In the context of lighting, 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 sometimes called hair or shoulder light, because when lighting a subject, backlighting will cause the edges of his or her hair to glow. This gives an halo type effect around the head.

Backlighting helps to provide separation between the subject and its background.