All the projectors we review at CNET go through the same testing process that includes objective measurements and side-by-side subjective evaluation. I’ve been reviewing projectors for over 20 years and have used one (OK, many over the years) as my main “TV” since I started reviewing them. I’m also Imaging Science Foundation certified and did training at the National Institute of Standards and Technology to correctly measure displays. I use specialized test equipment, including a C6 HDR5000 colorimeter, a Minolta LS-100 luminance meter and an AEMC CA813 illuminance meter. The data is collected and collated by Portrait Displays CalMan Ultimate software. All projectors are initially set up using their most accurate color temperature and color modes. Test patterns, sent from a Portrait Displays VideoForge PRO 8K, 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 or LED/laser 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.
With 4K projectors, like portable and other home theater projectors, I’m looking for the three most important 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. Therefore, projector contrast ratios are far lower. It’s the difference between a washed-out and “flat” image and one that’s more lifelike and that “pops.” The better projectors will have a measured contrast ratio in the thousands. Most are between 500 and 1,000:1. The median contrast ratio for all the projectors we’ve measured in the last few years is 468:1, and the average, bumped up by several high-priced projectors, is 876:1. Overall light output, measured in lumens, is not only how bright the image is, but how large you can make it and still have a watchable image. A few lumens difference doesn’t matter, but several hundred can be the difference between a dim, boring image and one that really pops. Color is a complex topic, but after years of testing, including dozens of “face-offs” with non-techy and non-reviewers, accurate color almost always wins out over under- or oversaturated color. The most accurate projectors produce lifelike colors that are very natural to watch.
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 and 2,000 lumens, with battery-powered models far less, and some specialized projectors even higher. The average brightness for the projectors we’ve measured over the last few years is 901 lumens.
Color accuracy is the last major factor. No projector can truly take advantage of HDR, Dolby Vision 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, along with devices 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.
For more info, check out how CNET tests projectors.
