Have you ever wondered if your cell phone's screen eats up different amounts of power based on how many pixels of which colors it's displaying? I haven't really either... I mean beside the obvious brightness. But Jeff Sharkey has done just that and has put together a great write-up of just which colors use the most amount of power.
His testing was done on OLED screens but it might apply to other types of screens as well, perhaps we can convince him to do additional testing with other devices.
Either way, the short of the story is that red seems to use the least amount of power. You can click this link for the full story: Jeff Sharkey Android SurfaceFlinger tricks for fun and profit