Apple Color 1.5 - Manual (Page 242)

What Is Color Contrast?
Contrast in this documentation usually describes the differences between light and dark
tones in the image. There is another way to describe contrast, however, and that is the
contrast between different colors in an image. Color contrast is a complex topic, touching
upon hue, color temperature, lightness, and saturation. To greatly simplify this diverse
topic, color contrast can pragmatically refer to the difference in color that exists in
different regions of the image.
In the following example, the image starts out with an indiscriminate color cast; in other
words, there is red in the shadows, red in the midtones, and red in the highlights, so
there aren’t many clearly contrasting colors in different areas of the image. By removing
this color cast from some parts of the image, and leaving it in others, you can enhance
the color contrast between the main subject and the background. In images for which
this is appropriate, color contrast can add depth and visual sophistication to an otherwise
flat image.
Correcting a Color Cast Using Curves
In the following example, you'll see how to make a targeted correction to eliminate a
color cast from the lower midtones, shadows, and extreme highlights of an image, while
actually strengthening the same color cast in the lower highlights.
The following image has a distinct red color cast from the shadows through the highlights,
as you can see by the elevated red waveform in the Parade scope.
Note: For clarity, Broadcast Safe has been turned off so you can better see the bottoms
of the waveforms in the Parade scope.
In this particular shot, you want to keep the red fill light on the woman's face, as it was
intentionally part of the look of the scene. However, to deepen the shadows of the scene
and make the subject stand out a little more from the background, you'd like to remove
some of the red from the shadows.
242 Chapter 9 The Primary In Room