About Masking			Garbage Mask Tool Tabs
Chapter 18, Masking

You can use garbage masks to key undesired elements in an image and to do rotoscope work. A garbage mask affects the image's alpha channel, which is where the transparency information is stored. You can use a mask to create the alpha channel, or you can use a mask to add to an alpha channel.

Garbage matte -- A matte that isolates unwanted elements from the primary element in an image. Garbage mattes are also referred to as garbage masks.

Auto Tangent -- When selected, the mask is created with tangents.

Intensity -- Defines the alpha value defined by the mask.

Opacity -- Defines the transparency of the mask.

Invert -- The area outside of the mask is covered by the garbage mask settings.

Edge Distance -- The inner or outer offset from the edge of the mask.

Edge Position -- The position of the edge handle from the first control point of the mask.

Edge In/Out -- The inner/outer offsets from the edge of the mask.