Lighting for portraiture
Three-point lighting One of the most basic lighting plans is called three-point lighting. This plan uses three (and sometimes four) lights to fully model (bring out details and the three-dimensionality of) the subject's features. The three main lights used in this light plan are as follows: Key-Light
Also called a main light, the key light is usually placed to one side of the subject's face, between 30 and 60 degrees off center and a bit higher than eye level. The purpose of the KeyLight is to give shape (modelling) to a subject, typically a face. This relies on the first principle of lighting, white comes out of a plane and black goes back into a plane. The depth of shadow created by the Main-Light can be controlled with a Fill-Light. Fill-in light
In modern photography, the fill-in light is used to control the contrast in the scene and is nearly always placed above the lens axis and is a large light source (think of the sky behind your head when taking a photograph). As the amount of light is less than the key-light (mainlight), the fill acts by lifting the shadows only (particularly relevant in digital photography where the noise lives in the shadows). It is true to say that light bounces around a room and fills in the shadows but this does not mean that a fill-light should be placed opposite a key-light (mainlight) and it does not soften shadows, it lifts them. The relative intensity (ratio) of the Key-light to the fill-light is most easily discussed in terms of "Stops" difference (where a Stop is a doubling or halving of the intensity of light). A 2 Stop reduction in intensity for the Fill-Light would be a typical start point to maintain dimensionality (modelling) in a portrait (head and shoulder) shot.