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The Book on Chroma Keying

Chroma Keyingis an old visual effect trick for placing a subject into a completely new scene. Instead of spending large sums of money for highly wrought sets, producers can just opt for green or blue screens, thanks to chroma Keying. Chroma Keying transforms a video footage of a man pretentiously flying in tight harness to a superhero braving the sky to answer a damsel’s cry in distress.

Chroma Keying, otherwise know as blue screen or green keying and color keying, is accomplished by combining visuals from two different sources. The first source is the foreground subject, shot against a blue or green screen. The second source is the background scene and it can be any stock video footage you have of tall skyscrapers in New York or you can cull to recreate the battle of middle earth using CGI (Computer Generated Imagery).

The two frame sources for Chroma Keying are combined, digitally, to replace anything that is blue or green using the analog video during the digital video editing procedure..

Points to Remember in Chroma Keying:

The subject must not wear any of the blue or green screen color, be it his clothes or make-up. If he does, those areas will be replaced with the background image and will be marred with holes in the frame unless you are aiming for the Lt. Dan effect in the movie “Forrest Gump”.

As a general rule, matte will only be good as the camera used to shoot the foreground subject. The foreground video must have a high resolution and a low noise level.

Recommended software for Chroma Keying:

Combustion 4. Offers the new diamond keyer wherein complex chroma Keying tasks are done in a matter of seconds There are presets for luma keying and chroma Keying to give users a headstart. Distinguishing the right transparency range and a higher precision chroma Keying approach are not far-fetched..

After Effects 7. This has some convenient tools for chroma Keying such as a color corrector which removes color bleed and a good matte checker.

Primatte Keyer v 3.0. Chroma Keying is nailed with just a few mouse clicks away. Primatte Keyer conquers matte extraction obstacles including DV & HDV material, uneven lighting, subtle shadows, and reflective spill even prior to compositing.