Blue-wha?

If you're anything like me, you've probably watched movies that contain sequences of live actors in situations that couldn't possibly be simulated in real life, either on a set or in a real environment. It can be mind-boggling to think of editors working on the film reel frame-by-frame, editing out the backgrounds painstakingly before placing the actors' motions over digital environments.

It's really not all that hard. The answer is a technique called blue-screening; while you're waiting for me to finish the next tutorial, why don't you read a little bit about it?