Converting between logarithmic and linear color – Apple Shake 4 User Manual
Page 441
Chapter 15
Image Processing Basics
441
Therefore, you are mathematically urged to color correct in linear color, or view a
conversion to linear using a VLUT while you adjust the color correction.
Converting Between Logarithmic and Linear Color
As previously mentioned, logarithmic images are simply a result of a color correction.
This correction has been standardized by Kodak. Every conversion function is
essentially the same. The Shake node that handles this correction is the LogLin node,
and is located in the Color Tool tab. Using this node, you can convert from log to linear
color, or linear to log color.
Typically, a LogLin node is applied after a FileIn node to convert the image from log to
linear color. You do your composite in linear color, convert back to log at the very end,
and attach the FileOut node. In the following node tree, LogLin1 has a conversion
setting of log to lin, and LogLin2 has lin to log.
This example also includes an imaginary 3D-rendered element, read in by the FileIn
node named LinearCGElement. These elements are almost always rendered in linear
color, so no conversion is necessary.