Results: Viewing Angles And Uniformity
PLS and IPS are nearly identical technologies, so we expect similar off-axis viewing performance from both screen types. The S27B971D fares well. You can see a little light falloff in the horizontal plane and less in the vertical. The color shifts slightly towards blue as well. The detail of the darkest steps is almost, but not quite crushed. If you enlarge the photo, the difference between the bottom two brightness levels becomes more apparent.
Screen Uniformity: Luminance
To measure screen uniformity, zero- and 100-percent full-field patterns are used, and nine points are sampled. We’re now comparing the results to other monitors we've reviewed.
First, we establish a baseline measurement at the center of each screen. Then the surrounding eight points are tested, their values expressed as a percentage of the baseline (either above or below). This number gets averaged. It is important to remember that we only test the review sample each vendor sends us. Other examples of the same monitor can measure differently in this metric.
First up is black field uniformity.
Screen uniformity is one of the parameters available in the S27B971D’s internal look-up table. You can adjust it using the Natural Color Expert software and an appropriate measuring instrument. Our results are from an out-of-box configuration.
The 8.57 percent result we're showing is excellent, but it would be even better if not for the slight hotspot in the lower-right corner.
Here’s the white field measurement:
Samsung's 1.64-percent result is the best we've ever seen by far for white field uniformity. It even exceeds the values expected from Samsung’s included data sheet! The white field pattern looks absolutely perfect from one corner to the other, with no visible variation in brightness at all.
Screen Uniformity: Color
To measure color uniformity, we display an 80-percent white field and measure the Delta E error of the same nine points on the screen. Then we subtract the lowest value from the highest to arrive at the result. A smaller number means a display is more uniform. Any value below three means a variation that is invisible to the naked eye.
Samsung includes color uniformity on its calibration chart, and our result exceeds that factory measurement as well. Remember, values below three are essentially invisible. A .35 Delta E variation is as good as non-existent. The measured errors range from .12 to 1.07 Delta E.
Unfortunately, when we reviewed Samsung's previous-gen S27B970D, we were not recording color uniformity data. So we couldn't include it in this comparison.