This blog entry is about the Chroma-Key technique. This is one of the most important techniques in filmmaking. The technique is better known as the Green Screen technique. The technique is relatively simple. A person or an object is filmed in front of a blue or green screen. Then the green or blue back ground can be removed. This removing used to be done with color filters, but nowadays this is done with a computer. When the colored background is removed, a new background can be added.
The first blue screen was used in 1930’s. For instance in the film: ‘flying down to Rio’. The technique was an immediate success, because the blue screen scenes in the 1940 film ‘The thief of Bagdad’ brought the movie the ‘academy award for visual effects’. In this film one of the first travelling matte was made. These travelling mattes were difficult to make, because it was not easy to synchronize the camera for the background, and the camera for the blue screen. This changed when the motion control camera was developed. The motion of the camera was controlled by computers and the both the camera’s could film with the same movement pattern.
So the technique was developed through the ages and used in many movies. The green screen can save an enormous load of time and money. An example of a famous scene that is made completely in front of a green screen is a scene in Star Wars Episode II: attack of the clones. The actors walked on moving ground in a completely green hall, and the background was filled in later.
Chroma key is widely used and the technique is not only used in movies, but also in TV and photography. For instance the weatherman you see in a weather broadcast. It looks like he is standing in front of a weather chart, while he is in fact standing in front of a green screen!