The interesting thing about Android is it can sometimes behave differently, even on the same hardware. Here is a video playing on 2 Galaxy Nexus phones, the top is using Android 4.1(Jellybean), the bottom is using Android 4.0(ICS). When both phones are using the same auto brightness option, the phone will give a slightly different colour, note the individuals jacket. Nothing you can do here as many different phones have very different brightness options, but something to keep an eye on when testing. Hopefully the user will never notice….