Apple Shake 4 Tutorials - Manual (Page 36)

36 Chapter 1 Shake Basics
In the illustration below, the radius is set to 312 and the falloffRadius is set to 370.
It’s looking better, but there’s still a big difference between the sharp area and the
blurred area. Adjust the gradient colors to fix this, then set the Blur1 node to use a color
channel from RGrad1 as the mask, instead of the alpha channel. When you change the
gradient colors and substitute the alpha channel with one of the color channels, you
can adjust the opacity of the mask and its effect on the blur filter.
7 Click the right side of the Blur1 node to load its parameters, expand the Mask subtree,
then set maskChannel to R (red).
It doesn’t matter which of the three color channels you specify. You just need to choose
one of the color channels to use as the mask.
8 Now click the right side of the RGrad1 node to load it back into the Parameters tab.
9 Click the centerColor control.
The Color Picker opens.