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Results: Grayscale Tracking And Gamma Response

Dell P2714T 27-Inch Touchscreen Monitor, Reviewed

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.

With the exception of the 100-percent brightness level, we're shown a fantastic out-of-box result. This is the P2714T’s Standard picture mode with brightness and contrast set to their defaults. The light output at 100 percent is just over 192 cd/m2, well into the usable range. You could unpack the monitor, turn it on, and never touch a single control, and you’d have an almost-ideal image.

Of course, we can’t leave hardware well enough alone. We set the picture mode to Custom Color and performed our usual grayscale calibration.

It just doesn’t get any better. In addition to slight tweaks of the RGB sliders, we lowered contrast and raised brightness to bring the 100-percent brightness level in line with the rest of the scale. In exchange we get exceptional performance from the screen (which seems to be the case whether you calibrate or not).

Here’s our comparison group of the last six desktop monitors reviewed here at Tom’s Hardware.

The P2714T boasts an out-of-box result better than some displays manage after calibration. The average figure of 1.72 represents a high Delta E reading of 4.26 and a low of 1.11. The high number is at the 100-percent signal level. The next highest error is only 2.03!

But there's more; white balance is even better after calibration.

An average measurement of .86 Delta E places the P2714T in the company of products designed for professional photo use. If it had a wider Adobe RGB 1998 gamut, it would fully qualify. The fact that we only had to make tiny changes to achieve this result is even more amazing.

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 chart 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.

The gamma tracking shows a slight dip from 40 percent brightness on up, meaning those signal levels are a little too high. The actual error is no greater than 4 cd/m2.

Here’s our test group again for the gamma comparisons.

You can see the P2714T’s gamma tracking is pretty flat. A value range of only .16 verifies that result. Even though its contrast is not exceptional, the image still looks three-dimensional and punchy thanks to consistent gamma response.

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

Dell remains in the top tier of monitors for gamma response with its tiny 3.18-percent deviation from the 2.2 target value. We’re glad to see more and more companies making accurate grayscale and gamma a priority. The differences between screens has become smaller and smaller in just the past year or so.

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