Apple Shake 4 Tutorials User Manual
Page 185
Chapter 6
Using Primatte
185
The alpha channel reveals the basic key. The majority of the background should appear
black in the alpha channel.
Note: If most of the background is medium gray, the center control was not selected
when you scrubbed for the bluescreen color. Make sure the center control is active,
then scrub the bluescreen again.
Output, one of the first parameters in Primatte, determines what is passed out of the
node. The output is set to “alpha only” by default.
Primatte contains the following output parameters:
•
alpha only: Only the alpha channel is modified; no spill suppression is performed.
•
on Black: Foreground is composited over black and spill suppression is performed.
•
comp: Foreground is composited over the background image with spill suppression.
•
status: Displays Primatte’s pixel analysis, allowing you to see how pixels are being
processed under the parameter settings. In this reference mode, pixels are displayed
in four categories or zones, represented by the following (arbritrary) colors:
•
Black represents pure background.
•
Red represents pure foreground.
•
Blue represents transparent areas.
•
Green represents transparent areas for spill suppression.
For more information about status color zones, see “
below.
To set the output mode to view the composite:
m
In the Primatte output parameters, enable “comp.”