Apple Color 1.5 - Manual (Page 214)

• If Limit Shadow Adjustments is turned on: The black point is raised, but the white point
remains at 100 percent. This means that when you make any adjustments with the
Shadow contrast slider, all midtones in the image are scaled between the new black
point and 100 percent. Notice how the top of the slope in the Waveform Monitor stays
in place while the black point changes.
You'll probably leave the Limit Shadow Adjustments control turned on for most of your
projects, since this setting gives you the most control over image contrast (and color, as
you'll see later) in your programs.
214 Chapter 9 The Primary In Room