Apple Shake 4 - Manual (Page 643)

Chapter 23 Color Correction 643
rGamma
The red gamma value.
gGamma
The green gamma value.
bGamma
The blue gamma value.
aGamma
The alpha gamma value.
Invert
The Invert node inverts the color curve, so white becomes black and black becomes
white. A predominantly yellow image becomes predominantly blue if the red, green,
and blue (RGB) channels are selected in the channels field.
Invert also works on the Z channel, but assumes the Z is normalized, for example,
between 0 and 1. If this is not the case, you have an unpredictable result. If you need to
invert a non-normalized Z channel, use ColorX with a formula similar to the following in
the Z channel:
MaxZRange-z
Parameters
This node displays the following control in the Parameters tab:
channels
The channels you want to invert. You can use r, g, b, a, and/or z. To use multiple
channels, list them out. For example, rgz inverts the red, green, and Z channels.
Monochrome
The Monochrome node turns any image black and white. Unlike the Saturate node, you
can adjust the relative brightness that each channel contributes to the final BW image.
The default values are weighed according to the human eye’s different sensitivities to
red, green, and blue, but you can override these weights to simulate other effects, such
as how various black and white film stocks expose an image.
This node reduces a three-channel image (RGB) to a one-channel image (BW), and a
four-channel image (RGBA) to a two-channel image (BWA). If the three color channels
are identical, it is more efficient to use a Reorder with a value of “rrr,” since only the red
channel is read in. Monochrome reads all three channels in, and therefore has more I/O
activity.