Apple Final Cut Pro 5 - Manual (Page 1188)

Chapter 19 Keying, Mattes, and Masks 401
II
7 Depending on how the edges of your foreground subject look, you may want to make
adjustments using the Edge Thin slider. The Edge Thin slider allows you to shrink the
alpha channel created by the Chroma Keyer to begin to eliminate the light fringing
that remains around the edges of the foreground subject.
8 An optional step at this point is to use the Softening slider to blur the edges of the
foreground subject. This is especially helpful if the edges of your foreground subject
look rough, due to compression artifacts that appear as blocky edges around your
foreground subject. Don’t overdo this step, as it’s easy to lose details in the subject
you’re trying to preserve with this control.
Before adjusting the
Edge Thin slider
After moving the Edge
Thin slider to the right
Before adjusting the
Softening slider After moving the Softening
slider slightly to the right