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Results: Brightness And Contrast

NEC EA274WMi Monitor Review: Eco-Friendly At 2560x1440
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Uncalibrated

Before calibrating any panel, we measure zero and 100-percent signals at both ends of the brightness control range. This shows us how contrast is affected at the extremes of a monitor's luminance capability. We do not increase the contrast control past the clipping point. While that would increase a monitor’s light output, the brightest signal levels would not be visible, resulting in crushed highlight detail. Our numbers show the maximum light level possible with no clipping of the signal.

Our comparison group includes the last six monitors reviewed at Tom’s Hardware. The Asus PQ321Q, Dell UP3214Q, and UP2414Q are Ultra HD displays. The Samsung S27B971D is an sRGB panel with QHD resolution. And the ViewSonic VP2772 is a wide-gamut display, also QHD.

The max brightness result is measured in the EA274WMi’s Standard picture mode using the Native color temp preset. Contrast is set halfway through its range (50 out of 100). You can get a little more light by upping the slider, but clipping starts at 51. The result is a little higher than the panel’s rating of 350 cd/m2.

Our measured black level is pretty good, given the panel’s high brightness.

When the backlight is on full, most monitors won’t deliver a decent black level. NEC lands mid-pack; the EA274WMi is about average for our last 22 screens tested.

The resulting contrast ratio isn’t too bad thanks to a high white level.

The EA274WMi comes in second in this fairly expensive group. You could easily use it outdoors in bright sunlight and see a pretty decent image. Photographers on location might want to consider a display like this.

We believe 50 cd/m2 is a practical minimum standard for screen brightness. Any lower and you risk eyestrain and fatigue. Some monitors like the EA274WMi will measure under that level. We recorded a very low white level of 13.7128 cd/m2 with the backlight turned all the way down. This is a bit too dim for practical use. Raising the brightness to 12 gets you 50 cd/m2 with a black level of .0625 cd/m2 and a contrast ratio of 788.4 to 1.

Our measured minimum black level trounces the other monitors in the group, but that is mainly because of the extremely dim backlight. At 50 cd/m2 max, the black level would put NEC in fifth place, which is an otherwise typical performance for a 27-inch QHD screen based on an LED-lit IPS panel.

The contrast ratio is starting to look more like the rest.

The minimum contrast ratio drops around 22 percent from the max number, yielding a decent result (even if it's less consistent than the last few monitors we tested). The other five in this group all measured closely in their maximum and minimum contrast tests. Hopefully, the calibrated result will be somewhere in between.

After Calibration

Since we consider 200 cd/m2 to be an ideal point for peak output, we calibrate all of our test monitors to that value. In a room with some ambient light (like an office), this brightness level provides a sharp, punchy image with maximum detail and minimum eye fatigue. It's also the sweet spot for gamma and grayscale tracking on some monitors, which we'll consider on the next page. In a darkened room, many professionals prefer a 120 cd/m2 calibration. We find it makes little to no difference on the calibrated black level and contrast measurements.

To calibrate the EA274WMi, you have to use one of the four adjustable color temp presets. We went with number three and the result is an excellent black level.

Calibration often raises the black level from its out-of-box state. But the EA274WMi doesn’t suffer from that phenomenon.

As we hoped, contrast is a little better after calibration than before. We’re now at over 800 to 1.

We’ve seen several monitors achieve better than 1000 to 1 contrast after calibration. However, the only screen that did this recently was Dell's UP3214Q. The NEC comes closer to that elusive figure than the other four screens in our group.

ANSI Contrast Ratio

Another important measure of contrast is ANSI. To perform this test, a checkerboard pattern of sixteen zero and 100-percent squares is measured, giving us a somewhat more real-world than on/off measurements because it tests a display’s ability to simultaneously maintain both low black and full white levels, factoring in screen uniformity. The average of the eight full-white measurements is divided by the average of the eight full-black measurements to arrive at the ANSI result.

The ANSI value is a little lower than the on/off one, just like every other display that’s been in our lab. Obviously this is an extreme test. As mentioned, though, it's also more real-world. Intra-image contrast is what we see in a typical image. In the case of the EA274WMi, the drop is less than nine percent. I consider that to be excellent.

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