[Export in PDFX1A will not impose]

Just to add to this: I have W10 v1903 and AP1.7.3.481. One extra query. If I add a single page early in the document, the page numbers from the twin master pages do not change sides L to R correctly. Just to check, I have tried the same things in  PPX9 and it works correctly. See the two attached files showing the PDF results.

SampleAP173481a.pdf

SamplePPX9a.pdf

[Export in PDFX1A will not impose]

I have a 28 page booklet in A5, therefore it requires A4+ paper as it has bleed, but not on all pages. It prints OK locally using "print" directly, but on trying to export to PDFX1A (or X3/4) for my pro printer the result is the spreads come out in normal sequence, not imposed for printing double-sided. Have I missed something as a new guy on the block, or is this a missing feature ?

[Image import SPP filetype?]

Thank you for your reply, MEB (muito obrigado). As there was a very clear family likeness in the desk top elements and arrangement in Affinity Photo to Serif Photo Plus, e.g. layers and filters etc., I thought the file types might be compatible or transferable. Maybe you will find other users migrating from Photo Plus and Draw Plus??? Good luck anyway with the new software.

Is there a recommended, least lossy, transfer format - apart from RAW of course?

[Image import SPP filetype?]

Was I wrong to expect that a native Serif file-type could be imported into Affinity Photo?