Apply selection to layer mask

[DaBrownCO]

I’d like to know how to apply a luminosity mask to an existing mask. Along the same lines, how can I apply a selection to an existing layer mask? Thank you. 

[Chuck Uebele · Accepted solution]

It depends on how you want the luminosity mask or the selection to interact with the existing mask. You can make a selection out of an existing suminosity mask by ctrl/cmd clicking on the mask. Then you can select the mask you want to add the selection to and then filling the selection with either white or black, depending on if you want the selection to show or hide.

[DaBrownCO]

Hi Chuck,

I was thinking that might be the way to do this, but I wasn't sure if when you filled with white or black that the amount of fill would be adjusted accordingly to the tones in the luminosity mask. Maybe I over thought it.

Thanks!

David

[George_F]

I wonder if using Alt + Backspace for fill selection with foreground color is the solution you are looking for?  I use it often.

From there, you should be able to output a luminosity mask as a selection and then fill the selection using the above method.

[D Fosse]

And if you want to do it in a "non-destructive" (reversible) way - put the current layer with the existing mask in a Group, ctrl+G, and put a new mask on the group.

Or ditto smart object, but Group is usually simpler.