PDF export - flattening and transparent layers

I recently completed a series of music exercise books using Dorico. I’ve been attempting to publish hardcopies via the Amazon Createspace service, in order to print on demand. Unfortunately, they are seemingly unable to print the books without error. On about 50% of my pages, noteheads get replaced with time signatures or clefs and vice versa, and other similar character displacement issues. Their Tech Support advice is as follows:

After connecting with our TS team, they found that the errors are due to transparencies and or layers not being flattened before the publisher submits their file. Because we do not have the parent file we cannot be much more specific. Flattening transparencies or layers applies to the document in its entirety not just a couple pages. We have reviewed the file and we are unfamiliar with the PDF creator being used so we cannot give step by step instructions with that software.However, we would recommend going to the original file, flatten layers, transparencies, and ensure all fonts are embedded.

If you are having trouble understanding how to flatten the layers/transparencies/ and embed the fonts we recommend looking up the PDF software you are using and seeing the specific instructions on how to do so.

Now, because these are books with 30 musical exercises all in 12 keys (i.e. with 12 flows per exercise, so key signatures look good), I made 30 PDFs and combined them in Adobe Acrobat DC. Everything is set to be flattened etc in there. (It became impractical to try and combine 360+ flows in a single Dorico document - it became very laggy at around 60 flows, not to mention the organizational nightmare of that many flows! How about either support for Flow Groups, or ability to combine multiple Dorico documents?)

I’ve read that everything in Dorico has fonts embedded, which would obviously have to be the case for music to appear correctly on other computers, but can you comment on whether everything is being flattened upon PDF export?

I’ve had a fantastic time learning Dorico over the course of this project, and one of the big draws has been the ability to cut out InDesign for page layout. I would hate to have to go back and export 133 pages of book as image files and assemble in InDesign…

Dorico’s PDF files don’t support either layers or transparency, so I’m afraid I don’t think this explanation from Amazon can be quite right.

If you are finding some symbols being replaced by other ones, that sounds very much like a font embedding problem. Unfortunately you cannot force Dorico not to embed fonts and instead create every shape using outlines when exporting PDFs, though that would very probably solve the problem, since if your PDF files consisted only of curves and other primitive shapes rather than embedded glyphs, then there could be no mysterious substitution problems when it comes to the production process at Amazon.

I don’t have a recent version of Acrobat DC to test this on, but from what I have read, if you’re producing your final PDF in Acrobat, you can go to the Flattener Preview dialog and choose to convert all fonts in the PDF to outlines, which should ensure that you get the desired symbols in your output when printed by Amazon.

Thank you for the clarification regarding transparency and layers, or lack thereof, in the PDF export. That’s extremely helpful to know. I’ve already attempted to convert to outlines in Acrobat, although my next stop will be Adobe Support, to have them confirm the best settings for me.