Video Production/Video Directing Tips and Tricks: "Three-Point Lighting"

Three-point lighting, also known as triangle or photographic lighting, utilizes both directional and diffused lighting to obtain the best results.

The main light, or key light, is positioned slightly above and to one side of the camera from the key light. It reduces the shadows (made by the key light) but should not eliminate them. The fill light also reduces the lighting contrast. The more the key light is offset, the more important this soft fill light (also known as filler or fill-in) becomes. If the key is nearly frontal, you may not need a fill light at all.

Finally, a back light is angled down onto the subject from behind to give some separation between the subject and the background. The back light emphases the shape of the subject.

The key light and back light are generally the same intensity. However, the back light may need to be reduced due to light hair color. The fill light is usually one-half or three-quarters the intensity of the key light  and back light.

Wherever possible, additional lights can be used to illuminate the background behind the subject. But where space or facilities are limited, spill illumination from the key lights and fill lights may be used to cover the background areas.

- Television Production by Jim Owens and Gerald Millerson, 15th Edition.