How Chroma Keying Works?

If you are going to step into the world of Chroma Keying, you need a few things first.

You need foreground footage, for starters. Foreground footage is your subject, and your color screen. You also need background footage, which is the scenery that is going to be replacing the color screen.

The color screen needs to be evenly lit so that it is the exact color all the way across. Shadows caused by poor lighting can wreak havoc on the Chroma Key process. Also, be aware of your foreground subject lighting. It is important to have two separate sets of lights, and to have the subject far enough away from the screen that the foreground lighting will not interfere with the screen lighting in the back.

Once the subject has been properly lit and the background color successfully keyed, it is time to add the new background scene.

When these two are placed together, your actor is suddenly transported from a large blue screen to anywhere you want, the only limits are your imagination, and of course, what kind of film you can get your hands on.


Source: http://www.signvideo.com/