Chroma key compositing is a technique for layering two images together. A color range in the top layer is made transparent, revealing another image behind. The chroma keying technique is commonly used in video production and post-production. This technique is also referred to as color keying, color-separation overlay (CSO; primarily by the BBC[2]), greenscreen, and bluescreen. It is commonly used for weather forecast broadcasts, wherein the news presenter appears to be standing in front of a large map during live television newscasts, but in a television studio it is actually a large blue or green background. The meteorologist stands in front of a bluescreen, and then different weather maps are added on those parts in the image where the color is blue. If the meteorologist wears blue clothes, his clothes will be replaced with the background video. This also works for greenscreens, since blue and green are considered the colors least like skin tone.[3] This technique is also used in the entertainment industry, for example for special effects. Software is available today, such as Pinnacle Studio, which makes it possible and relatively easy for the average home computer user, to create videos using the Chromakey function and greenscreeens.
