Bluescreen Compositing

Creating the Plates

9

Let’s stop for a refresher on some vocabulary. Typically, a basic color-based composite is made up of three elements: a background plate, a foreground plate, and the matte, which defines the transparency for the foreground plate. When creating a basic chroma key in a nonlinear editing program, the matte may be invisible (concealed within the effect plugin) but it is there nonetheless. Of course, these three elements are a minimum, because a complex effects composite may have many layers, each with its own matte channel. It’s certainly not unusual to at least have a second foreground layer that is composited over the live action. There may be more than one background plate in certain instances, where the perspective effect ...