- One notable exception to this rule is the follow spot. The follow spot is most commonly referred to simply as a "spotlight" and is the quintessential theater light for illuminating a single actor. However, although the beam from this light is movable, the light itself is placed in a fixed position in a special booth high above the audience. From there, an operator moves the light and turns it on and off during a show.
- Most other lights in the theater are set up in a fixed position (and angle) only for the length of each show and are moved by hand between productions. A trained light technician moves lights such as the source 4 instrument in the diagram above. Although some of the movable lights are more or less complex than this one, the basic rules and process for moving them are roughly the same.
Detaching a Light
- Before a technician can remove a light, she must first get close to it. This may involve climbing stairs or a ladder to access high places in the theater, or it may involve carefully lowering the pipes in the fly system. In order to detach a light, the technician must first unplug the power cable, which is attached to a plug on the pipe. Next, the technician unhooks a safety cable, which is put in place to keep the light from falling if its normal clamp fails. After this, she uses a wrench to loosen the bolt in the "C" clamp that holds the light against the pipe and removes the light.
Attaching a Light
- Once a light is moved to its new location, the process of removal is reversed. First, a technician attaches the "C" clamp to the pipe and tightens its bolt into place (this must be done with a wrench, as fingers cannot tighten it securely enough). He then reattaches the safety cable before plugging in the light's power cord, preparing the light to be turned on.
Positioning a Light
- Once a light is attached, it must be positioned, adjusted and focused for its use in the next production. The light is moved to a position above or below the pipe it's clamped to and locked into place by tightening down the yoke. The angle of the light is similarly adjusted and locked into place at the point where the yoke connects to the "C" clamp.
Focusing a Light
- A light is turned on and its beam is fine-tuned according to the instructions of the light designer. A square of clear, colored plastic (called a gel) is slid into the gel frame holder to give the beam color. The beam is also adjusted in shape, size and focus, but the methods for doing this vary depending on the type of instrument.