Apple Final Cut Pro 7 - Manual (Page 1302)

Blacks, Midtones, and Whites
In the Final Cut Pro color correction filters, most of the controls that you use to correct
your clips are divided into controls over blacks, midtones, and whites. These represent
different overlapping ranges of luma values in your image.
Blacks
Blacks make up the minimum range of luma in your clip. If you looked on a smooth
gradient from black to white, controls that affect the blacks will affect your picture in the
leftmost three-fourths of the gradient, from black to gray. The effect that controls have
over the blacks of an image starts to diminish at approximately 75 percent luma, shown
above. This excludes the brightest parts of your image.
Midtones
Midtones make up most of the gray tones of an image. On the same gradient, controls
that affect the midtones will affect the middle half of the gradient, excluding the deeply
white and black parts. The effect that controls have over the midtones of an image starts
to diminish at 25 and 75 percent luma, shown above. This excludes both the brightest
and darkest parts of your image.
Whites
Whites make up the maximum range of luma in your clip. On this gradient, controls that
affect the whites affect the rightmost half of the gradient, from gray to white. The effect
that controls have over the whites of an image starts to diminish at approximately 25
percent luma, shown above. This excludes the darkest parts of your image.
When you use controls that affect only one of these ranges, all changes made to the hue,
saturation, and luma levels of your picture happen exclusively in the area that falls within
that particular range of luma. This allows you to perform very targeted color correction
only where it’s needed, such as subtly manipulating the hue of the highlights without
touching the shadows, or vice versa.
1302 Chapter 78 Measuring and Setting Video Levels