Apple Color 1.5 - Manual (Page 296)

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.
This adjustment multiplies the color with the corrected image. (Remember, disconnected
inputs always link to the corrected image data.) Because of the way image multiplication
works, the lightest areas of the image are tinted, while progressively darker areas are less
tinted, and the black areas stay black.
In a slightly more complicated example, the image is processed using three nodes: a
Duotone node (which desaturates the image and remaps black and white to two
customizable colors), a Curve node (to darken the midtones), and a Blur node. The result
is connected to one input of an Add node (with both Bias parameters set to 1).
296 Chapter 11 The Color FX Room