are comparing two projectors of the same brightness, ask about the wattage of their respective lamps. If there is a difference, go with the projector that has a lower-powered bulb. The low-watt lamp will last longer, stay cooler, and be more efficient than a bulb with a higher wattage.

Also look for projectors that have an “economy mode.” This setting reduces the power consumption of the projector, cutting brightness by about 20% in exchange for less noise, reduced electricity usage, and longer lamp lifespans. Some models have a bulb lifespan of 3,000 hours in economy mode, as opposed to 2,000 hours in standard mode.