The stuff is called cambric and it lets just enough overhead light in so when your house lights are on you can see but it keeps most other light in or out of the room. When you light it on fire it shrivels up but does not ignite. Just to be safe we are spraying it with flame retardant. It does not rip easy (it is like landscape fabric) and it will keep the fog in your room for the most part and still lets air in and out.
Wow, sounds like you've found some great stuff! I'm going to have to give this a try. I'm so tired of putting walls up to the ceiling to keep out the lighting from other areas of the haunt. Thanks for the informatioin!