The shade doesn't really matter, as long as it is neutral. What you're trying to avoid is a brightly colored wall that gives a color cast to the room lighting. If you're shooting low-key studio stoff in the room, black or dark greay is best, but for simple image editing you can go with white or light gray and nothing bad will happen to you.

I am planning to paint my computer office walls a "neutral" gray. I have read that this is a good idea to "absorb light and reduce the risk of color casts." Does anyone have any detailed info on that, like names/numbers of colors. Checking my local paint store yielded a zillion shades of gray. I printed a card of 50% gray from photoshop. It looks fairly dark for walls.  Could I go with a lighter shade and still reap the same benefits.

TIA

Cris Hamilton

Thanks Jonathan for your response! I purchased a "Whibal" and will have my local paint dealer match the neutral gray.