I would like to know if there is some kind of "shadow / object" that replicates "subtraction / differentiation" in all the layers except the background in photoshop. Adobe illustrator does something similar, but not to the level I'm looking for.

I present an example written with layers:

  1. Layer Letters
  2. Layer Drawings ("subtraction / differentiation") for all layers except background color
  3. Layer shapes
  4. ....

I put a visual example. enter image description here

I am looking to do this without a "Mask". Simply by putting a filter on the image (either a border or not) but making the image outline transparent so that the background can be seen, above the other layers. Imagine you have many images. If I have to make a mask for a lot of images... it might take too long. That's why I'm looking for an alternative.

  • Are you looking for knokouts. Yeah that can be done.
    – joojaa
    Mar 11, 2021 at 19:22
  • Any ideas to do this? or PS just can't do it
    – delive
    Jun 1, 2022 at 12:31

2 Answers 2


Not sure if this works for your specific situation...

However, you could merely add a Layer Style Stroke to the top layer, using a color to match any background color.

enter image description here

You do, of course, get the rounded corners from the stroke. Which I'm aware are not always desired. To get around those round corners...

The only other option I can think of is a mask to hide portions of underlying layers....

enter image description here

But you do need to create the shape on the mask. It won't be directly tied to any other shape/layer.

  • @delive The stroke issues you present is specifically why I posted the second option utilizing a mask.
    – Scott
    Mar 12, 2021 at 20:30
  • @delive Not sure I understand really... a mask should work.. as in this
    – Scott
    Mar 12, 2021 at 20:37
  • Well, ultimately I believe it's a matter of construction. I'm working with a flat jpg so I don't have constructed artwork with layers and must generate layers. But... well... here -- If you are working with shape/vector layers in Photoshop you can set the layer interaction options to get a "subtract" function between shape layers.
    – Scott
    Mar 12, 2021 at 20:51
  • "subtract" function between shape layers" It is not a solution.
    – delive
    Mar 12, 2021 at 21:13
  • Sorry.. I can think of several methods to create such artwork.. but nothing as dynamic as you are seeking. At a minimum if text were to change any knockout or mask would also need to be changed, which is simple enough, and could be easily done via an action, but not dynamically. It may not be possible. Note that I don't think this is dynamically possible in Illustrator either. Perhaps someone else will be familiar with a method I am not.
    – Scott
    Mar 12, 2021 at 21:29

There is a way to achieve what you want using knockout.

Your bottom layer must be a proper Background layer without transparency. So if it's not, use Layer > New > Background from Layer to turn it into one.

Place the layer you want to use to subtract above the layers you want to subtract from. It can be any kind of layer or group.

Enter the layer's Blending Options. Either double-click the layer (not the name of the layer) or select Blending Options from the Add a layer style button in the bottom of the Layers panel.

Set Fill Opacity to 0% and set Knockout to Shallow (limits the knockout to the group the layer is in) or Deep (makes the layer knockout all layers below it).

  • If you group layers then you can make the knockout only affect the layer gtoup stack.
    – joojaa
    Jun 3, 2022 at 9:03
  • @joojaa, yes with Knockout set to Shallow. I should perhaps make that clearer.
    – Wolff
    Jun 3, 2022 at 9:15

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