Adobe After Effects CS4 Visual Effects and Compositing Studio Techniques

Chapter 6. Color Keying

	Slow down, I’m in a hurry.
	--Franz Mairinger (Austrian Equestrian)

Color keying was devised in the 1950s as a clever means to combine live-action foreground footage and backgrounds that could come from virtually anywhere. What was once a fragile and expensive proposition is now fully mainstream; whole films such as 300, now rely on this technique, while the Colbert Report invites anyone with a computer to try the “Green Screen Challenge” (and runs entries from none less than John Knoll).

The process goes by many names: color keying, blue screening, green screening, pulling a matte, color differencing, and even chroma keying—a ...