Copying a selection (or any channel/mask) across images

[ofnuts]

There are case where it is useful to transfer a selection/channel/mask across images (for selections, as a first step, . save you selection to a channel ("Select/Save to channel")).

• Direct cut-and-paste:
  • In source image:
    • open Channels list, and select the saved selection
    • "Edit/Select all" (or "Edit/Select none", both work)
    • "Edit/copy"
      
  • In target image:
    • Open Channels list, and create a new channel, ti should be selected (in blue)
    • "Edit/paste"
    • In Layers dialog: you see a "floating selection" with the copied channel (you should n't have a selected layer, since the selected drawable" is the channel you just created)
    • Right click and "Anchor layer": this anchors the floating selection it in the new channel
      
• Via file (so you can save a selection and reuse it later...)
  • In source image:
    • open Channels list, and select the saved selection
    • "File/Save as...", and save as PNG
    • You should get a warning that you are saing a channel and not a layer. Confirm.
      
  • In target image:
    • "File/Open as layers", and load your saved selection.
    • Make all layers invisible except the loaded selection
    • In channels dialog, duplicate any of the Red, Green or Blue channels (you can also directly use "Channel to selection")
    • Discard or hide the loaded layer, restore visibility of other layers
      

[henrybritt]

Nice Helpful tip. Great share. Thanks.