One of the earliest forms of stage lighting dimming and control was the candle douser. Needless to say, many theatres burned to the ground with this type of stage lighting.
Although the technology has changed, the intent remains the same; control the location and intensity of the light onstage.
Early forms of dimming took the form of increasing the resistance in a circuit. This kind of dimmer (The Resistance Dimmer) creates a great deal of heat and requires a large heavy piece of machinery. In addition, to fully dim a partial load, ghost loads were required. A ghost load was electrical equipment that consumed the remainer of the capacity on a dimmer - usually a light or lights pointed into the wings. In use up to the 1970's, Resistance Dimmers are very hard to find these days.
