Just a couple of comments from an old projectionist: If I am repeating something stated elsewhere forgive me. The carbon arcs are still used in some theatres that use reel to reel (2000 feet) projection and not platters. Every time you strike an xenon lamp you lose ten hours life so you need platters or 6000 or 9000 foor reels. The exhaust pipe coming off of the peerless Magnarc lamphouses vent the burning carbon and copper gasses out of the booth. I'd be happy to answer any questions regarding the older machines/booth operation.