Color Range Effect; Difference Matte Effect (Pro Only); Extract Effect (Pro Only) - Adobe AFTER EFFECTS 7.0 Manual

ADOBE AFTER EFFECTS 7.0
464
User Guide
See also
"To key out a single color with the Color Key effect" on page 274

Color Range effect

The Color Range effect creates transparency by keying out a specified range of colors in either the Lab, YUV, or RGB
color space. You can use this key on screens that consist of more than one color or on bluescreens or greenscreens
that have been unevenly lit and contain different shades of the same color.
This effect works with 8-bpc color.
A poorly lit green screen (left) and a background layer (center) are combined using Color Range Key (right).
See also
"To use the Color Range effect" on page 275

Difference Matte effect (Pro only)

The Difference Matte effect creates transparency by comparing a source layer with a difference layer, and then keying
out pixels in the source layer that match both the position and color in the difference layer. Typically, it is used to key
out a static background behind a moving object, which is then placed on a different background. Often the difference
layer is simply a frame of background footage (before the moving object has entered the scene). For this reason, the
Difference Matte Key is best used for scenes that have been shot with a stationary camera.
This effect works with 8-bpc and 16-bpc color.
Original (left), Matte Only view of keyed-out subject (center), and composite of subject with new background (right)
See also
"To use the Difference Matte effect" on page 275

Extract effect (Pro only)

The Extract effect creates transparency by keying out (or extracting) a specified brightness range, based on a
histogram of a specified channel. It is best used to create transparency in an image shot against a black or white
background or against a background that is very dark or bright but consists of more than one color. You can also use
it to remove shadows from a composition.
This effect works with 8-bpc and 16-bpc color.