For all text based reading applications it is a really good idea to set the standard Black text on a White background to Reverse Video, White text on a Black background. Not only does that use a lot less power but it improves screen viewability in bright Ambient Lighting. Start by setting Googleâ€™s search page to a Black background. Do the same for Email and other Apps and websites wherever possible.
White text on black background for all applications that are text centric.
A more subtle but more important issue is that color has a major impact on display power consumption because the Green OLEDs provide 10 times more Brightness per watt than Blue OLEDs. In fact, Blue OLEDs consume more power than Green OLEDs but deliver only about one tenth of the Brightness. So give preference to images and wallpapers with Greens and try to avoid images with lots of Blue.
Landscapes, plants, asparagus, green apples, pees, and frogs like Kermit.