Research and understanding green screen

A green/ blue screen is a special effects film technique involving filming actors against a blue/green screen on which effects such as computerized graphics can be added later and integrated into a single sequence. The green or blue screen is usually used to film the impossible; graphics that are so high maintenance to create in real life such as: cars exploding, a un-natrual world scene/atmosphere ect..
When special effects were first introduced in the 19th century a man called George Melies, he created a film called 'Four heads are better than one' he used a visual trick which was the very beginning of what we now believe is 'green screening' This film was created in the year of 1898.
http://www.youtube.com/watch?v=RzsdqsiJQ6Y

He did this by combining multiple shots together into one and this then resulting in a successful 'illusion' to the viewer. They called this the 'matte' shot, which was the very first visual illusion on television to be created. From then on this 'trick' was no longer used to create comedy for the viewer but slowly developed into more serious clips to make a scene more believable or impossible. After this, the effect called “black back matte” which was called the Williams Process was used quite famously by John P. Fulton in 1933 for the film “The Invisble Man”. The shots where the invisible man was taking off his clothes were accomplished by photographing actor Claude Rains wearing a full black velvet suit standing against a black background. This effect was so memorable and startling it was used on follow up sequels even after more effective processes came along. 

The Williams Process had some issues – for one, any shadows on the subject would be lost in the traveling matte. An alternative came about in 1925, invented C. Dodge Dunning which would eventually be called the Dunning Process

This technique produced some of the best travelling mattes of the time and was used by Disney first on film The Parent Trap and then The Absent Minded Professor both in 1961. Mary Poppins in 1964 demonstrated the capability of the sodium vapor process winning an academy award for best special effects. After all of these processes took place, the digital camera became more complex then linking with different softwares and products to create a life like special effect picture.