| Value | Meaning |
|---|---|
| UndefinedChannel | |
| RedChannel0x0001 | |
| GrayChannel0x0001 | |
| CyanChannel0x0001 | |
| GreenChannel0x0002 | |
| MagentaChannel0x0002 | |
| BlueChannel0x0004 | |
| YellowChannel0x0004 | |
| AlphaChannel0x0008 | Same as OpacityChannel |
| OpacityChannel0x0008 | |
| MatteChannel0x0008 | deprecated |
| BlackChannel0x0020 | |
| IndexChannel0x0020 | |
| CompositeChannels0x002F | |
| AllChannels0x7ffffff | |
| TrueAlphaChannel0x0040 | extract actual alpha channel from opacity |
| RGBChannels0x0080 | set alpha from grayscale mask in RGB |
| GrayChannels0x0080 | |
| SyncChannels0x0100 | channels should be modified equally |
| DefaultChannels((AllChannels | SyncChannels) & ~OpacityChannel) | Same as AllChannels, excluding OpacityChannel |
Specify an image channel. A channel is a color component of a pixel. In the RGB colorspace the channels are red, green, and blue. There may also be an alpha (transparency/opacity) channel. In the CMYK colorspace the channels area cyan, magenta, yellow, and black. In the HSL colorspace the channels are hue, saturation, and lightness. In the Gray colorspace the only channel is gray.