Apple Shake 4 - Manual (Page 655)

Chapter 23 Color Correction 655
hExpr
Use this function to change the input value, always represented by “x.”
aExpr
Use this function to change the input value, always represented by “x.”
LookupHSV
The LookupHSV node performs exactly like Lookup, except that it works on the HSV
channels instead of RGB channels.
Note: You cannot clone LookupHSV nodes in the node tree using the Paste Linked
command.
Parameters
This node displays the following controls in the Parameters tab:
vExpr
Use this function to change the input value, always represented by “x.”
sExpr
Use this function to change the input value, always represented by “x.”
hExpr
Use this function to change the input value, always represented by “x.”
aExpr
Use this function to change the input value, always represented by “x.”