Matte (filmmaking) - Garbage Matte

Garbage Matte

A "garbage matte" is often hand-drawn, sometimes quickly made, used to exclude parts of an image that another process, such as bluescreen, would not remove. The name stems from the fact that the matte removes "garbage" from the procedurally produced image. "Garbage" might include a rig holding a model, or the lighting grid above the top edge of the bluescreen.

Mattes can also force inclusion of parts of the image that might otherwise have been removed by the keyer, such as too much blue reflecting on a shiny model ("blue spill"), but in this case, technically, they should not be called "garbage" mattes (though they can be created using the same tool).