You open an image in Photoshop, go to Image > Adjustments > levels, and then select the eyedropper to set the blacks.

When you hover over the image with the eyedropper and press the alt key, what does this operation do?
How do I apply that action on my image so I can export it?

That's on Windows. I don't know if it has the same effect on a Mac.


2 Answers 2


The effect looks like posterization - it's an ultra high contrast effect, so you can easily see the location of the shadow/highlight pixels when holding down Alt when the shadow or highlight picker tools are selected. This has nothing to do with Windows/Mac versions. Photoshop works the same on both platforms.

You could create a similar effect as follows:

  1. Add a Posterize adjustment layer, and set the levels to 2.

  2. Under that, add an Exposure adjustment layer.

  3. You can then adjust the effect by changing the exposure slider.


enter image description here

  • Great, thanks so much for your detailed explanation
    – Aenaon
    Commented Aug 5, 2021 at 8:15

When you hold the alt/ option key while adjusting the black point (or the white point) with the eyedropper on a levels adjustment, Photoshop is showing you either the "blown" highlights or the "lost" (too black) shadow areas.

This is so that you can make adjustments and know you aren't losing too much detail in the whites or blacks. That is the purpose of the Alt/ option key while making this kind of adjustment.

As far as being able to export this look the answer by @BillyKerr is a very good solution.

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