Fake scan - flatten PDF to single image

I have a partner who has paper fetish. He must have stamped & signed paper for everything. Even when this paper will never meet him in real life. So he demands scans of these papers (and original paper goes to a trash bin immediately after scan).

I'd like to save some trees by omitting these useless printed papers. I have stamps+signs in as fine quality transparent PNGs. So my first steps were placing this image into original (MS Office) document and save it as PDF.

But when you click on this inserted PNG in a PDF, it select it and it is obvious that it is not a part of "the paper".

This could be solved by flattening whole PDF into single image. PDF Creator is useless for this, because it ignores partial transparency and result of transparent PNG looks terrible. It could be solved by importing PDF into GIMP and exporting as PDF again. But this is really pain when there is lot of documents.

Is there some way how to automate it?

It would be great to be able add some small random tilt and "grungy filter" to make documents look more natural. (I'm able to do it manually, but tediousness in case of more documents is too high).

I'm running Win10.

Solution 1:

A PDF can be made directly into a fake-scanned one, although in most cases this will convert the pages into images and may increase the file-size.

There are websites that can do it, although this may not be a solution for multiple PDF files. Examples:

• PDF To Scanned PDF
• Make scanned

There are also products for doing that automatically, although they are usually commercial.
Example: Make PDF Look Scanned Software.

You could also automate it yourself using a free package such as ImageMagick.

See the post Make a pdf look scanned using ImageMagick where this command was proposed (among others):

convert -density 90 input.pdf -rotate 0.5 -attenuate 0.2 +noise Multiplicative -colorspace Gray output.pdf

You may find other suggestions in the post Simulate a scanned paper.