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The Q27G4ZD’s picture modes can be confusing, with both Gaming and Eco adjustments available. I recommend sticking with the defaults, Standard/Standard, for best results. It measures pretty close to the mark with no calibration.
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.
Though the Q27G4ZD’s initial grayscale measurement is 3.07dE, the error is only in red and is barely visible. Neutral white and gray tones will be slightly warm, but other colors won’t be visibly affected. Blue and green errors would be easier to see with the naked eye. Gamma runs a tad light, just under the reference line with an average of 2.13. Since contrast is so high, seeing a problem in actual content is hard.
Calibration brings grayscale tracking to the reference level with all errors well under 1dE. Gamma is mostly the same but slightly higher from 75-100%. Again, this change is very hard to spot in practice.
If you need sRGB for color grading, it is also very accurate with the same grayscale error as before but perfect gamma that rides right on the 2.2 reference. This is excellent performance. I didn’t publish the DCI-P3 chart, but it looks similar and conforms to Display P3, which maintains a D65 color temp and 2.2 power gamma.
Comparisons
The Asus and Aorus are overachievers here with grayscale tracking well below 1dE. The Q27G4ZD is on par with the rest at 3.07dE. This is acceptable given that the error is focused in red rather than blue or green. Calibration puts the Q27G4ZD near the top with a superb 0.39dE result, pipped only by the Philips.
Gamma runs a tight range of values at 0.13, good enough for fourth place. With a 2.27% deviation from 2.2, actual value 2.15, the Q27G4ZD posts an average result in this test. That’s a good thing because no OLEDs have significant gamma issues in my experience.
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 Q27G4ZD’s Quantum Dot technology shows itself in the initial gamut test with slight oversaturation in the red primary and a little bonus green as well. This is a very colorful monitor with a bright and vibrant image. The very small secondary hue errors are fixed with the grayscale calibration. Inner points for all colors are on or close to target. Once calibrated, the error is well below the visible threshold. It doesn’t get much better than this.
The sRGB result is similar, with everything on target except red, which is slightly oversaturated. The error isn’t visible though, with a score of just 1.50dE. The Q27G4ZD easily qualifies as a reference display
Comparisons
With a 1.35dE DCI-P3 color result, the Q27G4ZD takes the win. The others are close though and visually, there’s no difference between 1.35 and 2.73dE. No one will see an issue with any of the screens.
In the volume test, the Q27G4ZD is clearly one of the Quantum Dot panels at 108% coverage but it is a tad behind the others. You’ll be hard pressed to see the difference though, unless the content has a lot of red. This is far from a deal-breaker; it’s really colorful. sRGB volume is ideal at 97.63%.
Test Takeaway: The Q27G4ZD has very accurate color and plenty of gamut coverage that produces a stunning and vibrant image. With calibration, it’s even better, though adjustment is not required for enjoyment. It’s accurate enough in all its available color spaces for critical applications.
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