and edit channels. To display the Channels palette, choose Image > Show Channels. Vector objects and text objects do not have color or image channels. However, you can create a channel mask for any object. If an object has a channel mask, you can place the channel mask in edit mode, and use the Channels palette to work with the channel mask and cre- ate alpha channels. Alpha channels are stored with an object as long as the object has a channel mask. Color channels Images in RGB Color, CMYK Color, and LAB Color mode have separate color channels. A color channel stores one component of the image. For example, in CMYK Color mode, the Magenta channel stores the magenta parts of the image. This channel contains the image that would appear on the magenta plate if you output color separations. A paint object’s image mode determines the number of color chan- nels. RGB Color images have Red, Green, and Blue color channels. CMYK Color images have Cyan, Magenta, Yellow, and Black chan- nels. LAB Color images have Lightness, A, and B channels. In the Channels palette, a composite channel appears above the color channels. The composite channel represents the complete image — the composite of the image’s color channels. The composite channel is labeled RGB, CMYK, or LAB, depending on the image mode. Other image modes do not have separate color channels. Images in Black & White, Duotone, Indexed, and Grayscale mode have a single image channel. Alpha channels Alpha channels are channels you can use to store and edit selections in any image. Because alpha channels are used for image selections, they are also referred to as “selection masks.” After you make a selection in an image, you can save the selection in an alpha channel. Later, you can load the channel to make the same selection. An alpha channel is a grayscale channel that is the same size and res- olution as the paint object in which it is stored. Pixels in alpha chan- nels can range in lightness from 0 (black) to 255 (white). The lightness levels of pixels in an alpha channel correspond to a range of selection levels.
Canvas 8 Help: Selections and channels (19 of 32)                                                   Page #669