"Gaffer" is a British slang term for "old man," so the sight of that title in movie credits has probably triggered some laughs from moviegoers. But although the idea is funny, this is not a special film job for old fogeys -- the gaffer is actually the head electrician on a movie set. In British theater, the term was used to describe the man who adjusted the lighting, and that came from the city lamplighters who used a "gaff," a pole with a hook on the end, to light the gas lamps in the streets.
Sometimes called the chief lighting technician, the gaffer, along with the key grip, works directly under the director of photography (otherwise known as the DP or cinematographer). The gaffer and key grip handle the physical and technical labor that make the DP's vision into reality -- the gaffer and his or her crew are in charge of lighting, and the key grip's crew work with the cameras. The DP, gaffer and key grip are always in close communication during a shoot. The gaffer's job is definitely a technical and administrative one, but depending on the DP's working style and their relationship, the gaffer can also have some creative freedom with the lighting and lighting effects.
Long before shooting starts, the gaffer goes through the script and makes notes of possible special lighting situations and what equipment might be needed. Then he or she will go with the director, DP, key grip, best boys and producers on a tech scout -- they'll visit the studio and different filming locations to figure out exactly what each scene or shot calls for in terms of lighting, cameras and manpower. Afterward, the gaffer is responsible for writing up -- and sticking to -- a budget for the electric department.
Having a competent, efficient crew is probably the most important factor in making sure that budget isn't blown. The gaffer usually gets to pick his or her own crew, including the second-in-command best boy. During production, the gaffer watches rehearsals to get an idea of what lighting setup will be needed, given the conditions and time of day. The DP might give specific instructions on filters and where rigs and meters need to go, or the directions might be more general -- which is where the gaffer's creativity and judgment come in. The gaffer and crew continually adjust those settings as the scene is filmed, tweaking things between takes. The gaffer and DP will usually watch dailies throughout the day to make sure all the lighting is exactly the way they want it.
Gaffers need to have many years of experience under their (tool) belts as members of the electrical crew, then as a best boy electric. Building relationships in the early years is crucial -- most of the time, a gaffer will get recommended for a job by a DP they've worked with before. Sometimes it also helps to take nonunion jobs as a gaffer before hitting the big time in a union job. The gaffer on a big-budget film generally makes $35,000 to $45,000 for a 12-week shoot. The natural next step up the ladder for a gaffer is DP, although some choose to stay where they are. And as for how many gaffers are actually "gaffers"? Your guess is as good as ours.