Originally Posted by Herc
I'm not convinced of the benefits of creating the darkest blacks because your iris will open up when the image gets dark.
I can say that after a bit of experimenting with different flat greys in a very light-controlled room (both in the dark and with different lights-on situations), I agree pretty strongly with this above statement.
The dark and darker greys gave no real benefit toward black-level, after a couple seconds of eyes adjusting to the screen black bars were equally visible as they are on a flat-white screen. This surprised me because I'd read the light level at which we can detect nothing darker is roughly 0.00087 ftL and I'd made VERY sure to be darker than that by the end..even so, seconds later I could still see black wasn't pitch-black and so could others.
There ARE also problems with going darker. The eye can see more contrast variations within the brighter range, so a contrast figure that stays the same will actually look slightly higher-contrast if it is brighter.
While black levels aren't helped, shadow detail IS harder to make out on a darker surface. Once again, the visible contrast range is shrunk so your eyes perceive a flatter, less contrasty shadow detail.
Color perception can also be weaker on a darker surface which also hurts shadow details (dark scene made even darker..less visible contrast AND less visible colors).
Add to all this that you need to keep a certain level of brightness compared to your surroundings or else you'll end up noticing your projected whites are grey. I was working with a relatively dim projector so I had to black-out my walls and ceiling to get my eyes to stop noticing that the white walls were looking too bright compared to the lighter scenes on-screen.
So, in my case, the dark (low gain, flat) screens offered no benefits, but did have small disadvantages (lacking detail, less vibrant color, finicky perception of white depending on any bright surface in peripheral vision) especially as I went darker.
In the end I went back to flat white. I regret nothing and am happy for the experience.
This is all pertaining to flat, natural-gain screens. Ambient light rejecting screens are a completely different story.