Slightly off-topic but maybe of interest, a projectionist posted to Reddit:
http://www.reddit.com/r/movies/comments/wxf97/did_you_movie_look_dim_heres_why_bulb_change/
Pics from the bulb change: http://imgur.com/a/OOy8o
What does a projectionist actually do?: http://nesdroc.livejournal.com/123421.html
I run nine screens simultaneously. I'm alone for my usual eight hour shift.