question on screen

[bl4ke360]

I decided to see if the blacks on this oled screen really are pitch black, so I loaded a picture with a 100% solid black color, I went into a room with all the lights out, absolutely pitch black, to see if the screen would emit any light at all. I also covered up the lights on the physical buttons just to make sure of no light leakage from them affecting the screen. But the screen actually did seem to emit light, a little bit, but technically it shouldn't, right? Why is the screen not pitch black when the pixels should be off when displaying a black color? Of course this is only noticeable in pitch black places but does this happen to everyone else too?