User guide
Chapter 7 Make image adjustments 303
Selectively adjust the color values in an image
You use the Color adjustment controls to selectively adjust the red, green, blue, cyan, magenta,
and yellow colors in an image. Each color has individual Hue, Saturation, and Luminance
controls. If you need to adjust the hue, saturation, and luminance of a color that doesn’t appear
in the Color controls, you can use the Color eyedropper to identify a hue in the image that
needs adjusting.
Although segmenting control of hue, saturation, and luminance on a per-color basis may seem
complicated at rst, restricting these adjustments to specic colors helps correct and enhance
targeted colors without aecting others. In addition, Aperture provides Range controls used to
set the extent of colors aected by the Hue, Saturation, and Luminance adjustments. The extent
of colors aected by these adjustments is also known as chromatic spread. You use the Range
controls to ne-tune your color adjustments.
You can also brush the Color adjustment on selected parts of an image. For more information,
see Apply brushed adjustments on page 228.
Before Color adjustment
After Color adjustment
(adjusted the hue and
saturation of blue)
Hue, saturation, and luminance describe the characteristics of a particular color:
•
Hue (H): Describes the actual color itself. Hue is measured as an angle on a color wheel. Moving
a Hue slider in Aperture remaps the color from its original position on the color wheel to the
new position indicated by the slider. Hue adjustments are often made to match the color
of the same subject in dierent images. Adjusting the hue of an image is particularly useful
when the subject you shot moved between various lighting conditions. Another advantage
of adjusting the hue of an image is that camera models of dierent types or from dierent
manufacturers rarely capture and render color exactly the same way. You can use the Hue
controls to match the color of a subject shot by two dierent cameras, so that when the
images are placed side by side, they match.
•
Saturation (S): Denes the intensity of a specic hue. A saturated hue gives the color a vivid
and pure appearance. A less saturated hue appears atter and more gray. A completely
desaturated hue becomes a shade of gray.
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