We’re always looking to improve how we evaluate different products, and for 2019 we’re adding a whole new category of tests to our phone reviews: Screen performance. While we’ve closely eyeballed all the LCD, AMOLED, Super AMOLED, Retina, and other screens to cross our desks in the past, we are now incorporating full color and brightness measurements in our phone reviews.
We have developed a new screen evaluation process, based on the tests we perform on monitors and TVs. It involves using a colorimeter, image measurement and test pattern software, and analysis based on Imaging Science Foundation calibration techniques.
Here is the full process, and a look at how current flagship phone screens stack up based on our results.
How We Test Phone Displays
Our screen testing is built around the Klein K-80 colorimeter, a device that precisely measures light and color. It’s similar to the Klein K10-A colorimeter we use for testing TVs with one important difference: aperture size. Its frontmost lens is half the diameter of the K10-A’s, which makes it small enough to place against the screen of any smartphone or tablet. The K10-A, while fast and accurate, is a bit too big to measure small screens accurately.
The K-80 connects to a Razer Blade Pro laptop with SpectraCal’s CalMAN 5 software. This software analyzes the data the colorimeter measures and turns it into usable numbers and charts. CalMAN 5 translates the luminance information into a phone’s peak brightness in cd/m2 (nits), and the chromaticity information into X and Y levels for positioning on a color chart. We use the software to produce the color wheels included in our reviews. We also set the software to measure the levels properly based on the screen type; measurements can be slightly different depending on whether an LCD or an OLED is being metered, so we make sure the right mode is set.
Besides connecting to the K-80, the CalMAN 5 software connects to another piece of software on the phones themselves: SpectraCal’s MobileForge app. This is a test pattern generator that produces the lights, colors, and patterns needed to measure each phone’s screen. The app displays the necessary pattern as the K-80 measures peak brightness and various color levels on each phone screen.
We start with peak brightness, which involves measuring how bright the phone screen can get when it’s displaying a full field of pure white. If different display modes are available, we check with each mode to determine the brightest. We then record that peak brightness level in nits and compare it with other phones. Then we move on to color.
The below charts shows all visible color as a range, defined by X and Y values. The triangle inside the charts is the DCI-P3 color space, one of several color space standards that determine the ideal range and levels of colors based on different signal formats and methods. DCI-P3 is currently our standard color space for testing TVs and phone screens, standing as a reachable range that significantly exceeds the Rec.709 standards for broadcast video (which most modern displays can easily reach), but doesn’t hit the Rec.2020 ideal standards for 4K and 8K video (which consumer displays simply can’t reach at all yet).
We record seven measurements for every phone based on the DCI-P3 color space: blue, green, red (primary colors), cyan, magenta, yellow (secondary colors), and the D65 white point (white as viewed under natural, clear daylight). If a phone has a DCI-P3 display mode, we use that. Otherwise, we test any display modes available and determine the most accurate mode with the widest color gamut.
With a color wheel and peak brightness level, we can look at how accurate the phone’s colors are, how wide its color range is, and how bright it can get. We then compare it with similar phones to determine where it stands in its category.
With that explained, let’s look at some of the biggest phones on the market and how they fare in testing.
Apple iPhone XR
Here’s a surprise: The Apple iPhone XR is brighter and has slightly more accurate colors than the higher-end iPhone XS Max. Yes, the less powerful, less expensive iPhone has a better screen with the “color-improving” feature disabled. Greens are still undersaturated, but reds come much closer to their ideal levels, and cyans and yellows are very balanced with magentas running only slightly cool. The most impressive aspect is the phone’s whites, which come within reach of the D65 white point. It’s the best performance we’ve seen from Apple’s Liquid Retina display yet, though some of the Android phones below have superior colors.
On top of all of that, the iPhone XR shows a peak brightness of 592 cd/m2. It’s by far the brightest phone screen we’ve seen yet, with some of the most well-balanced, if not widest, color. Curiously, TrueTone on the iPhone XR skews whites and yellows warmer than ideal, and shows a peak brightness of 556 cd/m2 (which is still brighter than the iPhone XS Max).
Apple iPhone XS Max
The Liquid Retina display on the iPhone XS Max looks good and is very bright, but it isn’t particularly impressive in terms of color. Even with TrueTone turned on, the screen doesn’t reach DCI-P3 color levels. Greens and reds are undersaturated, and both cyans and whites lean toward green. Interestingly, cyans appear perfect with TrueTone disabled, but it results in slightly less saturated greens and a generally cooler look due to the shifting of whites and magentas toward blue.
The iPhone XS Max outright excels at brightness, though. At 544 cd/m2, it’s the second brightest phone we’ve tested so far.
Google Pixel 3
Several android phones show very similar performance to each other. Starting with Google itself, the Google Pixel 3 reaches far past DCI-P3 for greens while slightly undershooting reds. This balance pulls yellows a little bit greenish while keeping cyans accurate. White points are somewhat cool, but not wildly so.
The Pixel 3 is fairly bright, but doesn’t reach the iPhones’ brightness levels. At 400 cd/m2, it’s a little over two-thirds as bright as the iPhone XR and iPhone XS Max.
The OnePlus 6T is almost identical to the Pixel 3 in performance: lots of green reach, slightly greenish yellows, and undersaturated reds. White leans toward cyan, which also reaches past DCI-P3 levels without skewing. Finally, the phone shows a peak brightness of 425 cd/m2, slightly brighter than the Pixel 3.
Razer Phone 2
Lest you think Android phones simply all have skewed whites and wide greens, the Razer Phone 2 demonstates otherwise. It shows the most accurate D65 white point of any phone we’ve tested so far, with balanced cyans, yellows, and magentas. Reds and blues are spot-on, which makes the undersaturated greens easily forgivable. On top of that, it reaches a peak brightness of 533 cd/m2, putting it in range of the remarkably bright iPhones.
RED Hydrogen One
The photographer/videographer-focused RED Hydrogen One is a small disappointment in screen quality. It comes close to, but doesn’t quite reach, DCI-P3 levels, with greens and reds that fall laterally outside the color space to indicate it can show certain greens not in the space but trimming away the edges of the space itself. Yellows are also slightly undersaturated but accurate. Whites are the biggest disappointment, pulling markedly cool and dragging every other color toward blue with it. The phone also shows a peak brightness of 416 cd/m2, settling between the Pixel 3 and the OnePlus 6T, but not coming close to the Razer Phone or the iPhones. Perhaps the phone’s glasses-free 3D screen affects its color and brightness.
Samsung Galaxy Note 9
Finally, there’s the Samsung Galaxy Note 9. For color, it performs similarly to the Pixel 3 and OnePlus 6T, with a remarkably wide reach into greens, tempered by overly cool whites and slightly undersaturated reds. That significant extra green range is notable, because it greatly expands the total number of available colors and lengthens the triangle as a whole. And, while yellow is slightly green, cyan is perfect, so that extra green isn’t skewing too much in any direction.
Its peak brightness, however, is a bit of a letdown. At 311 cd/m2, it’s the dimmest screen of the flagships we tested. It’s still comfortably bright, but as it could be much brighter.
The Best Phone Display
Of the phones tested here, the Razer Phone 2 has the best screen in terms of accuracy. It hits the D65 white point spot-on, and while it doesn’t reach the full DCI-P3 color space, its colors are also remarkably accurate.
For sheer range, the Samsung Galaxy Note 9 and the Google Pixel 3 have the widest reach, but their colors lean toward the cooler side. We tend to prefer accuracy over range, but both approaches have their own merits depending on the content you want to consume.
Screen testing is just part of the suite of tests we run on smartphones. We also look into performance, battery life, and other factors, each with their own separate testing methods and benchmarks. If you’d like to know more about our phone review process, our guide to how we test phones explains the rest of the story.