I suppose any space with matte-black uniform colour would do. I'm not sure what type of lava it is, but if it's not very reflective, then all the light would get "swallowed up".
As part of the "Back-Stage Technical Crew" while I was doing my A Levels, we had a Drama Studio/Theatre (with an expanding tiered seating unit and raised modular staging etc) which was completely blacked out. The whole floor area (about a tennis court but square when the seating was removed) could be completely curtained off with heavy matte-black curtains. The floor was matte-black tiles and a matte-black fine mesh could be drawn across the ceiling lighting rig.
Effectively, it was about as black as you could get. The idea being to experience sounds, and groups of students would do teamwork activities etc without the aid of sight. Communication activities such as building a giant jigsaw (each person was given a piece whilst blindfolded, and then when total darkness, they took off their blindfolds because seeing 'nothing' is different from not being able to see anything (does that make any sense?)
It's interesting how confused you can get when trying to localise point source sounds. Sometimes when more than one point source was used at a time, some students couldn't tell.
There was a thermal imager and IR video camera which was used to monitor the lessons from the control room.
Unfortunately, we weren't allowed to experiment on the students, but while we were setting up, we used the uncovered lighting rig to strobe and play with lasers and spotlights. The air was always a bit dusty, but when the smoke machines and dry-ice was pumped in, it was laser heaven!
I wasn't that interested in flashlights back then. I wish I could recreate the conditions now!
Alastair
