Apple Color 1.5 - Manual (Page 217)

No matter what contrast ratio you decide to employ for a given shot, the Midtone slider
is one of your main tools for adjusting overall image lightness when creating mood,
adjusting the perceived time of day, and even when simply ensuring that the audience
can see the subjects clearly.
Note: Even though midtones adjustments leave the black and white points at 0 and 100
percent respectively, extreme midtones adjustments will still crush the blacks and flatten
the whites, eliminating detail in exchange for high-contrast looks.
Adjusting the White Point with the Highlight Slider
The Highlight slider is the inverse of the Shadow slider. Using this control, you can raise
or lower the white point of the image, while leaving the black point relatively untouched.
All the midtones of the image are scaled between your new white point and 0 percent.
If the image is too dark and the highlights seem lackluster, you can raise the Highlight
slider to brighten the highlights, while leaving the shadows at their current levels. Notice
that the black point of the gradient's slope in the Waveform Monitor remains at 0 percent
after the adjustment.
Note: In this example, Broadcast Safe has been turned off, and you can see the white
level of the gradient clipping at the maximum of 109 percent.
217 Chapter 9 The Primary In Room