A few weeks ago, we posted a selection of wallpapers ideal for AMOLED displays. The images in question had one thing in common – they were predominantly black – and that’s not only because of the striking contrast achieved by screens of that type. It is a known fact that on AMOLED screens, pixels that are totally black draw no power at all. That is why putting a solid black wallpaper on such a display results in lower power consumption, thus improved device battery life. But at the end of the day, how much power would this save? Surprisingly, not as much as you’d expect.
To test how much battery life I could gain by switching to a black wallpaper, I gathered three phones with AMOLED displays that I had access to – the Samsung Galaxy S7 edge, the OnePlus 3, and the Nexus 6P. Then I set their screen brightness to a constant level – 200 nits when displaying a white image. Normally, a smartphone screen’s brightness fluctuates below and above that point (if auto brightness is enabled, of course), but 200 nits is a reasonable average. Finally, I ensured that no background apps were interfering with my experiment.
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