The way I did it - I turned off the lights and took a photo of the monitor at various angles (don't care much about motion blur) Do you observe any color / brightness leakage?
In a brightly lit room I don't see much brightness variation on the screen, but the right side is cyan:(
Every LCD I've ever seen does have some viewing angle issues. This pup is HUGE and yes, if I sit in front of it, I see black pretty cleanly over the my current field of view but moving to one side or the other, to be straight in front of any area, other areas may appear to show this viewing angle issue. I see it on my 2690, my iMac, my Cinema display but they area all much smaller so the effect on a bigger unit is larger because this beast is HUGE. If I'm sitting in the middle of the display, at a distance of about 18-20 inches, the edges are a heck of a lot father from that center position. To get straight in front of say the lower right corner, I have to move my head about 10-15 inches over.
I should probably be a lot farther away from this unit, I have to play some more (and the width of my desk is "only" 29 inches). My god, this display is hugmongous.