Different Types of Lighting

Available Light: Also known as ambient light. Any source of light not explicitly supplied by photographer for purpose of taking photos. It is light that is already available naturally or artificial light already being used. It does not include flashes however flash lighting provided by other photographers shooting simultaneously in same space is considered available light.

Artificial Light: Any lighting that is not sunlight. It is lighting that is made by man. Examples of these are; fluorescent, tungsten, mercury vapour, sodium vapour, halogen and compact fluorescent. 

Artificial light can be turned on and off by a switch. There are some special types that are used for special processes e.g. infrared heat lamps, ultraviolet lights for tanning etc.

In photography they have different colour temperatures which can be compensated for with filters or simulated with other lighting. 

A flash simulates the light of the sun for a fraction of a second.

Key Light: Most important light a photographer, cinematographer, lighting cameraman or other scene composer will use in the set up of lighting. It highlights the form and dimension of the subject. Key light isn’t a rigid requirement. It can result in giving an effect similar to a silhouette. A number of key lights can be placed in a scene to illuminate moving subjects at specific moments.

Fill Light: In television, film, stage, or photographic lighting, it may be used to reduce  contrast of a scene to match dynamic range of the recording media and record the same amount of detail typically seen by eye in average lighting and considered normal. From that baseline of normality using more or less fill will make shadows seem lighter or darker than normal which will cause the viewer to react differently, by inferring both environmental and mood clues from the tone of the shadows.

Positioning of fill light affects the overall appearance of lighting pattern. When a centred fill strategy is used the ratio is created by overlapping the key light over the foundation of fill.

Backlighting: In lighting design, backlighting is the process of illuminating the subject from the back. In other words, the lighting instrument and the viewer face each other, with the subject in between. This creates a glowing effect on the edges of the subject, while other areas are darker. The backlight can be a natural or artificial source of light. When artificial, the back light is usually placed directly behind the subject in a 4 point lighting set up. A back light, which lights foreground elements from the rear, is not to be confused with a background light, which lights background elements (such as scenery).

In the context of lighting design, the back light is sometimes called hair or shoulder light, because when lighting an actor backlighting makes the edges the subject's hair glow if the hair is fuzzy. This can create an angelic halo type effect around the head. Filmmakers sometimes use this to show that the actor is good or pure. TV productions often use this effect in soap operas, where it has become something of a cliche of the genre. It is also sometimes called the kicker or rim light.

Practical Lighting: Practical lights are light sources that are visible as models within your scene. Outdoors, practical lights include street lamps, vehicle headlights, illuminated signs, and lights on buildings. Indoor examples of practical lights include lamps, light fixtures, TV sets, or any other model you’ve built that emits light.

There are 2 aspects to simulating the illumination from a practical light, You need to light the source itself (such as the actual lamp/lightbulb), and then you need to light surrounding set as if lamp were casting illumination into the scene.