Keying - Nuke 101: Professional Compositing and Visual Effects - page 322

You can adjust the Clip Black property to remove any remaining gray pixels in
the background area. If you lose too much detail, you can use the Clip Rollback
property to bring back fine detail.
13. Adjust Clip Black and Clip Rollback to get rid of all the gray pixels in the back-
ground area. I ended up with 0.02 in the Clip Black property and 0 in Clip Roll-
back, which is the default value.
14. If you have any holes in the white foreground area that need filling you can use
the Clip White property to fill those in.
The View drop-down menu at the top of the Properties panel will change the out-
put of the Keylight node to show one of several options. The important ones to
note are:
• Source: Shows the source image as it came in.
• FinalResult: Showsapremultipliedforegroundimagewithitsmatte.This
is normally how you would output the result of this node.
• Composite: Creates a composite over whatever is in the Bg input of the
Keylight node. You will normally not use the Keylight node to composite
the foreground over the background, but it is convenient while keying to
see your final composite and see what other work is left to be done.
• Status: Shows a black, gray, and white representation of the keying pro-
cess, where white represents complete foreground pixels, black repres-
ents complete background pixels, and a 50% gray represents transparent
or spill suppressed pixels. This is a handy tool to see the status of your
matte and pinpoint problematic areas ( FIGURE 7.32 , next page).