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Sharp PN-K321 32-Inch Ultra HD Monitor Review: More 4K!

Results: Grayscale Tracking And Gamma Response

Our grayscale and gamma tests are described in detail here.

Out of its box, the PN-K321’s white balance runs a bit cool, especially above the 50-percent brightness level. This is a decent result and you could use the monitor uncalibrated so long as you're able to live with a slight blue tint to mid- and high-level whites. We tried the sRGB mode, which locks out color adjustments, and recorded nearly identical results. So, there’s no gain to be had there.

Only an instrumented calibration will produce the above result. You’re looking at perfection. Thanks to the inclusion of low-range RGB sliders, we were able to fix all the grayscale errors. It really doesn’t get better.

Here is our comparison group:

Thanks to solid numbers below 60-percent brightness, the PN-K321 posts a good out-of-the-box average error of 2.88 Delta E. The fact that our winner, Asus’ PQ321Q, uses the same panel demonstrates that a monitor is more than simply the sum of its parts. Engineering and care in manufacturing make a visible and measurable difference.

The calibrated grayscale error falls squarely into the realm populated by high-end professional displays. It’s unfortunate that neither the Sharp nor the Asus have a wide-gamut option. Again, this is pretty much perfect grayscale performance.

Gamma Response

We observed some interesting results in the gamma tests, so we’re showing you the traces for the Standard, 2.2 and 2.4 presets.

The standard gamma setting produces a chart similar to what you’d see when dynamic contrast is in use. The lower levels are made darker and the higher ones lighter to increase perceived depth at the expense of poor detail.

Selecting the 2.2 gamma preset tightens tracking considerably. It’s the same result you’ll see if you choose the sRGB color mode, although doing that locks out the RGB sliders. Aside from minor dips at 10 and 90 percent, this is an excellent chart.

Since the 2.2 preset runs a tad low (too bright), we wanted to try 2.4. It changes the tracking a little and makes things a little darker, but only subtly. It also comes closer to BT.1886. We would use the setting for movies and some games, while sticking to 2.2 for productivity and graphics work.

Here is our comparison group again:

None of the displays in the group have any significant gamma issues. All of them track pretty well with only small variations that can’t be seen with anything but our meter.

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

The 2.2 gamma setting’s result is a tad below 2.2, landing at 2.11. Aside from the 10- and 90-percent levels, the rest of the trace is almost on the line. Again, you won’t really see any problems with actual content on any of these monitors.

Christian Eberle
Christian Eberle is a Contributing Editor for Tom's Hardware US. He's a veteran reviewer of A/V equipment, specializing in monitors.