I have two layers and an alpha channel:

enter image description here

And I would like to select an area on the "Layer 1" with a contour from the alpha channel, namely I want the "red" area be inside the selection. Is there any way to do this?

1 Answer 1


To load an Alpha Channel as a Selection....

Hold the Command/Ctrl key down and click the thumbnail for the Alpha Channel in the Channels Panel to load the Alpha Channel as a selection

Or.... Choose Select > Load Selection and pick the Alpha channel from the second dropdown list:

enter image description here

With the above in mind as to how to load a selection from an alpha channel....

For all selection methods... the Shift key will add to a selection, or the Option/Alt key will subtract from a selection.

So.. if a a selection for layer 1 is active....

  • to add the alpha channel (the red) to the active selection, hold down Command/Ctrl+Shift keys and click the Alpha Channel thumbnail in the Channels Panel.

  • to subtract the alpha channel (the red) from the active selection, hold down Command/Ctrl+Option/Alt keys and click the Alpha Channel thumbnail in the Channels Panel.

I, personally would merely use a layer mask....

  • Load the Alpha channel as a selection.
  • Highlight Layer 1 in the Layers Panel.
  • Click the Layer Mask button on the bottom of the Layers Panel to add a layer mask to Layer 1.

You can then select, paint, filter - whatever - on the mask which can often be easier than figuring out the right key combos, inverse for a channel, and procedural steps in order to get a selection of exactly what you need.

If you don't want a full Layer Mask, you can utilize the Quick Mask Mode -- load the Alpha Channel as a Selection, then tap the Q key on the keyboard, there's then a Quick Mask (by default you'll see red everywhere that is not part of the selection - red means "hide" in Quick mask). Just paint - black for hide, white for show. You can make selections, run filters, etc all in quick mask mode as well.When you're done, just tap Q again and you'll have a selection.

Truth is, there are numerous ways to create then add to or subtract from a selection. Which one works best in any given situation will vary.

  • Thanks a lot! I just needed to get a selection on the "Layer 1" to work with it. Aug 25, 2023 at 17:06
  • Ahh, then I may have gone overboard in explaining :) oh well, more info never hurt anyone.
    – Scott
    Aug 25, 2023 at 17:17
  • Completely agreed with you! Aug 25, 2023 at 17:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.