How to convert attachments to PDF/A?
Daniel Nashed – 7 June 2025 10:25:20
A customer asked me about how to convert attachments to PDF/A yesterday.
They use an existing business partner application, which isn't available any more.
The server would be a Domino on Linux server. So I am mainly looking for a Linux solution.
A main requirement is to detach the file, convert it and attach it to the document as an additional PDF attachment for current formats (mainly office).
What I found in a minute was LibreOffice in headless mode.
But it took a while to switch to PDF/A mode.
Converting to PDF/A format
It looks like there is no way to specify the options on command-line.
The only documented option I found was to set it in the GUI when exporting manually.
There was a tip to change the settings and that headless mode uses the settings specified (they are basically the same in the GUI and in headless mode).
So I set the options on my Windows desktop in the GUI and then updated the settings on my Linux machine.
The created files are now in PDF/A-3B format.
Does anyone else has experience in this area and other solutions?
I think LibreOffice and headless mode could be a good approach.
What I also saw is that there is a server mode.
Did anyone look into an integration like this already?
Here is what I found out so far:
Install LibeOffice on Ubuntu 24.04
apt update
apt install libreoffice
Change the configuration to create PDF/A-3B
SelectPdfVersion=3
UseLosslessCompression=true
vi ~/.config/libreoffice/4/user/registrymodifications.xcu
Note: I also set lossless compression to have sharp images.
Run a conversion for a PowerPoint file with configured settings
libreoffice --headless --convert-to pdf dachnug_2025_domino145.pptx
The presentations I tested look great. I have not done much other testing yet.
But this looks like a good way forward.
Validate the PDF
docker run --rm -v "$PWD":/data verapdf/cli verapdf /data/dachnug_2025_domino145.pdf
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