Prior to installing the CRT projector, light reflected from the screen that bounced off the walls and ceiling back to the screen was not a big issue. The black levels of my LCD projector were "high" enough above absolute black so that this reflected light did not affect the image.
With the much lower absolute black levels of a CRT projector, this became an issue. If you've ever wondered why so many dedicated home theater pictures you see look like caves, this is why. The walls, floor and ceiling have been made dark to absorb as much reflected light as possible. Reflected light that makes it back to the screen causes the image to look washed out. This is especially noticable when there are a few bright objects against a dark background. If there are a lot of reflections the background will look too light.
This is the theater with some reflection control "tech" installed, see below for the details of what was done.
Click on photos for a larger view.
Frame built for "cabanna" ceiling cover. Made from 8' x 6" x 3/4" plywood planks I had lying around and two 10' x 4" inexpensive base mouldings. I used the moulding because I had it, if I was buying wood I would have used firring strips or 1" x 2"'s.
Completed anti-reflection project. The carpet looks purple, but trust me, it's black. The purple tint is from the digicam. Watching the screen with the lights off there are no distractions. Just the screen floating on the wall...
A scene from lost in space. It really looks this dark. Just a bit of reflected light from the speakers (which are black) and the walls.
Although the space is dedicated to the home theater, the rest of the family didn't like the idea of painting the ceiling and walls anything darker than they already were (which is flat white in the case of the ceiling).
The worst offenders were the light carpeting and the white ceiling tiles. If these areas could be tamed, the rest would likely be acceptable.
I purchased an inexpensive, black, 6' x 9' area rug at Lowes to "kill" reflections from the carpet. I built a 10' x 8' x 8' trapezoid shaped "cabanna" type cover for the ceiling. The fabric used for the ceiling was a flat black suiting material from JoAnne's Fabrics. My wife helped me stretch, sew and attach the fabric.
The overall effect of these changes is quite dramatic, reflections are reduced significantly (I'd judge it to be 70%+). Dark scenes with light areas have more punch to them.
A low cost project that really helped the picture quality and improved the theater experience. If you can paint the room and ceiling right off, that is probably the best solution, but this method works when you need to account for room appearance.
Total cost was $30 for the fabric and $40 for the rug, the rest of the materials were surplus, but would have added another $10 - $20.
I've added some more drapes on the sides and changed out the ceiling tiles near the screen with black ones (bought inexpensive tiles and painted black, now double tiles to improve sound isolation). Also added another black rug. It's really becoming a black hole at that end of the room -- Yeah!