.afphoto files sizes 6x - just open and save

[wjgo]

Opening a 23mb .nef file, and then saving it as an .afphoto file - is 137Mb.  This seems nuts to me.  No changes.  Nothing done to it.  Open ned as 16 bit from Assistant,, save as, confirm develop, then save and explosion in file size.  Almost triple the size of .tiffs made with these .nef files.

Is there a way to operate with reasonable file sizes with just small adjustments to them?

[walt.farrell]

What release of Affinity Photo are you using?

[carl123]

Also, please supply a sample .nef file that shows the problem

[IanSG]

It doesn't seem to be specific to .nef files - I've tried this with a .nef, a .cr3 and a .dng file, all around 23 mb and they all saved as >180mb .afphoto files.  This was AP 1.8 under Win 10.

[walt.farrell]

One thing to remember is that a RAW file is much more storage efficient than a developed file., if

For a typical camera that uses a Bayer filter (as explained in James Ritson's Affinity Spotlight article, RAW, actually), each pixel requires 12 or 14 bits in the RAW file. But when developed to RGB/16, each pixel would require 48 bits. Or (I think) 64 when we include transparency information.

If we use the 48 number, then for a camera that uses Bayer filters, and that uses 12 bits per pixel, we already need 4x the space to record pixel information.

This isn't really accurate, because it ignores the possibility of using compression in the .afphoto file. But it may give a hint regarding the .afphoto files being significantly larger, as we haven't even looked at other data that Affinity Photo would maintain in the .afphoto file; we've only considered the actual data from the photo image so far.

One additional piece of data that Photo maintains is a copy of the original file as a Background Snapshot, though I'm not sure of the exact format of the copy.

I just developed a NEF file, and I see the following:

Original size: 19,225KB

Developed: 139,369KB (7.25 times bigger than NEF)

After removing the Background snapshot:
Developed: 111,266KB (5.8 times bigger than NEF, and 28,103KB smaller than the first developed version).

===

Net result, if my theories are correct: The .afphoto file should be at least 4x larger than the NEF. Developing, and removing the background snapshot, gets a file that is 5.8x bigger. That's within the ballpark that I would consider acceptable, as I know there has to be additional data present in the .afphoto file and it's close to the minimum expansion I'd expect. And this is ignoring the transparency data, which will account for some of that difference.

[Granddaddy]

There are many threads about huge afphoto files. I'm surprised @walt.farrell didn't mention them, perhaps because they pertained to jpg image files rather than nef RAW files.

In Ver 1.6, afphoto files were hardly larger than an original jpg file. Suddenly in Ver 1.7 afphoto files became 4 to 10 times larger. Various people explained this as being necessary and quite understandable. But it was also said this huge file size was the inadvertent result of last minute changes made to the file format to accommodate Affinity Publisher. Then suddenly in Ver 1.8, afphoto files have shrunk again to not much more than twice as large as original jpg files. Apparently the reasons given for huge file sizes in Ver 1.7 no longer apply.

The reasons for huge file sizes remain a mystery to me, though it seems related to the way APhoto was storing the jpg information and they have changed that again. It is possible to reduce an existing huge Ver 1.7 afphoto to the much smaller Ver 1.8 afphoto size by replacing the Background jpg with a new copy and saving in Ver 1.8 format. Since Serif does not document how the file format works, everyone seems free to make their own guesses. I just hope the enormous files of Ver 1.7 never return.

You might be interested in the threads involving jpg files saved as afphoto files, for instance, pointing to just a few:
https://forum.affinity.serif.com/index.php?/topic/108445-affinity-photo-file-sizes-much-smaller-with-ver-18/
https://forum.affinity.serif.com/index.php?/topic/109395-version-18-a-rant/&do=findComment&comment=592338
https://forum.affinity.serif.com/index.php?/topic/109471-use-aphoto-18-to-reduce-huge-size-of-aphoto-17-files/
https://forum.affinity.serif.com/index.php?/topic/86287-huge-file-size/&do=findComment&comment=572511

 

[R C-R]

1 hour ago, Granddaddy said:

The reasons for huge file sizes remain a mystery to me, though it seems related to the way APhoto was storing the jpg information and they have changed that again.

The Affinity apps do not store "jpg information" as such in native format files. Minimally, they store a full sized, decompressed version of the jpg image plus several mipmaps stored at progressively smaller sizes. As @walt.farrell mentioned, they usually also store a snapshot of the original background layer (which can be used with the Undo Brush Tool to selectively undo pixel edits). Some of this may be stored in a compressed format but it always uses lossless compression.

So among other things, highly compressed (low quality) jpgs will always be much, much larger if opened & saved in the native file format.