thumb|Low-key lighting is often used in product advertising. This camera is lit by a [[soft box positioned above, with a white reflector to the front-left|alt=|220x220px]]
Low-key lighting is a style of lighting for photography, film or television. It is a necessary element in creating a chiaroscuro effect. 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.
The chiaroscuro effect the technique often created was also used liberally in classic noir. An example of such a filmmaking choice can be seen in the 1940 film noir Stranger on the Third Floor, which used the lighting contrast to highlight the fantastical qualities of the environment. Chiaroscuro and by extension low key lighting was also used to great effect in German expressionist cinema, widely considered a forerunner of film noir.
Modern neo-noir films such as There Will Be Blood have also employed the tactic to great effect, often using the technique to evoke a sense of unease. Other modern noir-adjacent films and television shows that have used the technique include Joker, The Batman and the films of David Fincher, director of Seven. Fincher in particular makes extensive use of limited light sources, often highlighting an invisible conflict between “light [and] darkness” by effectively controlling the light of his scenes.
Cinematographers such as Roger Deakins also use aspects of low key lighting in their scene composition. In particular, Deakins and others used natural light as much as they could, which often created low key lighting when filmed in low light conditions. Examples of films Deakins has worked on include Blade Runner 2049 and The Man Who Wasn't There. Cinematographer Devan Scott also notes the influence of digital technology in creating these films as well as its increased use in the industry by citing the technology's relative ease of use, and stating that the increase in dark lighting is “a trend enabled by tools” first and foremost.
The proliferation of such techniques has been criticized by viewers in several instances. For example, many viewers reacted poorly to a dimly-lit final battle in the finale of Game of Thrones, despite series cinematographer Fabian Wagner stating that the darkness was intentional, claiming the “show runners decided that [the battle] had to be a dark episode.” Other modern examples of viewer backlash include films such as Arrival and Solo, as well as TV shows such as Ozark and The Mandalorian.