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The PG27UCDM includes factory calibration data, and my tests confirm its out-of-box accuracy. In the default Racing mode, it does not need calibration. It also has an accurate sRGB mode and plenty of image controls for those who want or need to tweak.
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.
The only flaw in the PG27UCDM’s default chart is light gamma tracking. Grayscale is visually perfect with all values below 2dE. But gamma is a bit under the reference line with a 2.11 average. This is hard to spot in content, but with so much contrast available, a darker value will add texture to the image.
I calibrated the user color temp with its precise RGB sliders and achieved better grayscale tracking and improved gamma. It is now exactly on the line with a 2.2 average. It can’t get better than that.
The PG27UCDM has two ways to select sRGB. You can choose the sRGB Cal mode from GameVisual or retain calibration ability by simply sticking with Racing mode and picking the sRGB option from the Display Color Space sub-menu. The result is visually perfect grayscale and decent gamma that’s marred only by light values from 70-90%. This is still well within tolerance which makes the PG27UCDM qualified for color critical applications.
Comparisons
The PG27UCDM’s 1.23dE default grayscale is certainly impressive, but so is that of the other screens. None of them require calibration. These monitors are expensive. but their performance and accuracy justify the price. Calibration makes slight improvements across the board but visually, the differences are invisible.
The PG27UCDM manages better gamma results than all but the Dough, which has a slightly tighter value range. Errors are well below the visible point. All the monitors are super close except the Aorus, which runs a bit lighter than the rest.
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 PG27UCDM measures like other QD OLEDs with full coverage of the DCI-P3 gamut, plus a little bonus red. There is slight oversaturation, which is easy to spot in SDR content but nearly impossible to see in HDR mode. Hue and saturation points are all on or close to their targets. With a 1.60dE score out of the box, the PG27UCDM is visually free of errors. Calibration tightens up hue tracking a bit, but the visual change is minuscule.
The sRGB gamut option is also visually perfect with no points outside the target box. The PG27UCDM is fully qualified for color grading to DCI-P3 and sRGB specifications.
Comparisons
It would be easy to say it doesn’t get much better than the PG27UCDM’s 1.28dE color score if there weren’t four other monitors that measured lower. This is impressive performance, and it speaks to the consistent quality of the 4K OLED category, in which I have yet to see an underachiever.
In the volume test, it’s easy to spot the Quantum Dot panels. They’re the ones with over 100% coverage, like the PG27UCDM’s 103.27% score. The Aorus and HP screens have slightly greater volume, but this is a small difference in practice. You also get near-ideal sRGB coverage of 97.89%. If you’re looking for maximum OLED color, there are a few QHD screens that deliver around 110%, like the recently reviewed Samsung OLED G6 at 112%.
Test Takeaway: The PG27UCDM makes good use of its Quantum Dot panel with some bonus red, but its accuracy is what makes it a compelling choice. It doesn’t need calibration, and it is spot on for both sRGB and DCI-P3 mastered content. With extensive adjustment options, it’s well suited for tweakers. Color-wise, it is essentially flawless.
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