Color ranges and color channels are not the same thing. A color range
is a series of one or more colors that are contiguously located on the color
wheel, as shown in Figure 1. Cyan is a color range. Yellow-green is
another color range.
A color channel, as described in the
Channels and Bit Depth page, contains the information that defines the color
and tonal information for just one of the colors in a color model. As seen
in Figure 2, the RGB color model has three color channels; one for red, one for
green and one for blue. The red information is stored in the red channel.
The green information is stored in the green channel. And the blue
information is stored in the blue channel. All three channels blended
together create the color image. In the Adobe Photoshop Channels panel,
channels are represented as black and white masks.
When working with color channels, we are working with any pixel that has
information in that channel. When working with color ranges, we are
working only with those pixels whose dominant color is in the selected range.
Figure 1. Color Ranges as shown in a Color Wheel
Figure 2. Color Channels