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Results: Grayscale Tracking And Gamma Response

Dell UltraSharp 24 Ultra HD Monitor: The $1300 UP2414Q
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The majority of monitors (especially newer models) display excellent grayscale tracking, even at stock settings. It’s important that the color of white be consistently neutral at all light levels from darkest to brightest. Grayscale performance impacts color accuracy with regard to the secondary colors: cyan, magenta, and yellow. Since computer monitors typically have no color or tint adjustment, accurate grayscale is key.

At this point, we thought the UP2414Q would respond similarly to the UP3214Q, since it has identical color modes and calibration controls. After considerable experimentation, though, we discovered the two monitors are actually quite different.

For instance, Dell's UP3214Q has an excellent Custom Color mode, which gives you two-point grayscale controls and a color management system facilitating top-notch results. The UP2414Q offers the same controls. However, we recorded inferior numbers in the Custom mode and wound up settling on the fixed Adobe RGB mode as the most accurate configuration.

We’ll let the measurements tell the story.

This is the chart you can expect in both the Adobe RGB and sRGB color modes. You're only able to adjust Brightness and Contrast; grayscale and color gamut cannot be dialed-in. The result isn’t bad per se, but we really do miss white balance controls.

We tried out the available sliders in Dell's Custom Color mode:

This is an excellent measurement run that comes within a whisker of the UP3214Q’s Custom mode chart. Unfortunately, if you want that level of grayscale performance from the UP2414Q, you’ll have to accept some compromises in gamma and color gamut accuracy. Keep reading to see those results.

Here’s our comparison group again:

Our instruments return an error of 2.75 Delta E in Adobe RGB mode, which is a little higher than Dell’s claim of two Delta E, though perhaps this can be attributed to our specific press sample. Other UP2414Qs might measure higher or lower. And really, the error is still invisible. Some monitors do perform better at their default settings. But when the error is under three, you won’t be able to distinguish it with anything but a colorimeter.

What follows are the fixed and Custom Adobe RGB mode results.

Having white balance controls available helps get us an extremely low error of .79 Delta E. That's right up there with the best screens we’ve tested. In the fixed Adobe RGB mode, all we could do was adjust Brightness to our 200 cd/m2 standard level and tweak the contrast so the error remained the same.

Gamma Response

Gamma is the measurement of luminance levels at every step in the brightness range from 0 to 100 percent. This is important because poor gamma can either crush detail at various points or wash it out, making the entire picture appear flat and dull. Correct gamma produces a more three-dimensional image, with a greater sense of depth and realism. Meanwhile, incorrect gamma can negatively affect image quality, even in monitors with high contrast ratios.

In the gamma charts below, the yellow line represents 2.2, which is the most widely accepted standard for television, film, and computer graphics production. The closer the white measurement trace comes to 2.2, the better.

You saw above how great the grayscale tracking was in the Custom mode. This gamma chart is the tradeoff.

The UP2414Q seems to use its Standard mode as the basis for adjustment in the Custom modes. A poor gamma trace is one of the byproducts of that mode. Yes, you can have super-accurate white balance. The trade-off is gamma that is too light in tone throughout its range. After seeing this and the gamut results, I decided the non-adjustable modes are superior.

And here’s the chart in Adobe RGB mode.

Much better, right? That's a trace more befitting a professional-caliber display. It is disappointing to see such a difference compared to the UP3214Q. In all fairness though, the fixed modes, while not perfect, do offer decent performance.

Here’s our test group once more for the gamma comparisons.

The gamma in Adobe RGB mode is pretty much perfect, and that's the kind of accuracy we'd expect from a pro-level tool.

Our test was run in PC mode, which adheres to the 2.2 standard. If you use a Mac, there is preset that changes the gamma to 2.0. The measured tracking is equally flat.

We calculate gamma deviation by simply expressing the difference from 2.2 as a percentage.

With only a one percent deviation from 2.2, this result is within a hair of perfection as well. The biggest luminance error is at 90 percent, where it’s off by only 1.1 cd/m2.

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