Grayscale, Gamma & Color
We chose the UP2718Q’s sRGB, DCI-P3, and Adobe RGB modes for our tests. They are the gamuts most commonly used in content production for video, gaming, and photography. As we’ve already mentioned, there are two auto-cal memories available for use with included software. This will let you achieve two perfect presets. Our only complaint is that there aren’t more memories. We’d want at least three to accommodate Rec.709, DCI-P3, and Adobe RGB.
Grayscale Tracking
Our grayscale and gamma tests are described in detail here.
None of the presets are without visible errors. sRGB and Adobe RGB are nearly identical with slight blue issues starting around 40-50% brightness. The DCI-P3 mode has a more obvious green tint. This may not be a problem however. Different versions of the DCI spec vary in their grayscale requirements. When mastering for a commercial cinema, the color temperature should be 6300K, though Ultra HD Blu-ray requires 6500K. To accommodate both, we suggest using the auto-cal software to create a second DCI preset that more closely meets D65.
Comparisons
We couldn’t quite match Dell’s results in our grayscale tests. The included data sheet shows measurements below 2dE when compared to Delta E 94, which is less stringent than our Delta E 2000 standard. And it does not specify which gray levels are measured, only that eight readings are taken. This is a small difference, and we still rate the UP2718Q’s performance as satisfactory.
Gamma Response
Gamma is not adjustable in the Custom Color mode, but you can alter it during the auto-cal procedure. In the presets, we needed a bit of trial and error to determine what standard Dell is going for. In sRGB and Adobe RGB, the reference is clearly 2.2 power function. The UP2718Q meets the trace almost perfectly with just a slight variation at 90%. To the naked eye, there is no visible error.
Several gamma values are included in the DCI specification. The closest match here is to the 2.4 power function. We tried BT.1886 but found it too far off the mark. We also noted that in Rec.709 mode (not shown here), the reference is also 2.2 power function.
Comparisons
All the displays in the group have tight gamma tracking, so the UP2718Q’s mid-pack finish is not a problem. This level of precision results in much better color quality throughout the saturation and luminance range. In the average value chart, we compared DCI-P3 to a reference value of 2.4 as shown in the measurement traces. In all cases, Dell is showing good performance.
Color Gamut & Luminance
For details on our color gamut testing and volume calculations, please click here.
The UP2718Q offers exemplary performance in all its color gamut modes. sRGB and Adobe RGB measure particularly well with almost no visible errors and average values below 3dE. There are tiny hue errors in cyan and magenta, but all points are in contact with the target square, and luminance levels are very close to the neutral level. DCI-P3 mode extends the hue aberration to yellow and is slightly off in its red saturation tracking. Its only visible issues are near the 20% level, but unless you’re looking for the problem, you won’t see it. In all three cases, this is excellent performance.
Comparisons
sRGB and Adobe RGB have no issues worthy of concern, and DCI-P3 is close behind that mark. One could improve upon these scores with the calibration software, but as we’ve already pointed out, there are only two memories available. Most users will be satisfied to simply use the UP2718Q in its Color Space mode and select the gamut appropriate for the task at hand. Few monitors offer this many choices, and fewer still sport such consistent accuracy.
In the gamut volume chart, we’re covering just sRGB and Adobe RGB. The UP2718Q comes close to 100% in both instances but is a tad short on blue. In DCI-P3 mode, we calculated a volume of 88.35% thanks to slight deficiencies in the blue and green primaries.
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