CNET puts projectors through a rigorous and unbiased testing process that’s the culmination of more than two decades of projector reviews. We use specialized test equipment, including a Photo Research spectroradiometer, a Minolta LS-100 luminance meter and an AEMC CA813 illuminance meter. The data is collected and collated by Portrait Displays CalMan Ultimate software, which helps us evaluate every PJ we review. Every lamp-based projector is “burned in” for 50 hours before measuring, and all projectors are initially set up using their most accurate color temp and color modes. Test patterns, sent from CalMan, are then used to adjust the various picture settings so the projector looks its best before measurement and evaluation. Contrast ratios are measured in each lamp and iris mode (when available). Once the projectors are fully set up and objectively measured, we watch a variety of content, including TV, movies, and games, both with the projector by itself, and compared side-by-side with two direct competitors.
Broadly speaking, we’re looking for the three picture quality aspects: contrast ratio, overall light output and color reproduction. Contrast ratio is the most important part of any projector’s performance. It’s the difference between the darkest part of the image and the brightest. While certain TV technologies, like OLED, can create a black that’s the actual absence of light, no projector technology can do this. Because of this, contrast ratios with projectors are far lower. It’s the difference between a washed out and “flat” image and one that’s more lifelike and “pops.” The better projectors will have a measured contrast ratio in the thousands. Most are between 500-1000:1.
Light output is the second most important factor, because it’s not only how bright the image appears on your wall, but also how big an image you can produce. Most modern projectors are significantly brighter than projectors from even 10 years ago. We measure brightness in candelas per square meter (cd/m2) and then convert to estimated lumens for ease of comparison. It’s important to note that we use the most accurate color temperature mode for our brightness comparisons, but we’ll note when a less-accurate mode is significantly brighter. Most of the projectors we test are between 1,000-2,000 lumens, with battery-powered models far less, and some specialized projectors even higher.
Color accuracy is the last major factor. No projector can truly take advantage of HDR or wide color gamut, but some can do more than others. Generally, we’re satisfied with accurate colors, but adding HDR effects is a bonus. Most home theater projectors we test are fairly accurate. Budget models, those that prioritize brightness over everything, and PJs from newcomers to the projector space, often have wildly inaccurate colors that result in a very unnatural image.
Other factors, like video processing and HDR processing, are evaluated in the viewing tests. These are rarely a major factor in projector performance, but some models still use older chips that have issues.
The best projector will have a high contrast ratio, high brightness and great color. Those are difficult to do at the same time, but as long as the balance works and it looks better than its competitors at a similar price, it’s a winner.
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**As measured. See how CNET tests projectors for details.
