Apple Motion 4 - Manual (Page 1026)

The Primatte RT filter makes a guess as to the non-subject color you are trying to remove.
It makes a guess based on the dominant color present in the image, which may or may
not be the color of the background. For example, if the image is a large red object that
obscures most of a green screen, Primatte RT selects Red as its base sample. In this case,
however, Primatte RT correctly guesses that you’re trying to key out the blue color. If
Primatte RT’s guess is incorrect, use the Auto Sample buttons to choose a different color.
Tweaking the Noise Removal parameter can help for blue or green screens that have
some variance in their color value. Additionally, the darker areas of your object can fool
the keyer’s defaults, so in order to get a clean matte you may have to adjust Matte Density
so the background doesn’t show through these dark areas. Lastly, Spill Suppression can
be used to reduce blue screen reflections or interactions with the foreground object.
5 Turn on the background layer.
Spill Suppressor
Whenever you key an image that was shot against a blue or green screen, there’s a good
chance that some color reflected off of the screen and illuminated the edge of the
foreground subject. This fringing around the edge of the subject is called spill, and is
usually difficult to eliminate because it’s actually part of the subject you’re trying to
preserve. The Spill Suppressor filter deals with this by tinting the keyed color in order to
turn it into a neutral tone.
Note: The Spill Suppressor may inadvertently tint other areas of the foreground subject
in addition to the colored fringe, so adjust its settings with care.
Parameters in the Inspector
Spill Type: Sets the type of spill to be suppressed. Select Blue or Green.
Amount: Sets the amount of spill to be suppressed.
Mix: Sets what percentage of the original image is blended with the spill-suppressed
image.
HUD Controls
The HUD contains the following controls: Spill Type and Amount.
1026 Chapter 16 Using Filters