green screen research (unfinished)

A GREEN SCREEN

Definition of green screen -in film and video techniques such as chromakey) a blue (or green) background in front of which moving subjects are filmed and which allows a separately filmed background to be added to the final image. History- In 1898 Méliès produced a film with a visual trick that would be seen as the beginning of green screen compositing. Blue screen was first developed and introduced in the 1930s.

Mr.Méliès

It was at RKO Radio Pictures. This came after years of using 'travelling matte'which had problems in that the cameras could not be easily synchronized. In early blue screening the dificulties came because they needed a black background with a subject-shaped hole in the middle, called a 'female matte'.In the 1940s Larry Butler used a technique that involved filming the subject infront of a blue background. Blue was used because it was the farthest away from skin tones. He could then create a silloette matte and then using an optical printer to remove the blue background then use the negative of the travelling matte and remove the foreground space of the background plate and then combining the foreground and background together.
The draw backs to this was that there was almost always a thin blue line in the shot and it wasn't very good at handling fine detail like hair and smoke. Vlahose did work on trying to improve this method of compositing. When seperating a matte from a blue screen Vlahose used 'Green cancellation separation and used it with the orginal colour negative and exposing both peices of film together under a blue light to create a blue difference mask. Then a blue separation positive was combined with the orignal negative exposed under a red light to create a cover matte. This matte was then applied back to orignal colour separation but with the blue seperation was replaced by the green and blue difference mask. This was very effective in solving the problems with fine detailing. Using the colour green started to take over using blue in the 1990s as digital equipment started being used. This is because green needs less light, works well outdoors and less commonly used in costumes.

In the Hobbit the look hobbit house interior  has been achieved by using green screen. It was used to save on creating a set which would have been a lot more costly and time consuming, also there are more posibilities of what ti could include by using green screen. I think it was effective and i wouldn't have been able to tell if it was green screen or not.  They have made the shape of the scene they want to achieve and the covered it with green screen so they could put a different image onto itSome objects however, including the chandelier on the ceiling is real this this becuase a character interacts with it and it has to move, it creates a more realistic effect i this is a real prop.