Low-key lighting

Low-key lighting is a style of lighting for photography, film or television. It is a necessary element in creating a chiaroscuro effect.^[1] Traditional photographic lighting (three-point lighting) uses a key light, a fill light and a back light for illumination. Low-key lighting often uses only a key light, optionally controlled with a fill light or a simple reflector.

Low key light accentuates the contours of the subject by throwing areas into shade while a fill light or reflector may illuminate the shadow areas to control contrast.^[2][1] The relative strength of key-to-fill, known as the lighting ratio, can be measured using a light meter. Low key lighting has a higher lighting ratio, e.g., 8:1, than high-key lighting, which can approach 1:1.