Apple Shake 4 - Manual (Page 532)

532 Chapter 19 Using Masks
For more information on transforming with onscreen controls, see Chapter 26,
“
Transformations, Motion Blur, and AutoAlign ,” on page 763.
8 To invert the mask, open the Mask subtree in the Brightness node, and enable
invertMask.
The mask is inverted, and the masked portion of the image is lightened.
Don’t Use Mask Inputs With Layer Nodes
Mask inputs are useful for color corrections and transforms. However, masks should
not be used for layer nodes. The logic is the complete opposite of what you think it
should be. Honest. As the following example shows, even with color and transform
nodes, masks should be used with caution.