[stryk]

I'd be interested to know what folks in your field think of the newly developed substance [1]'Vantablack'. Thin carbon tubes that apparently absorb 99.965% of visible light. Are there any cool applications for this stuff in practical effects?

1: https://en.wikipedia.org/wiki/Vantablack

[hazeii]

I've been out of SFX for decades so can't speak for current practice; anything really black (classically velvet/black flock) is (was?) useful for hiding all sorts of things from the camera. So I'm just guessing here, but because cameras (more specifically the sensors) are much more limited than the human eye in terms of the range of brightness they can handle it's probably more useful in scientific/direct view applications.