A depth channel (also called a Z-channel) is an extra channel of depth information that is integrated with a color image. Similar to an alpha channel it is an extra channel that provides data in addition to the color information included in the RGB channels. This depth map information helps artists to add a sense of three-dimensional space to their work.
By assigning a different level of depth to each pixel, artists can create the illusion of distance and depth in their images. The depth channel can also be used to control how light and shadow fall across an image, giving it a greater sense of realism. In addition, the depth channel can be used to generate special effects such as fog or haze. By utilizing the depth channel, artists can create dazzling visual effects that would otherwise be impossible to achieve.