Close Holes

Close Holes

When holes open up in your foreground or background,
the best fi x is usually to take care of these in the individual
Garbage and Core passes; in fact, hole-closing is the main
point of the three-pass method described earlier. The basic
method is as follows:
1. Choke (Garbage matte) or Spread (Core matte) the
holes until they disappear.
2. Spread or Choke (the opposite of the previous step) an
equivalent or greater amount.
This will of course destroy all edge subtlety, which is why it
only works well on a matte intended to be crude and inside
or outside the delicate foreground edges.
Alpha Cleaner, part of the Key Correct set from Red Giant
Software, has an automated tool to do this without destroying
edges, but it can have unintended consequences, fi lling
small gaps that should remain transparent.

Therefore, there are occasions where you have to rotoscope,
usually because the holes are too close to the edge.
It can help to create an animated mask  or
track in a paint stroke.