Automating fake PDF signatures

Originally published at:


I usually scan to PNG, then insert an on-file scan of my signature. Not sure if that’s slower than having to figure out a bunch of coordinates.


Apple’s Preview PDF viewer holds a copy of your sig, that you can apply in a moment - and you can keep various versions of your sig and vary the size with each placement.


You might want to rethink your signature, @frauenfelder


I’ve done the “paste digital scan of your signature” thing dozens of times and have never had anyone question it. Then again, I am printing to a new PDF from that so I don’t know if that makes a difference.


xournal is an essential tool for dealing with “read-only” PDF forms


If you simply paste in the signature and return the original PDF, it’s visibly there as a floating layer. Hard to blame the person who rejects it.

One time only:

  • Scan a copy of your signature
  • Open it in any image-editing program, even one as basic as IrfanView
  • Add a transparent background layer
  • Select and delete the white background so the transparency shows through
  • Save as PNG, making sure to check the “preserve transparency” checkbox.


  • Paste your sig into any document, PDF or otherwise
  • “Print to PDF” and send the resulting file, not the original.

The hardest part of this is pasting the sig into the right place in the document and getting it to line up nicely; I’m not sure how a script makes that easier.


(this one uses hanko, but you could probably rig up an autopen.)


It might be Obama

1 Like

I’ve never had the OS X preview signature inserted document returned to me. I’ve done well into 6 figures of transactions this way and and no one has blinked an eye. Maybe it’s because I always export to a new PDF so there’s only one image layer.

1 Like

Seconded. xournal is one of my essential tools.

I’ve used the pseudo signature"font" in Adobe Reader’s “Fill and Sign” for hundreds of official documents*. Then just print to PDF and send back. Nobody’s ever cared enough to question it.

*Including .gov level stuff

1 Like

This topic was automatically closed after 5 days. New replies are no longer allowed.