Apple Shake 4 - Manual (Page 444)

444 Chapter 15 Image Processing Basics
Logarithmic Color and Float Bit Depth
Here is where it gets tricky. If you examine the following logarithmic-to-linear
conversion curve, you can see that clipping occurs above 685.
The LogLin node does have a roll-off operator, which helps alleviate the sharp corner at
the 685 point, but this is inherently a compromise—you are throwing data away. You
do not really see this data disposal in linear color. However, once you convert back to
logarithmic, the color clipping is evident.
In the following grayscale examples, the left image is a ramp with an applied log to lin
conversion. It is now in linear color. The right image is the left image converted back
into log color representation. Quite a bit of clipping has occurred.
Log grayscale
converted to linear color Previous example
converted back to log color