"If it can be written, or thought, it can be filmed..." STANLEY KUBRIC
From Encyclopedia PRO
Backlighting is the positioning of the key light either above and behind or completely behind the subject. The intense highlight glow outlines the subject and, because of the contrast that occurs, backlighting creates volume and depth.
In the context of Lighting Design, 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 back light is usually placed directly behind the subject in a 4-point lighting setup.
The backlight 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 affect 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.
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.
Purpose of Backlighting
Backlighting visually separates the foreground object from the background. A backlit object has a large, dark shadow area with a small, strong highlight around it.
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.
Intense backlighting is sometimes used to suggest spiritual and otherworldly encounters. With the use of glow filters and diffusion nets, the effect of the bright highlight around the object is intensified.
Backlights are generally 21/2 to 3 stops higher than the key light to make them stand out. This technique is also used for mysterious and melodramatic effects because of its abstraction of forms and shape. Backlighting is related to rim lighting; they differ only in the way the light is positioned relative to the axis of the camera as well as the subject-tocamera orientation. Both are used as accent lighting to direct the viewer’s focus.