The Gaffer is the head of the lighting department. They report to the Director of Photography, and do whatever the DP needs to get the right look for the film.
To be a good gaffer, you need to understand lighting. For instance:
– three-point lighting versus one- or two-point lighting;
– how to diffuse to get soft light;
– how to control hard lighting;
– the difference between a blonde, redhead, kino, and dedo;
– white balance, tungsten or daylight
– how to determine wattage and make sure we don’t blow fuses on set or set off the fire alarms.
Health and Safety is extremely important in this key role.
The Gaffer may have a Lighting Assistant helping them to set up the lights.