American Cinema: Post 3 - Lighting

Three point lighting can be described as the standard lighting set-up employed in Hollywood. The three points to which the term refers are the dominant sources of illumination - the key light (or chief directional light source), the fill light (or weaker light source that fills in the shadows cast by the key light), and the back light, the minor light that illuminates the space between the back of the set and the characters in order to separate or distinguish the characters from the background. This type of lighting actually employs more than three light sources, (as many as dozens), but gives a look that suggests three light sources. The key light is usually placed in such a fashion as to suggest a realistic light source. It may come from above in outdoor sequences or interior sequences to suggest sunlight or overhead lighting respectively. It may come from the sides to represent lamps as well.
A common type of lighting used in comedies, musicals, and upbeat films or sequences is high-key lighting. This style of lighting uses fill lights to eliminate dark shadows cast by the key light, producing an image that is brightly and evenly lit. Fill lights are even used in situations where it makes little sense for them to be there, such as in a western where the sun in an outdoor environment would realistically produce a shadow under the brim of a cowboy's hat but is eliminated with a fill light.
Low-key would represent the other extreme of lighting. It is found in film noir, suspense, or horror films, in which there is lit fill light, resulting in a dark or shadow-filled image. Whereas high key lighting produces an evenly lit scene, low-key lighting produces a scene that is unevenly lit. Sometimes the norm of its general use is broken as in Billy Wilder's comedies Love in the Afternoon and The Apartment. Although they are comedies they have a bitter-sweet plot that is echoed in the employment of low-key lighting.
Star lighting is the least realistically motivated of the lighting systems employed by Hollywood. Once the foundation of the three point system is set up, star lighting is used to accentuate or conceal certain features of the performers in the scene. It functions to draw the audiences' attention to the performers and heighten the charisma of them. Without realizing it, audiences accept the fact that light seems to eminate from the stars themselves.