Can't Seem to Print or Export Graphics as a Smaller Page Size

I’m working on a choral octavo. My client’s page size is 6.875" x 10.5". I have set this as a custom page size in the Layout Options. No matter what I’ve tried, whether I’m printing hard copy or exporting a PDF or PNG, the music enlarges to fit 8.5" x 11". I must be missing something. My client and I are both new to Dorico, and neither one of us has figured this out yet. Can someone walk me through the steps I need to take to get the music to print at the correct size, or recommend a tutorial?

Are you talking about the preview in the Print mode, or the actual exported graphic file itself?
And is it scaling, or just placed on a larger page?

The actual exported graphic file scales up. It’s printed on paper larger than the octavo sized page. I don’t know if this is causing it to scale up to fill out the page. This happens whether I’m printing directly from Dorico or exporting a PDF and then printing the PDF.

Can you provide an example project file, or a screenshot of the print window?

From Daniel last May:

Unfortunately, the PDFs I’ve exported and the physical printout also expand to fill 8.5" x 11".

It is still not clear, what you mean by expand.
This has to do with the printer driver of the computer you or your client is trying to print. If the print option is set to “adjust to page”, the printer will expand to the paper size in the printer. Try to look for the option “print in 100%” or “no adjustment”. PDFs have the ability to adjust to any size you will tell the printer driver to use.
The exact wording in the printer driver might vary from OS, Windows, Mac or wathever your client is using. Most people have their printer drivers set to “adjust to paper size” by default. That is probably why you are having an issue. Have a look at that setting.

First of all printing: Make sure that this is set to Custom Scale 100%, not Fit to Paper.

If I go to Graphics > PDF, I get this:
[file removed]
… regardless of how it looks in the Print preview area.

Thanks for this! I’ll share this info with my client, too.