Bodyshop: The Photoshop Retouching Guide for the Face and Body

Basic Overview: Channels

The channels contain information about color and brightness of a picture. Additional channels can be created from saved selections or help us create them. Large color spaces such as LAB and RGB cannot be rendered completely in the smaller print color space CMYK. That is also the reason why you will not see any difference between the colored pictures on the right.

A picture and its channels

A black and white picture contains one gray channel.

An RGB picture contains the fundamental colors red, green and blue. When mixed together, they make yellow, magenta and cyan. All pictures on the book DVD are in RGB.

A CMYK image consists of the fundamental colors cyan, magenta, yellow and black. When mixed together, they make red, green and blue. We need this color space in some chapters to create selections.

A LAB image consists of the lightness channel, the a-channel, which is responsible for red-green, and the b-channel, which is responsible for blue-yellow. We need this color space, for example, to sharpen an image without color shifts.

The Channels panel

Load color channels as selection

The corresponding brightness values of the color are loaded as selection if you hold the

Save and load selection

You can save an existing selection by clicking on the Save Selection as Channel ...