[Solved] Printer files page dimensions

My book is set to A5 page format. The printer expects a printer pdf with an extra 3mm white space on all 4 sides. Is there a way to add this during pdf generation, or do I have to change each of my page style settings?

Version: 7.5.4.2 (X86_64) / LibreOffice Community
Build ID: 36ccfdc35048b057fd9854c757a8b67ec53977b6
CPU threads: 4; OS: Windows 10.0 Build 19045; UI render: Skia/Raster; VCL: win
Locale: de-DE (en_GB); UI: en-GB
Calc: threaded
Windows 10

As far as I know, exporting to PDF reproduces an exact copy of your document layout. So, I guess, the solution is to tweak your page styles.

You could look at Crop Mark extension, Crop mark » Extensions
I haven’t tried it.

If you know somebody with Adobe inDesign they could add bleed and crop marks to the pdf

Thanks for your responses.
@ajlittoz Yes, I feared as much. Of course it means maintaining two versions of a book if you want to publish in print and as PDF. I’m surprised this hasn’t been discussed here before (at least I didn’t find anything when searching before I posted my question) since this is a requirement of some of the major online printers in my country.
@EarnestAl Thanks for the tip. I downloaded it and read it through. Interesting, but as far as I can see, this places crop marks on an existing page. In my case I need to enlarge the pages.

You don’t need to maintain two versions of your book text, which would inevitably lead to discrepancies. The trick is to put styles, at list page styles, into two templates. When you want to publish your book, just change the template.

This is tricky to do manually but Template Changer extension makes the task easy. Among others, it allows you to base existing documents on a template even if you didn’t do it from start. But be cautious because document customised styles take precedence over those in the template. So, you’ll have to review carefully what you’ve done so far in your document.

I tried both first and second ways

For the odt, yes, you need to add a header if it hasn’t been done, enlarge each page style by the 3mm all round and adjust margins so page inside margins is original size, do the same for the 357d829f_cropmark.odt and then add the grouped marks to the header. A bit of a palaver if it isn’t done at the start of the process.

I also tried the pdf route using pdftk which is quite a bit simpler, requiring only to export the a5 document to pdf, set up the larger page in 357d829f_cropmark.odt, export to pdf, and run the command line from the correct directory. It worked quite well but if I remember correctly about pdftk, I think you lose some of the useful pdf functionality, active links, etc. but that doesn’t matter if it is just for printing.