[Rinehart]

Arc lamps were very rarely used, since they had a number of drawbacks: the characteristic buzzing sound, the fact that they are DC equipment, and that from time to time they had to readjust or replace the carbons, not easy to do on the fly. They did use them at the BBC, and performers were told that if suddenly the light went out, because they had to fix the carbons, to "fake it and force on."