Copying the channel

[gimp-artist]

I saved a selection to a channel to use it later. I want to save the channel with another xcf files as well. How do I copy the channel to other projects?

[rich2005]

Depends what you want to do and on aspects such as image sizes and the channel itself.

A channel will copy with ctrl-c. But to get it into a new channel. Make one, fill with white, edit -> paste.

Probably a more usual way is keep the channel with the original image as an xcf.
example https://i.imgur.com/53WoWXB.jpg

Then you can open the destination image Open As layers (but not the other way round)

Probably (certainty) there will be a mismatch in canvas size. Correct that. https://i.imgur.com/2BdxSvN.jpg (edit:correct shot)

Now put the channel to a selection for editing. https://i.imgur.com/N5hFwYY.jpg but you will find 99% of the time you need to do a bit of work with the selection for a fit.

Same procedure but send the channel to a layer mask: https://i.imgur.com/TmFba6T.jpg

----
Those examples were from luminosity masks, but if it is a simple selection, clean edges, no partial transparencies, instead of creating a channel consider selection -> to path. Then export the path to a svg file for later use.

[Ofnuts]

Method #1:

• Drag the channel thumbnail from the source image's Channels list to the target image. This adds it as a layer in the target.
  
• Open the Channels list in the target image, and drag any of the R,G, or B channels to the main list to copy it
  
• Delete the copied layer
  

Method #2:

• Make the channel active in the source image
  
• Select>All, Edit>Copy or Ctrl-C
  
• In the target image, create a new channel, and make sure it is the active channel
  
• Edit>Paste, and don't worry that it seems to be pasted as a layer, this isn't really the case
  
• Layer>Anchor (or Ctrl-H) and it gets pasted/anchored into the target channel
  

Also, little known trick: if the active layer is a channel, File>Export doesn't export the image (ie, composition of the layers) but the channel. But to load a channel from file, you have to open the file as layers, and drag an RGB channel as in method 1#.