User Manual

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data specifically, do not affect alpha or auxiliary channels. This makes them convenient for
color-matching foreground and background layers you’re compositing, without worrying that
you’re altering the transparency or depth information accompanying that layer.
MediaIn, DeltaKeyer, Color Corrector, and Merge/MediaIn node.
TIP: If you’re doing something exotic and you actuallywantto operate on a channel
thats usually unaffected by a particular node, you can always use the Channel
Booleans node to reassign the channel. When doing this to a single image, it’s
important to connect that image to the background input of the Channel Booleans
node, so the alpha and auxiliary channels are properly handled.
Channel Limiting
Most nodes have a set of Red, Green, Blue, and Alpha buttons in the Settings panel of that
node’s controls in the Inspector. These buttons let you exclude any combination of these
channels from being affected by that node.
The channel limiting buttons in the Settings
panel of a Transform node, so only the Green
channel is affected.
For example, if you wanted to use the Transform node to affect only the green channel of an
image, you can turn off the Green, Blue, and Alpha buttons. As a result, the green channel is
processed by this operation, and the red, blue, and alpha channels are copied straight from the
node’s input to the node’s output, skipping that node’s processing to remain unaffected.
Transforming only the green color channel
of the image with a Transform effect.
Chapter – 69 Understanding Image Channels 1392