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.
While not the brightest screen of the bunch, the OnePlus One surpasses 400 nits, giving it decent visibility in most viewing environments.
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. It's important to note that AMOLED displays will always measure a black level of zero, since their pixels simply turn off to render black.
The OnePlus One displays a respectable black level, which should help it resolve darker shades of gray and generate richer colors.
The SAMOLED screens in the Note 3 and Note 4 are able to achieve a true black since the organic LEDs are switched off and not emitting any light.
Contrast Ratio
Contrast ratio is the difference between a full white pattern and a full black pattern. Due to their zero reading on the black level tests, AMOLED displays are said to have an infinite contrast ratio.
Contrast ratio on the One is about average, failing to match either the max brightness or black level of the HTC One (M8) or iPhone 6 Plus.
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.
Most of the devices fall very close to the ideal gamma value, but the screen in the OnePlus One gets the closest, better even than the iPhone 6 Plus.
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.
All of the screens come in above the 6500 K value. The OnePlus One and Galaxy S5 are definitely on the higher end of the scale, giving their screens a cooler, bluish hue.
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 OnePlus One falls just shy of covering 90% of the sRGB color space, which is a bit below what other flagship phones are doing today.
Overall, the OnePlus One’s screen is good but not great. The backlight can’t match the contrast ratios or color gamut reached by some of its peers. While it doesn’t post the best numbers, it’s still a nice screen to view and shouldn’t generate many complaints.