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.
https://extensions.libreoffice.org/?q=brochure&action_doExtensionSearch=Search
https://extensions.libreoffice.org/?q=trifold&action_doExtensionSearch=Search

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.

I am using LO 7.3.7.2 in Linux Mint. I am converting from ODT to PDF using LO’s built-in converter. To view and print the PDFs, I’m using Linux Mint’s built-in Document Reader. It seems that the resultant PDF is slightly smaller than the original ODT, meaning the edges of the text are closer to the center and the margins are larger, which is only a problem when I’m making the document more than one column. I tried an extension, as suggested by mariosv and got the same result. Everything was fine until I converted to PDF. I’m not convinced that the problem lies with Document Reader, though. Prior to last November, I was using a Mac computer with Preview for reading and printing PDFs and had the same problem.
I will attach the screen shots you requested shortly.

What happens if you open the pdf in Firefox and print at 100% scale from there?

Please also the pdf and writer source to check, if it depends on the pdf-viewer and to compare margins in Writer and pdf.
.
I assume you use only fonts, wich are installed on your OS. Font replacement may differ between LibreOffice and pdf-reader.

Wow! Success! I would never have thought of that. Especially because I have my documents printed at a print shop and they preferred that I email it rather than bring it on a thumb drive.

I’m about to go out of town and will provide all that you’ve asked for, Wanderer, next week.

And yes, I’m only using fonts installed on my computer. I tried converting from ODS to PDF using some online tools and not all the fonts I wanted were available there, leading to some very disappointing and annoying substitutions.