You can save pixel selections for later use in the current project or future projects. It's useful to be able to reinstate more complex selections at any time and stage of your project.
Any number of selections can be stored as spare alpha channels in the Channels panel for future use. From there you can reinstate any selection on demand.
Instead of using the Channels panel, selections can be saved to a standalone file. Saved selections can then be loaded from the file into the same or another project.
The selection is stored at the bottom of the Channels panel as a new 'Spare Channel' entry.
On the Channels panel, -click the 'Spare Channel' entry, which lets you:
The selection is stored at the bottom of the Channels panel as a new 'Spare Channel' entry.