Apple Color 1.0 - Manual (Page 216)

216 Chapter 10 Secondaries
Each qualifier has three sets of handles, which correspond to three knobs on
compatible control surfaces. These handles can also be manipulated directly onscreen
using the mouse. They are:
 Center: A single handle defines the middle of the selected range of values.
 Range: An inner pair of handles to the left and right of the center handle define the
initial range of values that contribute to the keyed matte. These are the solid white
pixels seen in the matte.
 Tolerance: An outer pair of handles define a range of values that surround the range
values to create falloff, giving a soft edge to the keyed matte. These are the lighter
gray pixels seen in the matte.
To adjust the center point for any qualifier:
m Drag anywhere within the center of the two range handles.
Range
Center
Tolerance