ABSTRACT
A longer filament generally produces more light energy; the wire is often curled inside the glass bulb so that it can be made longer without using up too much space. Making a bulb smaller in relation to its output is very important for theatre lights, because they are much brighter than ordinary commercial fixtures. A large lamp requires a large fixture, which is problematic when trying to hang many instruments in a small space. One of the problems facing engineers a half-century ago was that the high-wattage lamps used in theatre lights got too hot for the glass bulbs of the period, and they tended to deform from overheating if the filament was too close. To accommodate the heat that was produced, the glass envelope surrounding a 1000-watt lamp had to be several inches in diameter, which was just too big for a practical fixture.
