Background image layers in pdf

[XChangeGirl]

Hello. I am working with pdfs where every page has a dark layer behind the layer that contains the main text. The pdfs are usually of scanned books, though I don't know under what circumstances they were scanned. The dark layer appears to be an artifact of the scanning process, and contains no useful information. I can access the layer and delete it, on a page by page basis. But I am hoping there is a way to do the entire document at once.

For some reason I'm unable to embed it into this post, but this screen cap shows what I'm talking about.

Any ideas how I might proceed with getting rid of that layer across the entire doc?

Thank you!

[Dimitar - PDF-XChange]

Hello XChangeGirl,

Please try both of these tools and see if they help for this case:

Regards.

[XChangeGirl]

Thanks for the reply and suggestion, Dimitar. It hadn't occurred to me to try either watermarks or backgrounds. Unfortunately, neither of those were it.

I put together pdf that shows the issue. Hopefully it made it through.

Thanks again!

pdf background layer.pdf

(65.54 KiB) Downloaded 49 times

[Willy Van Nuffel]

It seems like it goes about scanned pages with two image-layers and one text-layer (as a result from OCR/Optical Character Recognition).

So, what you can do is

1) remove the image-layers:
- via the Content-pane (View-ribbon > Panes) > Options > Select > Images,
- then press the Delete-key on the keyboard

2) make the text layer visible:
- via the Content page > Options > Select > Text,
- then in the Text Tools/Format-ribbon, change the "Fill Color" from none to black

Take care in case there are pictures in the text that should remain.
In case there are none, then there is no problem.

Does that help ?

[Daniel - PDF-XChange]

Hello,

It does seems that Willy's solution here will be the only one to take in this case. The watermark/background removal tools rely on the content items being specifically flagged as such, and cannot remove items which are not defined as one of those content types.
His method should work, but it will be quite involved.
If you have any control over it, and the scanner in use offers a background removal function, that may be a better option, to prevent this issue at its source.

Kind regards,

[XChangeGirl]

Ok. Thank you all for your help.

It does seem like it would be a tedious manual process.

Is there any way to bring a layer forward, so that it became the top layer and could just be deleted without drilling down to it.

I'm trying to think if maybe a series of otherwise manual steps could be turned into an AutoHotKey script that could be run, if necessary, on all the pages. Or am I just grasping at straws?

These scans weren't made by me. I'm jus trying to make them more readable.

Thanks.

[Willy Van Nuffel]

Hi,

Thanks for your reply.

Did you already try the method I described ?
It should not take more than a few seconds, much less than the time it takes to describe it and to read it.

Select images, selects all the images on all the pages in your PDF (a question of seconds).
One press on the Delete key makes them all disappear (also in a few seconds).
Select text, selects all the text in your PDF, and giving it a fill-color goes also very fast.

Maybe the result is not as good as I would expect ?
Or, there may be many documents that need to be dealt with ?

Kind regards.

[Daniel - PDF-XChange]

Hello,

A slightly faster method might be to open the Content panel, and select the images present there for deletion, but depending on the structure of each document, as Willy warned, it is possible that some of those images do contain visible "text" even if it is not real text content. As such, It would be risky to make any larger bulk edits without a manual process, as it could lead to some major data loss if done without enough attention to detial.

Kind regards,