Apple Shake 4 - Manual (Page 467)

Chapter 16 Compositing With Layer Nodes 467
Parameters
This node displays the following controls in the Parameters tab:
clipMode
Toggles between the foreground (0) or the background (1) image to set the output
resolution.
preMultiply
When this parameter is on (1), the foreground image is multiplied by its alpha mask. If
it is off (0), the foreground image is assumed to already be premultiplied.
addMattes
When enabled (1), the mattes are added together for the composite.
Screen
The Screen node mimics the effect of exposing two film negatives together. Technically,
it inverts both layers, multiplies the two layers together, and inverts the result. It is
particularly handy for reflections and luminescent elements, as it preserves the
highlights.
Parameters
This node displays the following controls in the Parameters tab:
clipMode
Toggles between the foreground (0) or the background (1) image to set the output
resolution.
SwitchMatte
The SwitchMatte node is a Copy command dedicated to copying a channel from the
second image into the matte channel of the first image. You can choose the source
channel, whether the channel is inverted, and whether the result is premultiplied.
Parameters
This node displays the following controls in the Parameters tab:
clipMode
Toggles between the foreground (0) or the background (1) image to set the output
resolution.
matteChannel
Tells Shake which channel to copy from the background to the foreground alpha
channel.