Apple Final Cut Pro 6 - Manual (Page 1032)

Chapter 13 Installing and Managing Video Effects 247
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Difference Matte Compares two clips and keys out areas that are similar. A View
pop-up menu allows you to look at the source of the clip (with no
key applied), the matte created by the filter, the final matted image,
or a special composite of the source, matte, and final image for
reference. The Difference Layer clip well allows you to specify
another clip to compare the current image to for keying. Threshold
and Tolerance sliders let you adjust the key to try to isolate the
parts of your image that you want to keep.
Luma Key Similar to a chroma (color) key, except that a luma key creates a
matte based on the brightest or darkest areas of an image. Keying
out a luma value works best when your clip has a large discrepancy
in exposure between the bright or dark areas in the frame that you
want to key out, and the foreground images you want to preserve.
A View pop-up menu allows you to look at the source of the clip
(with no key applied), the matte created by the filter, the final
matted image, or a special composite of the source, matte, and
final image for reference. A Key Mode pop-up menu allows you to
specify whether this filter keys out brighter, darker, similar, or
dissimilar areas of the image. A Matte pop-up menu lets you create
either alpha channel information for that clip or a high-contrast
matte image applied to the color channels of your clip, based on
the matte created by this filter.
Spill Suppressor - Blue When you use the blue and green screen key to key out the blue in a
clip, sometimes there is residual blue fringing, referred to as spill,
around the edge of the foreground image. This filter removes this
blue fringing by desaturating the edges where the fringing appears.
This filter should always appear after a color key in the filter list
shown in the Filters tab of the Viewer. It may have a slight effect on
the color balance of your image.
Spill Suppressor - Green Works in the same way as the Spill Suppressor - Blue filter, but on
green fringing.
1 Works in 32-bit floating point if your sequence is set for high-precision rendering in the Video Processing tab of the
Sequence Settings window.
Filter Result