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Results: Gamma And ANSI Contrast Ratio

VP2770-LED Vs. S27B970D: 27" Monitors At 2560x1440
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Gamma

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 greater depth and pop. Meanwhile, incorrect gamma can negatively affect image quality, even in monitors with high contrast ratios.

We’re now including the gamma tracking charts for all the monitors we test. The yellow line represents 2.2. The closer the white measurement trace comes to 2.2, the better.

The VP2770-LED sticks pretty close to the 2.2 mark. There’s a slight drop at 10 percent, which means the monitor renders that signal level too bright. The rise towards 90 percent means the signal is slightly dark.

Samsung's screen measures slightly better in this metric.

Aside from slight dips at 10 and 90 percent, the S27B970D displays perfect gamma tracking. This is excellent performance.

You can see from the comparison charts that both panels measure extremely well, coming very close to the 2.2 value.

The ViewSonic achieves its best gamma at the Standard setting, while the other two presets are either lower or higher than 2.2. Samsung includes settings for every gamma value from 1.6 to 2.7, and each one measures correspondingly to that value.

Because some monitors fluctuate at different points in the brightness range, we also include the range of gamma values. A lower range number indicates superior gamma tracking.

Both monitors render near-perfect gamma. A range of values that low is invisible to the naked eye, indicating an extremely well-engineered display.

ANSI Contrast Ratio

Another important measure of contrast is ANSI. This is a relatively new benchmark for our monitor reviews. To perform this test, a checkerboard pattern of sixteen 0 and 100 percent squares are measured. This is 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, and factors 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.

Our result is not entirely surprising, given that both panels maintain lower than average on/off contrast ratios. The previously-tested FHD panels did a little better. Even though the VP2770-LED has a slightly higher on/off number, its ANSI measurement is a little lower than Samsung’s.

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