I have a bunch of solid, non-transparent logos, all of which contain drop shadows. The problem is the person who did them went WAY overboard in the size and darkness of the drop shadow.

I don't have access to the original PSD files, they're just flat PNGs. Given that, is there a way to modify the opacity of only those elements in an image that are already at least partially opaque? A way to select just those elements would also have the same result.

  • If the file is a flat PNG there are no separate layers you can modify. You'd have to make selections of the problem area and perhaps change the brightness/contrast. Depending on the complexity of the graphic, it could take some skill and time to fix it.
    – Billy Kerr
    Jul 29, 2019 at 22:35
  • @BillyKerr right. My hope was that there was some way to automatically create a selection, build a layer mask or something that would make this a slightly easier process.
    – Mordred
    Jul 29, 2019 at 22:53
  • Access to the origianl layered PSD file would be way to go if you want to make it easy. But you don't have that. For example if you had the original PSD, you could just select the drop shadow effect/layer, and reduce its opacity. When the file is flattened - all that data for the separate elements is lost.
    – Billy Kerr
    Jul 29, 2019 at 22:58
  • Without seeing the image, I don't know if there is a way you could automate the selection - it might not be possible depending on the complexity of the work.
    – Billy Kerr
    Jul 29, 2019 at 23:00
  • Maybe this would be helpful: graphicdesign.stackexchange.com/a/117198/2332
    – Joonas
    Jul 30, 2019 at 0:08

1 Answer 1


In Photoshop you can make a layer mask from transparency:

enter image description here

Now you can select the mask icon in the layers panel and apply curves to it:

enter image description here

This curve keeps fully opaque and fully transparent areas intact.

You can make the shadow smaller by painting black on it in the layer mask. As well you can select the shadow with the magic wand and delete it. Then you can make a new. Photoshop's layer style Drop Shadow is a way to do it fast.

You have different possibilities in GIMP, where transparency is as adjustable as RGB channels and you can combine selections which are made by using different criterias

The same example:

enter image description here

In GIMP it's possible to adjust transparency directly with the curves tool. One adjusts alpha channel instead of colors:

enter image description here

This curve keeps fully opaque and fully transparent intact.

As said, partially transparent areas can be selected and deleted to fully transparent. One possibility is to use the Fuzzy Selection tool (=the magic wand). Its tool options can be opened by double-clicking the tool icon. By setting parameter "Select by" = Alpha and turning the treshold (=capturing tolerance) low, say =5, one can select the opaque areas. Inverting the selection and pressing DEL kills those areas which aren't nearly opaque. Then it's the time to insert new drop shadow.

But if there happens to be faded edges of other colors than the black shadow? For ex. curved edges have partial transparency for antialiasing in all colors. Removing transparent parts removes also the anti-aliasing and makes the edges jaggy. That's fixable for other colors than the drop shadow color. One can for ex. select at first transparent enough areas. Then he makes selection intersection with those areas which have the color of the drop shadow.

  • This is exactly what I needed! No idea how I never noticed the "From Transparency" section in the Layer Mask menu. Adjusting the curves gave me exactly what I wanted. Thanks!
    – Mordred
    Jul 30, 2019 at 16:19

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