Black pixels in an alpha channel correspond to masked, or non- selected, pixels in an image. White pixels correspond to selected pix- els. Gray pixels correspond to various levels of selection, with lighter grays corresponding to greater selection than darker grays. Note: If you want black pixels to correspond to selected, rather than masked pixels, click Selected Area in the New Channel or Channel Options dialog box. Using the Channels palette The Channels palette displays the channels contained in a paint object when the paint object is in edit mode. The palette also displays the channels contained in any object that has a channel mask when you edit the mask. You can use the palette to create, duplicate, and delete channels; to change channel options; and to make selections by loading channels. To open the Channels palette:  Choose Image > Show Chan- nels. Composite channel Select the first channel in the palette to make all color channels visible and active. Paint objects in CMYK Color, RGB Color, and LAB Color modes have composite channels. The channel is labeled “CMYK” for a CMYK Color image, “RGB” for an RGB Color image, and “LAB” for a LAB Color image. Paint objects in Indexed, Grayscale, Black & White, and Duotone modes have single channels. A vector object that has a channel mask has an “object channel.” Color channels Color channels appear below the composite chan- nel in the Channels palette. Color channels store the color data in an image. The image mode determines the number of color channels. CMYK Color images have Cyan, Magenta, Yellow, and Black color channels. RGB Color images have Red, Green, and Blue color chan- nels. LAB Color images have “A” and “B” color channels and a Lightness channel. Multichannel images have numbered channels that contain grayscale pixels only. Alpha channels Alpha channels contain grayscale pixels which can represent a selection. You can use alpha channels to create chan- nel masks. Any paint object can have alpha channels. However, paint objects in Black & White mode must have a channel mask before they can contain alpha channels.
Canvas 8 Help: Selections and channels (20 of 32)                                                   Page #670