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The U27M90 ships in its Cinema mode, which is very color accurate. A calibration data sheet came with my sample showing results for gamma and grayscale that I could match in my own tests. You’ll soon see that it does not require calibration for a very accurate picture.
Grayscale and Gamma Tracking
Our grayscale and gamma tests use Calman calibration software from Portrait Displays. We describe our grayscale and gamma tests in detail here.
There are no visible grayscale errors in the U27M90’s Cinema or Standard modes. You can see a bit of extra blue in the Balance chart, but all errors are comfortably under 3dE, meaning they’re invisible. The only difference between the two modes is their gamma tracking. Cinema goes for a darker look with gamma around 2.33, while Standard is lighter at 2.11. In practice, Cinema looks slightly more saturated with deeper primary colors. Standard is a good choice for games because mid-tone details are a bit more visible.
To calibrate the Game 1 mode, I adjusted the RGB sliders and left the gamma set on 2.2. That gave me similar results to Standard. The reason to adjust Game 1 is that a PS5 will automatically select that mode when connected. You can bypass this switch by turning Auto Picture Mode off.
Comparisons
For the comparison, I charted the U27M90’s Cinema mode and its default grayscale error of 1.21dE. That puts it in the top tier for out-of-box accuracy. Remember that the X27 costs $1,800. It doesn’t get much better without calibration. After adjusting the Game 1 mode, I got the error down to 1.03dE.
The best gamma performance is found in either Standard or Game 1 mode where the U27M90 showed a light trace averaging 2.11 for a 4.09% deviation. The value range is reasonably tight at 0.14 which is in the top tier. I have no complaints here; these are excellent results.
Color Gamut Accuracy
Our color gamut and volume testing use Portrait Displays’ Calman software. For details on our color gamut testing and volume calculations, click here.
The color gamut tests yielded similar results in the three modes. Cinema looks slightly more saturated due to its darker gamma and on the chart, you can see that all points are on or close to their targets. Magenta is a little off in hue, but this error will be very hard to see in content.
Standard is a little closer and yields the lowest measured error of 2.12dE. Calibration of Game 1 adds a bit of red saturation and puts all colors perfectly in line with their hue targets. The differences I’m talking about are very subtle, so ultimately, users will have to find their preference. The good part is that the U27M90 offers no bad choices.
Comparisons
2.12dE represents the U27M90’s Standard mode. For PC gaming, that’s the best choice. It delivers a bright and colorful picture loaded with sharp detail. When Local Dimming is turned on, contrast and depth are greatly increased. Though it finishes fifth here, this is a strong group of displays, any of which will satisfy.
I measured just under 90% coverage of the DCI-P3 color gamut. Like nearly all wide gamut screens, green is a little under-saturated. Red and blue are fully covered and highly saturated. There is no sRGB mode available, so color-critical apps will need a software profile to rein in the extra volume.
