I have a fairly large pdf file that is a scan and it has a background shadow from a poor scanning job.

I want to remove the shadow and found online tools such as screenwritr and pdffiller but they cant upload my file since it is too big.

Are there any PDF applications in windows for desktop that can remove shadows ?

I tried Adobe Pro and it told me my document didnt have a background to remove under the accessibility options.

How can I get rid of the shadow in this pdf document from the poor scanning job ?


2 Answers 2


If it's a scan, it's a raster image. Your best bet is to use a raster image editor such as Photoshop (not free) or GIMP (free and open source). It would have been helpful if you could have shown an example of the problem image, since a fix will depend on how bad the the problem is.

But generally, it is possible to do a levels adjustment in raster software.

An example

Here's a page with excessive background shadow, some of the letters from the back of the printed page are visible. Here I'm doing a levels adjustment to remove the shadows, by dragging moving the sliders in the levels histogram.

enter image description here

This was done in GIMP but the same is possible in Photoshop.

  • Okay I opened my pdf as layers in GIMP and there are 100 pages. Do I had to edit each page or "layer" in GIMP individually or can I do a mass change to all layers all at once ? I don't even know how to switch between different layers in GIMP, it keeps showing me the last page only when I open 100 pages ! How do I switch between layers and edit say page 2 or 3 or 4 ?
    – user4434
    Jan 22, 2023 at 7:17
  • meant have to..
    – user4434
    Jan 22, 2023 at 7:36
  • Yeah GIMP can only edit one layer at a time. The layers are in the layers panel. Hide those layers you are not working on by using the eye icion, so you can see the layer underneath. Start at the top and work your way down. see screen capture here
    – Billy Kerr
    Jan 22, 2023 at 10:40
  • It's possible to use scripts with GIMP for editing multiple layers at once, but you'd need to find one or write one. This functionality isn't in the standard toolset. Photoshop has action recording, which might be another approach, but Photoshop isn't free.
    – Billy Kerr
    Jan 22, 2023 at 10:43
  • Also note that trying to fix all the pages in one go might not be ideal anyway. If each page is even slightly different, each may require its own specific levels tweak.
    – Billy Kerr
    Jan 22, 2023 at 10:55

Great example from Billy Kerr of levels slider in GIMP. As he mentioned, in Photoshop check out image-adjustments-levels for a similar interface to take care of that scanned shadow.

  • I already mentioned the same can be done in Photoshop.
    – Billy Kerr
    Jan 22, 2023 at 11:04

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