Apple Shake 4 - Manual (Page 989)

Chapter 32 The Cookbook 989
Color Macros
The following macros give you additional ways to manipulate color in your scripts.
AEPreMult Macro
This macro is intended to be used on an image that has a solid non-black background
color which is still considered “premultiplied.” By applying this function, you turn the
background color to black. This may not work with all images.
ColorGrade Macro
This macro allows you to pick three color levels from a source image (typically shadows,
midtones, and highlights) and match them to a target image. This is similar to
ColorMatch, except it does not have the special math to protect it from solarizing. As a
consequence, it is more accurate.