Posted by dellus on Dec 15, 2022; 11:32am
URL: https://forum.librecad.org/Print-preview-pdf-export-ISO-anomaly-tp5722289p5722290.html

What do you mean with "ISO"?
What is ecf? Sorry, not native English speakers don't know all abbreviations.

Looking at your pdf I imagine it might be an issue of scaling the print. Normally line widths stay as they are regardless of printing scale. In ancient CAD times a real pen was mounted to a plotter. So 0.25 mm stayed 0.25 mm even at 1/100 scale. As your pdf is A4 size I assume the content is scaled down, but not the pen width. If you print at 1/1, full size, it would look all right.
I recommend to print to pdf at full size, with a larger sheet size. Then you can print that pdf onto real paper scaled down.
Alternatively you can set "apply print scale to line width" in Print Preview.