Apple Color 1.5 - Manual (Page 293)

As you fine-tune this effect, you want to adjust the amount the black-and-white image
contributes to the final effect by adjusting the Curve node, but you need to view the
output of the Multiply node in order to see how far to make the adjustment. In this case,
you double-click the Multiply node so that it becomes the viewed node (highlighted in
yellow).
Then, click the Curve node once to load its parameters into the Parameters tab. (The node
becomes highlighted in cyan.)
Bypassing Nodes
Each node has a Bypass button that appears at the top of its list of parameters. Click
Bypass to turn off the effect that node has on the tree without deleting the node from
the Node view.
293 Chapter 11 The Color FX Room