Backlighting (lighting design)
From The Art and Popular Culture Encyclopedia
Backlighting refers to the process of illuminating the subject from the back. In other words, the lighting instrument and the viewer are facing towards each other, with the subject in between. This causes the edges of the subject to glow, while the other areas remain darker. The backlight can be a natural or artificial source of light. When artificial, the back light is usually placed directly behind the subject in a 4-point lighting setup.
A back light, which lights foreground elements from the rear, is not to be confused with a background light, which lights background elements (such as scenery).
In the context of lighting design, The back light is sometimes called hair or shoulder light, because when lighting an actor or an actress, backlighting will cause the edges of his or her hair to glow if he or she has fuzzy hair. This gives an angelic halo type effect around the head. This is often used in order to show that the actor or actress so lit is "good" or "pure". In television this effect is often used in soap operas and has become something of a cliché of the genre. It is also sometimes called the kicker or rim light.
Backlighting helps to provide separation between the subject and its background. In the theatre it is often used to give a more three-dimensional appearance to actors or set elements, when front lighting alone would give a two-dimensional look. In chiaroscuro effects in painting, such as the candlelit paintings by Joseph Wright of Derby (illustration, left), backlighting helps separate subjects in the foreground and emphasizes depth.
A fill flash may be used with a backlit subject to yield more even lighting.
The vertical angle of the back light can change the effect. A low angle could cause the light to hit the camera lens, causing a lens flare. A high angle could cause the nose of the subject to extend out from the mostly-vertical shadow of the head, producing a potentially unwanted highlight in the middle of the face.