Apple Motion 3 - Manual (Page 926)

926 Chapter 10 Using Filters
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 greenscreen, 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 greenscreens 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 bluescreen 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 greenscreen, 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. Values range from 0 to1.
Mix: Sets what percentage of the original image is blended with the filtered image.
Values range from 0 to 100%.