How to convert from Writer to pdf without distortion

I am having trouble with the writer. I am making a three-column document in landscape mode. It allows me to select margins and column widths down to 0.02". I am placing photos in the 1st and 3rd columns and text in the center column. The center column is slightly wider than the other two so that I can make the document a tri-fold and am trying to center everything in its respective column. In the end, I convert to document into a pdf for printing. This conversion alters all my spacings and margin sizes, making the document slightly smaller overall and also moving everything slightly to the right, with the result being that the photos are way off center in the two side columns. How can I convert my very-precisely laid-out document into a pdf without all this distortion? Thank you.

There are several extensions about it.

Are you sure that your pdf reader is not resizing to fit margins when you print? That is default behavior for acrobat reader. Set to 100% in print dialogue

Please describe:

  1. What is your OS?
  2. What is your LibreOffice version?
  3. How exactly do you export to PDF - do you use LibreOffice’s PDF export feature, or do you maybe use a virtual PDF printer?
  4. Regarding the comment from @EarnestAl, attach a screenshot of the Writer document, and of the PDF display.

If that is a recent version of LibreOffice, and LibreOffice’s PDF export, then it would likely be a bug. PDF export is intended to produce an exact copy of the original document. One exception would be if you use an absent font - then both Writer, and PDF, would use some substitution, but they can happen to be different.