Sign All Pages

From time to time you may be requested to add your “hand written” signature to all pages of a document or contract.

But printing / signing / scanning every pages of a possibly long document is obviously not the best option.

Creating the signature

• Download and install some “handwritten” fonts you like

👉 convert -list font
  Font: Arista-Signature
    family: Arista Signature
    glyphs: /home/yannick/.local/share/fonts/Arista Signature.ttf

  Font: Autograf-PERSONAL-USE-ONLY
    family: Autograf PERSONAL USE ONLY
    glyphs: /home/yannick/.local/share/fonts/Autograf_PersonalUseOnly.ttf

• Create signature

I’m using convert command from imagemagick software

 👉 convert -background transparent -rotate -10 -fill darkblue -font Arista-Signature -size 300x200 -gravity center 'caption:AB' out.pdf

Creating the A4 page with the signature

PdfJam tool is used for this purpose

The pdfjam package makes available the pdfjam shell script that provides a simple interface to much of the functionality of the excellent pdfpages package (by Andreas Matthias) for LaTeX

The pdfjam script takes one or more PDF files (and/or JPG/PNG graphics files) as input, and produces one or more PDF files as output. It is useful for joining files together, selecting pages, reducing several source pages onto one output page, etc., etc.

• Install

 👉 sudo apt-get install texlive-extra-utils
 👉 dpkg -L texlive-extra-utils | grep bin | grep jam
/usr/bin/pdfjam

• Create a A4 signed page

--paper PAPERSPEC  (or simply --PAPERSPEC)
       Specify a LaTeX paper size, for example
       '--paper a4paper' or simply '--a4paper' for ISO A4 paper.
--scale 0.7   (to scale all input pages to 70% size)
--offset '1cm 0.5cm' (to offset all pages -- note the quotes!)

 👉 pdfjam --paper 'a4paper' --scale 0.2 --offset '7cm -12cm' signature.pdf

We have a page ready to be “merged” with existing pages of the document to sign.

Merging Pdf

This Debian Pdf will be our example document to add our signature into.

 👉 wget https://www.debian.org/releases/stable/i386/install.pdf.fr
 👉 file install.pdf.fr 
install.pdf.fr: PDF document, version 1.5
 👉 mv install.pdf.fr debian.pdf

To “merge” we are using pdftk

pdftk - A handy tool for manipulating PDF

 👉 sudo apt install pdftk
 👉 pdftk debian.pdf stamp signature-pdfjam.pdf output combined.pdf

stamp <stamp PDF filename | - | PROMPT>

This behaves just like the background operation except it overlays the stamp PDF page on top of the input PDF document’s pages. This works best if the stamp PDF page has a transparent background.

The signature is added to all pages of the document.

Apply to only some pages

In case only few specific pages needs to have the signature.

• Extract pages to add signature into

 👉 pdftk debian.pdf cat 35 output page35.pdf 

• Add signature to those pages

 👉 pdftk page35.pdf stamp signature-pdfjam.pdf output signedpage35.pdf

• Assemble non signed, with signed pages

 👉 pdftk A=debian.pdf B=signedpage35.pdf cat A1-34 B A36-end output signed-onlypage35.pdf

“Scanned” look

With the method above, the document will look as clean as it was before, lines can still be selected like into the original document, so recipient will be able to notice it’s not a “real” signature added on a scanned document.

Most people will not care, but in case some recipients care about it, we can add an extra step.

 👉 convert -density 130 signedpage35.pdf -rotate 0.33 -attenuate 0.15 +noise Multiplicative -colorspace Gray scanned-page35.pdf

This will make the document “not perfect” with some gray lines on the side and kind blurry like it could be with a scan process.

For large documents this may require to increase memory limit of ImageMagic.

 👉 identify -list resource
Resource limits:
  Width: 16KP
  Height: 16KP
  List length: 18.446744EP
  Area: 128MP
  Memory: 256MiB
  Map: 512MiB
  Disk: 1GiB
  File: 768
  Thread: 4
  Throttle: 0
  Time: unlimited

 👉 sudo vi /etc/ImageMagic-6/policy.xml
   <policy domain="resource" name="memory" value="256MiB"/>