In Photoshop, a channel is a grayscale image that stores different types of information: Color information channels are created automatically when you open a new image. The image’s color mode determines the number of color channels created. For example, an RGB image has a channel for each color (red, green, and blue) plus a composite channel used for editing the image. An image can have up to 56 channels. All new channels have the same dimensions and number of pixels as the original image. (See illustration under alpha channel.)