[Astro processing: The image on screen, before or after develop, is totally different from the mess that is created as a saved file.]

Thanks guys. It appears, if I export it as a "Siril built in sRGB" profile (which I hadn't looked at in the drop down box), it saves (or exports I should say) properly. I don't know why because I have no idea what any of this jargon means, I just wish to use the app but apps are developed by people who seem to think we all like to research every single tech/geek aspect about saving files and doing coding etc.

Anyhow, thanks again. Appreciated. If you hadn't prompted, I'd have been no further forward.

[Astro processing: The image on screen, before or after develop, is totally different from the mess that is created as a saved file.]

That said Walt, you say you see the same in Photos on your ipad? So your ipad is showing the messed up version? So why would that be? Yes, if I open in Affinity, it is correct, as you say, but I need to be able to reopen in Siril (or Preview or Photos) and get what I expect to get. 

Another thing to set me straight: If I open a clean, RAW image from my camera, yes, Affinity has opened it  in the Develop persona. However, if I wish to then use layers etc, can I process it in the develop persona first then transfer to the other 'persona' for layers etc (I forget the names of the personas), do further processing then back to develop persona for final tweaks and develop?

[Astro processing: The image on screen, before or after develop, is totally different from the mess that is created as a saved file.]

Thanks Walt, I'll have to take another look at what exactly, I'm doing then. I'm very new to Affinity (and processing in general). I'll work on it and see if I can identify the issue (sounds like it could revolve around what you suggest but I need to check). If it doesn't resolve, I'll return and give a full breakdown on the 'workflow'. If it does resolve it, I'll let you know.

[Astro processing: The image on screen, before or after develop, is totally different from the mess that is created as a saved file.]

Well that's odd because this is what I get when I open the tiff file (either opened on my 2017 i5 Macbook or 2021 M1 Mac Mini). This is a screenshot...

[Astro processing: The image on screen, before or after develop, is totally different from the mess that is created as a saved file.]

I take a Starless (by Starnet) tiff file from Siril. I import into Affinity (though this happens with many files I create - astro or not) and process it. What looks good on the screen, I then go into the Develop persona, develop it (without any further processing or with additional  processing in the develop persona) and what is then saved (I reopen in Siril or Preview) and it is a completely different rendition VEIL.tiffand a total mess. Affinity has you believe you have a perfectly processed and developed image but what it then saves is garbage. What is going on?

Below is the screenshot of what I see that I think I'm saving on the desktop. Granted, not an excellent image of the Veil nebula (very little integration time) but it's something.  The  actual file is ridiculous!

[Alignment not working in the stacking feature.]

I bought Affinity also expecting it to be able to stack from watching James Ritson tutorials. I had a number of photos of Jupiter which could be stacked fine on other programs but, when attempting  both ways of adding the photos into Affinity, the result was absolutely terrible. While the individual subs could be worked on in Affinity because, when loading them individually,  Affinity would simply show  the photo correctly exposed;  When it came to stacking, Affinity would totally overexpose the planet while I noticed that the moons would show up in multiple orientations because Affinity had rotated the photos. When i tried "File:Stack" it's hard to explain how that came out but, frankly, it was just a mess.

I knew Affinity could not stack from a video file but I had entirely anticipated it would do a good job of a bright planet with individual subs, given it could do  the job well - it  appears although I have yet to try - on deep sky objects which are far less bright. The stacking feature was one of the main (if not  the main) reasons I purchased it.