Theatre has come a long way from the days when “lighting” meant the ability to manipulate or work around the movement of the sun. Now theatres have extensive grids that allow designers to hang and focus tens and hundreds of lights to conjure everything from bright sunlight to a candlelit dinner, and all points in between.
Until fairly recently, if you walked into any given theatre that was setting up for tech, you’d often see a lighting designer up on a ladder on the stage, possibly with an assistant down below. They’d hang one, two, maybe a third instrument and focus all of them on the same area. One area, three lights, each with its own gel—specific colors selected to provide a warm or cool or specialized light, as the case may be.