How to use a channel as mask in Photoshop?

Question

Is there a way in Photoshop to use a channel (for example red or Lab luminosity) as a mask for a layer?

Asked by Paolo

Answer

Yes, two ways I know of:

• Go to the channels palette.

• Select the channel you want.

  

• Ctrl-click (Cmd-Click on a Mac), to copy the channel.

• Then go back to your layer and add your mask

  

or

• create a blank, white mask on your layer
• make sure the mask is selected

• go to Image > Apply Image

  

• select the channel you want from the channel dropdown

• click ok

I use a red mask when doing skin softening, because skin will show up light in the red channel. I describe this in my answer to this question: What is the best techinque to smooth skin?

Answered by MikeW

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