Apple Color 1.0 - Manual (Page 29)

Chapter 1 Color Correction Basics 29
An image’s contrast ratio is the difference between the darkest and brightest tonal
values within that image. Typically, a higher contrast ratio, where the difference
between the two is greater, is preferable to a lower one. Unless you’re specifically going
for a low-contrast look, higher contrast ratios generally provide a clearer, crisper image.
The following two images, with their accompanying histograms which show a graph of
the distribution of shadows, midtone, and highlights from left to right, illustrate this.
Furthermore, maximizing the contrast ratio of an image aids further color correction
operations by more evenly distributing that image’s color throughout the three tonal
zones that are adjusted with the three color balance controls in the Primary In,
Secondaries, and Primary Out rooms. This makes it easier to perform individual
corrections to the shadows, midtones, and highlights.
For more information about adjusting image contrast, see “ Using the Primary Contrast
Controls ” on page 166.