2019.x

Table Of Contents
The Channels Group
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Top, left to right: an original monochrome gradient image, the image in three-tone preview using default luma range
settings, and the image in three-tone preview with an expanded luma range.
Center, left to right: a video image, the image in three-tone preview using default luma range settings, and the image in
three-tone preview with an expanded luma range.
Bottom: the Luma Ranges graph used to create the expanded midtones range.
The Channels Group
The Channels group provides controls that let you redefine each output color channel (red, green,
blue) by blending different input color components in various proportions.
You can work with components from both the RGB (red, green, blue) and the YCbCr (luminance, red
chroma, blue chroma) color spaces. Because you can blend up to four input components to create
each output color channel, the Channels group offers very precise control over the final composition
of each color channel.
The Channels group also lets you preview the individual color channels in monochrome. This is
useful for checking the amount of contrast or noise in each channel.
The Channels group is particularly useful for identifying a color channel that is deficient in some way
— lacking in contrast, or noisy, for example — and repairing it by “borrowing” from another color
channel. For some kinds of images, this is the only way to improve the appearance significantly.
For example, you might preview the input channels for a segment and notice that, although the
master input shows acceptable overall contrast, the green channel is clipped to white and has
therefore lost contrast in the highlight range. You cannot “unclip” these green highlights by working
in the existing green channel because the brightness value of all the pixels in the highlight range is
the same (or very nearly so). The best solution to this problem is to blend a percentage of one of the
other channels into the green channel to reintroduce some contrast and detail. You might redefine the
green channel as 80% green and 20% red to solve the problem.