Bright green backdrops have been used for decades by the television and film industries to help create certain effects. They were first introduced into movie making in the 1940s. By placing a green screen behind people or objects it makes it easier to isolate them from the background. This allows different elements such as exotic locations and special effects to be added to the shot in post production. The colour green is most commonly used because it differs so drastically from human skin tones. It is also a colour seldom worn by talent. The green background must be evenly lit and showing no shadows for the technique to work. Green screens have become more sophisticated over the years and the improved edge detail makes for almost seamless integration with special effects.