Effect of Background Color on Battery Life in Android App
It would also vary with the type of screen, blacks on AMOLED screens do not turn on the cell, so there is no power drain. It's a bit more complicated than the paper suggests. Really the brightness will have far more effect than a colour, unless you are going all white or all black, and even then the screen type and the software rendering will have a huge impact. –  RossC Oct 22 '14 at 10:52