2011

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.
Masking Concepts
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.
Garbage Mask Tool Tabs
The Garbage Mask is a three-tabbed tool consisting of Garbage mask
controls—see
Creating Masks on page 540, Global Composite Output
controls—see
Output Tab Settings on page 558, and the Options tab—see
Options Tab Settings on page 559.
538 | Chapter 23 Masking