Dell P2815Q 28-Inch 4K Ultra HD Monitor Review

Results: Grayscale Tracking And Gamma Response

Our grayscale and gamma tests are described in detail here.

This is one of the better out-of-box results we’ve seen. Only a few expensive professional monitors post better-looking charts than the P2815Q. None of the errors are above a visible level. Dell sells several displays with certified factory calibrations. This isn’t one of them, but it performs just as well.

After calibration, we posted slightly better numbers for most of the brightness levels. To the eye there’s no difference. Our only nitpick is that the 20-and 30-percent measurements are virtually unchanged. Dell would have to add a low-range RGB control to make this any better.

Here is our comparison group:

The P2815Q wins the day with an excellent average error of 2.18 Delta E in stock form. It easily earns a place in the “don’t need to calibrate” category.

By making a few adjustments, we reduced the average error to 1.45 Delta E. With the 18-percent contrast reduction, calibration is hard to justify, at least with our particular sample.

Gamma Response

It’s rare that we measure much change in gamma after a calibration. Most monitors only have presets, so there’s typically little control available. The P2815Q has no gamma adjustments at all. Yet, we observe a visible improvement. The pre-cal chart shows a too-light curve with less-than-ideal tracking. The luminance errors grow slightly as brightness levels rise.

After calibration, the curve looks about the same. But it’s much closer to 2.2 than before. Like the grayscale results, this isn’t a huge gain. However, if you’re after ultimate accuracy, it may be worth it to calibrate and sacrifice a little bit of contrast performance.

We return to the comparison group for the gamma tracking and deviation results:

The race is fairly tight, so a fifth-place finish is by no means poor. A .16 range means pretty tight tracking. The values range from a high of 2.24 to a low of 2.09.

Here are the deviation results:

With an average value of 2.15, the P2815Q comes pretty close to the 2.2 standard. We wish there were a few extra presets available so we could choose darker and lighter options based on content. Some games benefit from a lower (brighter) gamma, while film content can be mastered using BT.1886, which requires a higher (darker) setting.