Three point lighting consists of three different lights; key light, fill light and back light. The key light is the primary light source, and is used to illuminate the key subject in the frame. these work best if slightly off to the side of the subject, rather than head on. The fill light is used on the darker side of the subject. This can be used to to control the atmosphere and feel of your shot, depending on how bright the fill light is. The back light, or rim light, is used to add another dimension to the subject and is usually the weakest light in a scene.