Chapter 7. Getting Creative with Keys

I think I should explain what this chapter covers before you get any further into it. Working with video layers allows you to create imagery that you cannot create with single-layer video clips. The question is, how do you get shots that are impossible to capture with a camera but that can be built fairly easily and inexpensively during postproduction? I'm referring to shots like having an image over a background that wasn't really there or cutting out parts of an image using a custom shape (like a cookie cutter). This process is generally referred to as creating a composite image. The way to do this is simple: Use alpha channels and key effects.