Apple Color 1.0 - Manual (Page 243)

Chapter 11 Color FX 243
In the following example, a Bleach Bypass node (which alters the saturation and
contrast of an image to simulate a chemical film process) is followed by a Curve node
(to further alter image contrast), which is followed by the Output node that must be
added to the end of all node trees.
Using Layering Nodes
A more sophisticated use of nodes is to use multi-input nodes to combine two or more
separately processed versions of the image for a combined effect.
In one of the simplest examples, you can tint an image by attaching a Color node
(which generates a user definable color) to one input of a Multiply layering node.