Results: Grayscale Tracking And Gamma Response
A 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.
Given the S27B971D’s factory calibration and correspondingly-higher price, we are a little disappointed by the screen's out-of-box performance. We measured each picture mode and came up with similar results for all of them. There is a calibration data sheet included in the box. However, we couldn't duplicate those numbers without adjustment. You can see the color temp runs a little green as brightness rises. Errors are visible after the 50-percent mark.
Fortunately, a high-quality calibration is fairly easy.
This is a stupendous result, to say the least. The errors range from .11 to .98 Delta E, proving that a properly designed display can make do with just a single-point white balance control.
Here’s our comparison group again.
At default settings, the S27B971D is below average in grayscale performance. The S27B970D was only a little better.
After calibration, the 971 rockets to the top of the chart, besting its predecessor by almost .30 Delta E. Its .42 value is the best we’ve recorded to date for any display of any type.
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 negatively affects image quality, even in monitors with high contrast ratios.
In the gamma charts 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.
This graph was generated before we noticed the incorrect HDMI Black Level setting. We're not sure why Samsung has this at Low by default. Not only it hose the gamma curve, but it also crushes both highlight and shadow detail noticeably.
This is the gamma measurement at the Normal setting. It’s even better, if only slightly, than the graph generated by the S27B970D. Aside from a tiny dip at 10 percent, it’s perfect. And that dip represents a measly .33 cd/m2.
Here’s our test group again for the gamma comparisons.
A value range of .14 indicates extremely tight gamma tracking. And that is caused by only a single aberration at 10-percent brightness. As you can see, it doesn’t get much better.
We calculate gamma deviation by expressing the difference from 2.2 as a percentage.
Only three other displays we’ve reviewed can match this result: AOC’s I2757FH, HP’s ZR2740w, and Asus’ PB278Q. For all intents and purposes, this is perfect gamma response.
