Here are my thoughts on Neil's problem...

GAUZE (Recommend "Sharks-tooth" pattern)
Cost :- Relatively dear.
Size :- Comes in up to 36 feet (1097 cm) widths!
Weight :- Fairly light weight (Compared with canvas for instance)

Rigidity :- Now here it gets interesting. As it's just a thin flimsy material it has to be sup-
ported in some way. We used it as a "curtain" hung from a track and weighted at
the bottom. The sides were stretched as tightly as possible. However if it's a "forest"
scene painted on a gauze it's best if it is NOT drawn tight when hung, but let the
natural folds help the 3D effect of the trees/foliage.

Fireproofing :- Comes already fireproofed, but must be retreated once wetted.

Sealing :- Yes definitely needs sealing before painting. Try laying plastic sheeting on the
floor then the gauze on top to seal and paint it. I “raw bolted” a wooden frame to the floor
to which I nailed the edges of the gauze. Don't make too strong a solution of
sealant otherwise you will block up the netting holes and destroy the illusion.

Painting :- For painting a gauze I suggest you use well diluted theatrical paints supplied for
the job. Household emulsion will clog up the holes in the net. Beware, theatrical paint is very very expensive. However, a little of it goes a long way as it still retains its colour even when diluted up to ten times, but you have to buy the colours in the first place and that is where the expense comes in.

Drawbacks :- Cost (see above) Also it is unlikely you will be able to repaint it for another show.

Don't forget it is best to hang a black drape directly behind the gauze and pull this away at the last minute before the lights are brought up behind. That way there won't be any annoying tell-tale sparkles as people move about behind, catching any light spill from the front.

Gauzes rarely work well on a small stage especially if it is a "front cloth" which covers the whole of the proscenium arch. Small vignette gauzes work alright - such as the end of Brigadoon where the man is dreaming in the American bar about being back in Scotland and the image "comes up" behind a small gauze which is part of the set. A full front-gauze works well in the Royal Opera House but not in the local hall. Unless you have an extensive lighting rig with great control of the illumination, on a small village hall or school stage there is inevitably spill from lights (even the exit lights in the hall) and the effect is ruined.

Gauzes are best used for brief transformation events otherwise the audience will get impatient and feel they "can't see properly" if the scene goes on for too long behind this veil.

Where to buy an unpainted gauze? Many companies supply this material. But I suggest you first try the Yellow Pages for your nearest Theatrical Supplies. Failing that then try the search engines on the web. Try "Stage Drapes" or "Stage Draperies"