Layer Mask Created From Selection Doesn’t Remove Visible Layers Below

I am trying to create a paper cutout effect in Photoshop. I use the polygon lasso tool and and click the layer mask button and nothing happens at all. It creates a mask but does not "remove" all the layers underneath it making it impossible to use? 

If you apply a Layer Mask to a Layer it naturally applies to that one Layer. 

If you want a Layer Mask to affect multiple Layers you can put them into one Group and apply the Layer Mask to the Group. 

Please post the requested screenshots (including all pertinent Panels). 

I'm trying to think how you might make things clearer for yourself.

If you have the screen space, then setting the layer thumbnails to their largest size, then that gives you a better indication of what is masked and what isn't.

Also, turn off Layer Mask badges at the bottom of Panel Options.  I have forgotten why they were added now, but there was a lot of dissent when they were first introduced.  I think they might be to differentiate between raster and vector masks.

So, the saying goes Black Conceals, White Reveals.

The red layer has a central white retangle 'revealing' that layers red, but allowing the green layer to show outside.

Although the Green layer has a mask, it is doing nothing because the Red and Green layers are covering that area.

I've never heard of layer masks not working how they should before, but if you think you do have an issue, then a full resolution screenshot of your entire workspace, showing document window and layers panel, will help.

Hey @kay_2580, 

I modified the headline of your post to make it easier for others to find, and I also wanted to confirm—are you trying to create a mask and not a new layer?

If so, make sure you have the appropriate layer selected, then click on the mask icon. That should create a layer mask based on your selection.

Let me know if that helps or if you're seeing something different!

Could you post a screenshot of the Layers panel?