Image files store color information in channels, or planes, of colors. You can separate an image into RGB, HSL, or CMYK color channels. An RGB image has three channels: red, green, and blue. An HSL image has three channels: hue, saturation, and lightness. Although you cannot create or edit an image using the CMYK model, you can still split the image into four channels: cyan, magenta, yellow, and black.

You can create a new grayscale image for each color channel; the original image is not affected. For example, an HSL image is split into separate grayscale images named “Hue,” “Saturation,” and “Lightness.” Each grayscale image represents the percentage and location of a color (such as red) or a characteristic (such as lightness) within the image.

You can edit the grayscale images and use them to create interesting effects or masks. You can then combine them again. If you split an image into CMYK channels, you can then send the four grayscale images to a printing service. You can also print CMYK separations directly.

You can split images into RGB, HSL, or CMYK color channels regardless of the type of color model (RGB or HSL) you choose as a display preference.

Color channels give you increased image-editing options. You can create a color shift by splitting an image into HSL channels, modifying the Hue channel, then combining the channels. You can also use a channel grayscale to create a selection.