Apple MA434Z/A User Manual - Page 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. Chapter 23 Color Correction 643