Hi Jay,
I tried reproducing with a 4k * 4k image, setting pixel size to 0.31 microns but I couldn't see any error unless I used the 4.0.0 export script, when I saw the same as you.
Are you sure you've updated to the latest export script? Actually, looking at our docs we don't make it very clear that this is part of the upgrade steps.
Either you need to copy the script to the server directory to replace the current one or $ bin/omero script replace as described at the bottom of the old page: https://figure.openmicroscopy.org/
Your export stack trace above appears to come from the 4.0.0 release (https://github.com/ome/omero-figure/blo ... _To_Pdf.py) and not the 4.0.2 fix https://github.com/ome/omero-figure/blo ... _To_Pdf.py
Hope that helps,
Will.