Digital images generally consist of the four standard channels: red, green, blue, and alpha. Nuke allows you to create or import additional channels as masks, lighting passes, and other types of image data.
A Nuke script can include up to 1023 uniquely named channels per compositing script. For example, you can combine multiple render passes from a 3D scene - an image from the red, green, and blue channels, a depth mask (z-depth channel), a shadow pass, a specular pass, lighting passes, and multiple mattes all stored within one image sequence in your composite.
NOTE: When a script is saved, any channels that are not referenced in the script are discarded automatically.
Here's a quick overview of the workflow:
| 1. | Channels in Nuke are always a part of a layer. You can create new channels and layers using the new option in the channel selection dropdown menus (such as output and mask) in a node’s properties panel. For more information, see Object Material Properties. |
| 2. | Using the channel selection controls you can select which channels the node is processing and outputting, or using as a mask when color correcting for instance. For more information, see Calling Channels and Selecting Masks. |
| 3. | The channels can also be linked to other channel controls through the Link menu. For more information, see Linking Channels Using the Link Menu. |
| 4. | Using the Shuffle and ShuffleCopy nodes, you can rearrange your input channels and apply the result in the output. For more information, see Swapping Channels . |