Amoled display brightness?

[Chiraag]

In Amoled displays, I have heard that when the image on the screen is black, the pixels ate turned off! As amoled displays don't have any backlight , they are self lit pixels. So on increasing the brightness of the phone, why does the black portion of the image also increase in brightness. Shouldn't it say the same(in terms of brightness) as the pixels have been turned off?

 

[jldevoy]

probably light bouncing around under the glass and diffusing across the whole screen.