I'm restarting my school's darkroom. The room I'm using was a darkroom years ago, then it moved, the new one was shut down, and now it's back in the original room. All the equipment is there, developing trays, a Beseler Dichro 45s, plenty of equipment. We even have a few bottles of liquid illford developer, though they're all about 7 years old now so I doubt they're still good. Anyway the big problem is that the revolving door from the old darkroom may not be put in for a while. The spot where it's going is currently completely exposed, just a door frame. So I was thinking of just putting up a double curtain system in order to block out the light in the mean time. What materials would be best for this job?