Results: Display Measurements
Brightness
Brightness (also known as white level) measurements are taken by recording the luminance output of each device displaying a full white pattern, with the device's brightness slider set to both minimum and maximum values.
The Shield Tablet takes a step backward from the Tegra Note 7 in maximum brightness. While not ideal for outdoor use, it’s still comparable to other tablets.
In order to make device comparison possible, the rest of our display measurements, along with our battery testing, are performed with the screen set to a standardized white level of 200 nits.
Black Level
Our black level measurement is the luminance output of a full black pattern after the luminance output of full white has been standardized to 200 nits.
The Shield Tablet’s black level is very low, even lower than the high-quality display in the iPad Air. This improves the contrast ratio and overall image quality.
Contrast Ratio
Contrast ratio is the difference between a full white pattern and a full black pattern.
Limited by its max brightness level, the Shield Tablet achieves a reasonable contrast ratio, falling just below the iPad Air.
Gamma
Gamma compensates for the linear brightness levels displayed by a screen, versus the nonlinear way our eyes perceive light. A gamma curve of 2.2 is what we optimally want to see, as a screen with a gamma less than 2.2 appears brighter and with less shadow detail, while a gamma larger than 2.2 displays heavy shadows with fewer highlights.
The Shield Tablet again falls short of the Tegra Note 7, deviating furthest from the ideal value of all the tablets in our chart.
Color Temperature
Color temperature is a measurement in Kelvin, which is used to describe how “warm” or “cool” a given display is. Ideally, as long as you're not viewing your device in direct sunlight, this should be in the 6500 range. Higher color temperatures result in a cool, bluish hue, while lower temperatures deliver a warm or reddish tone.
Color temperature for the Shield is spot-on, improving color accuracy.
Color Gamut
Our volume measurements are compared against both the sRGB and AdobeRGB color gamuts. A reading of 100 percent on sRGB and 72 percent on AdobeRGB is the optimal reading for viewing the vast majority of digital consumer content. A lower reading is typically accompanied by an overly red or yellow image, and a higher reading is usually too blue/green.
The backlight used in the Shield Tablet’s screen is not capable of covering the full sRGB color gamut, unable to even reach an 80% reading. This issue is most noticeable with reds and blues. In practical terms, there will be no color gradation beyond the 77.2% gamut coverage area. Rather than a smooth transition between color shades, you get a solid splotch of color. Apparently, Nvidia was willing to sacrifice some screen quality to hit its aggressive price point.
