In ancient Greece and Rome, plays were staged outdoors in daylight, usually on a hillside. This tradition continued through the Middle Ages until the 1500s, when theater first moved indoors. Everyday sources of artificial light, such as candles and oil lamps, were first used to illuminate the indoor stage, although their flickering light lacked color and intensity. The systematic development of stage lighting began in Italy during the sixteenth century, when flasks of blue-or amber-tinted water were placed in front of candles and torches to create special effects. Lighting remained uneven and primitive for the next 200 years, and of necessity both the auditorium and stage were lit during performances. The advent of gas lighting in the early 1800s was a major advancement, since gas flames could be controlled more easily and smoothly than candle or torch flames. Unfortunately, they were also hot, malodorous, and caused many...