Masking Concepts
Chapter 18, Masking

Masking is the process of hiding a region of an image. You can use masks to remove the area outside the mask shape and keep the area inside the mask shape, or you can use masks to remove the area inside the mask shape and keep the area outside the mask shape.

Pixel Masking lets you temporarily isolate specific areas of the footage. You can apply effects to the selected area of an image without affecting the rest.