Illuminations: Why Three-Point Lighting?

Why are we always harping on three-point lighting? You know: key light, fill light and back light? Even when it's done well, it's a cliché and, when badly done, the result is as hokey as a yearbook portrait. Since it's widely used in theater, still and movie lighting, this venerable scheme must have something going for it, right? Of course it does, as we're about to see.

Like many other clichés, three-point lighting became widespread because it was so useful. The idea didn't start in photography, but in theater, where shadows on stage actors make their faces hard to see. Furthermore, shallow sets spread performers out into two-dimensional tableaux. Sound familiar?

To fix the first problem, lighting designers invented warm-side/cool-side lighting, placing yellowish gels over the lights aimed from one side and bluish gels on lights aimed from the other. Since our brains assume that direct lights are from either warm sun or light bulbs, they accept the warm-side lights as "light" and the cool-side lights as "shadow," even though a light meter may show little or no difference between the two sides. Together, warm and cool lights deliver facial modeling without sacrificing detail.

To counter the apparent lack of depth on stage, designers placed a third light above and behind the performers, to dust hair and shoulders with a rim of light. This accent separates the performer from the background and adds visual depth to the stage picture.

Voilá ! Just like that, three-point lighting was…