16 bit and 8 bit during processing

[Jaffa]

My understanding is a RAW file is processed in 16 bit in Affinity Photo Develop Persons by default (32 bit also available). 

Then, that file is then processed by default in 8 bit in Photo Persona, unless you have chosen under Document  to use 16 bit instead (during that current session).

What I have done with my imaginary document is to choose 16 bit to use to process in Photo Persona.

Once this document is finalised , when I then choose to Export as a JPEG, my understanding is that converts it to 8 bit.

Is my understanding correct please?

[walt.farrell]

7 hours ago, Jaffa said:

Once this document is finalised , when I then choose to Export as a JPEG, my understanding is that converts it to 8 bit.

Is my understanding correct please?

Yes, because JPG does not support 16-bit images. If you were to choose a different format, such as PNG or TIFF, you would have a choice of 16-bit or 8-bit at Export time using the More... dialog.

[Jaffa]

Just got back to this, Walt.  Very much appreciate your clarifying.  I suppose in view of my updated understanding, I should take anything to be printed as a TIFF, since presumably a TIFF will retain more of what I have spent time on, in improving the image.

[Fixx]

10 minutes ago, Jaffa said:

I suppose in view of my updated understanding, I should take anything to be printed as a TIFF, since presumably a TIFF will retain more of what I have spent time on, in improving the image.

Well, the difference may be too small to show. I generally use TIFF format in my printed matter (and most of the online materials too) as images will be compressed anyway to JPEG within PDF and I want to avoid repeated compressions, and it is always possible that I will have to open image again to make some corrections. But generally it should make no difference in normal print jobs. Only in very high end printing will benefit from 16-bit or uncompressed files. Of course JPEG compression quality must never be set too low.

[Jaffa]

Thanks Fixx, that gives me the info I need. 

I was aware that repeated opening of Jpegs can lose quality.  When I have finished my editing, then I export my image at 100% using Resampling as Lanczos 3 Non-Separable.