4-point lighting setup

4-point lighting is one of the basic setups to light a scene. It could be used for a simple interview (single subject) or a factory shot with tens of subjects. The term comes from the use of four lighting sources:

1 - Key light

2 - Fill light

3 - Back light (Additional terms include shoulder/hair light or kicker)

4 - Background light

The setup starts with setting up the Key light to light the subject(s). Determining the position of the key light is of primary importance as the key light usually governs the scene. Once the key light is in place, areas of shadow will appear on the subject(s) which usually requires a fill light. A fill light will add modeling and decrease the contrast of the scene.

The back light is placed next usually behind the subject(s) and at an angle. The purpose of the back light is to add a contour to the subjects especially the shoulders and the hair which will separate them from the background.

The background light is placed behind the subject(s) or alternative very high (on a grid) or a very low and it provides illumination to the background. The problems that the background light solves are twofold: on the one hand, it eliminates the shadows of the subject(s) that may have appeared on the background; on the other, it makes the background stand out.