Lighting technicians place every light in the theater or other venue the places designated by the designer. This is known as the "hang." Once lights are hung, they are plugged into specific circuits that allow them to be controlled by a lighting console, more commonly called a light board. Technicians add color filters, known as gels, and occasionally patterns, known as gobos, to the lights. The lights are then focused not only to aim a certain direction, but also to control each beam for sharpness (clarity of the edge) and, in some cases, shape and size.
A thorough understanding of each type of theatrical lighting instrument is necessary for lighting technicians. They must be comfortable adjusting the instruments quickly, often from high places and precarious positions, such as the tops of rolling ladders. Technicians must also have an understanding of safety procedures to secure the lights so they do not fall and injure anyone.
In addition to the skill of manually manipulating lighting instruments to hang and focus them properly, lighting technicians must read light plots. Plots are blueprint-style drawings of the designer's plan for a show, and each type of light has a symbol and various other notations that are marked on the plot and its accompanying paperwork. Lighting technicians must prepare the lights in a venue correctly from this diagram, often without the designer present until the focus stage of the process.
Lighting technicians are often responsible for maintaining the lighting and electrical equipment in a theater. They perform basic repairs on lighting instruments and electrical cables, and they may be called upon to build special lighting effects or fix and maintain other electrical equipment. An understanding of electrical safety and load capacities (how much power a circuit or wire can handle) is essential.
High school or college technical theater classes combined with hands-on training are a common route to a position as a lighting technician. Internships are valuable for training in professional settings and gaining experience. Once a lighting technician has some professional experience, she can take a test to join the local chapter of the International Alliance of Theatrical Stage Employees (IATSE) to become employable at union-affiliated theaters.