Design Nomenclature / Light & Optics

Key light

Also called key, main light

The dominant source in a setup — the one that establishes the direction of the light, the placement of the form shadow, and the exposure everything else is balanced against. Its height, angle, and angular size fix the character of the image; every other lamp is defined by its ratio to this one.

Plan view: a subject at centre, the camera below it, and a single lamp on the camera's side of the subject and off to the left — the azimuth arc at the subject reading forty-five degrees from the camera axis, its forty-degree elevation given in the sheet beside it because a plan cannot show height.

In practice

Key is a role, not a fixture. The sun, a bounce card, or a window can each be key — whichever source is doing the modeling.

Not to be confused with

How this term connects

Butterfly lightingChiaroscuroFill lightForm shadowHigh keyLoop lightingLow keyPracticalRembrandt lightingRim lightShadow softnessShort lightingThree-point lightingKey light
Related Confused with