Apple Shake 4 - Manual (Page 611)

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Color Correction
Shake’s color-correction and pixel-analyzer functions
provide many ways of analyzing and manipulating the
color values of your images.
Bit Depth, Color Space, and Color Correction
By default, Shake works with a color range of 0 to 1 in RGB linear space. Shake allows
you to work at different bit depths, so 0 is considered black and 1 is considered white.
Ordinarily, values above 1 and below 0 are clamped (constrained to a value between 1
and 0) as they’re passed from node to node down the tree of image-processing
functions. This can have a profound effect on the resulting image processing in your
script, with the following caveats:
• Nodes that concatenate are not subject to this clamping.
• Clamping does not occur when you work in float bit depth, because 32-bit (float)
computations preserve values above 1 and below 0.
Working in Different Color Spaces
When working with logarithmic Cineon plates, apply a LogLin node to avoid
unpredictable results. The LogLin node allows you to jump from logarithmic to linear
space, or linear to logarithmic space. For more information, see “
The Logarithmic
Cineon File ” on page 437.
To apply an effect such as a Blur node in a different color space (for example, to blur
the color difference channels in a YUV image, but not the luminance), apply a
ColorSpace node to the image to convert it to the different color space. Then, add the
effect node—in this example, the Blur node. To return to your original color space, add
another ColorSpace node.