Bluescreen/ Green Screen Compositing

There are many situations where placing an actor in a scene for real would be too
expensive, too dangerous, or even physically impossible. In these situations, you
would want to fi lm the talent in an inexpensive and safe environment, then later
composite them into the actual expensive, dangerous, or impossible background.
This is what bluescreen compositing is all about. The talent is fi lmed in front of a solid
blue background to make it easier for the computer to isolate and then composite
them into the actual background as shown in Figure.

Bluescreen compositing offers a completely different set of challenges than CGI
compositing, because the compositor must fi rst isolate the talent from the backing
color by creating a high-quality matte. This matte is then used to perform the composite,
whereas with CGI, a perfect matte is automatically generated by the computer
and comes with the CGI image.

The backing color can also be green, in which case it is called a greenscreen, but
the principle is the same in either case. The computer detects where the backing
color is in each frame and generates a matte that is used to composite the actor (or
spaceship, animal, dazzling new consumer product, or whatever) into the background.
This is where the artistic and technical challenges to the compositor skyrocket.
Not only because of the difficulty of creating a good matte, but also because
the various elements will not visually match the background very well so they must
be heavily color corrected and processed by the digital compositor to blend them
properly.

Green

 Green Screen Photos...