Apple Shake 4 Tutorials - Manual (Page 189)

Chapter 6 Using Primatte 189
When scrubbing fails, it may be time to apply some rotoscoping to the key. In this case,
a holdout matte will work better to mask problem areas such as the dark portion under
the woman’s arm. This technique is covered in the “Masking Primatte” section below.
If you tried to remove the dark area with a foreground operator and failed miserably,
delete the operator.
To delete an operator:
m In the Primatte1 Parameters tab, click the delete op button, below the currentOp
parameter.
Note that the background of the key, especially on the left side, needs work.
To modify the background of the key:
m In the Primatte1 Parameters tab, click the background operator button, the scrub the
left side of the image.