ABSTRACT
The earliest electrified theatre-specific fixtures were basically just light bulbs with a shiny surface behind them to reflect more of the light in one direction. Not long after, lenses were added to help focus the light beam down to a more specific shaft of light rather than a simple wash going in all directions. Lenses completed the triad of mechanical parts that make up the core of photometrics as used in a modern lighting instrument. There are a number of different ways to project an image onto the stage using a pattern or slide fitted into the gate area of an ellipsoidal instrument. The most common is to use metal templates, also known as patterns or gobos. Neutral density is a type of filter that reduces the amount of light transmitted without changing its apparent color. Color correction filters are used to change the Kelvin temperature of an incandescent lamp to 56k for film or television purposes.
