Preserving EXIF through the Rawtherapee -> Gimp pipeline?

(Kodiak Firesmith) #1

Hi,
I’ve noticed that no matter how I try to do it, I can’t get a JPEG export from Gimp that includes EXIF data. It looks like EXIF goes in, but EXIF never comes back out.

I’ve tried:

  • Rawtherapee (5.3) -> [edit current image in external editor] -> Gimp (2.8) -> [export as jpeg]
  • Rawtherapee -> [save as 8bit tiff] -> [open tiff in Gimp] -> [export as jpeg]

Both of those flows strip EXIF from the TIFF before it can make it onto the JPEG. As you would expect, this screws up data in Flickr. I’ve seen similar threads via search, and they say to copy EXIF from a pre-Gimp JPEG into the post-Gimp JPEG, but those threads are old and I would hope that something as trivial as preserving EXIF would be doable within Gimp rather than adding a tedious and hackish workaround step after processing.

Am I missing anything? I’m pretty new to all this. Running all of it on Fedora 26, btw.

(Morgan Hardwood) #2

GIMP used to destroy all metadata until not too long ago. Make sure you’re using the latest GIMP 2.8.22 or 2.9.6.

I just tested and confirm that it works fine with RT-5.3 and GIMP-2.9.6.

You probably want to keep this enabled:
http://rawpedia.rawtherapee.com/Preferences#Metadata

(Kodiak Firesmith) #3

Ah, thanks so much for the reply. I’m running 2.8.22 which ships with Fedora 26. Appears to be the latest stable. Still strips EXIF (at least as I’m using it - could certainly be user error…)

(Mica) #4

You can try the gimp appimage 2.9.x from here: Community-built software

(François Collard) #5

I too am very concerned about this question. As a longtime Gimp user, I can tell this is not a Gimp issue. Even 2.6 and even former versions would keep EXIF without problems.

To me, the most serious issue is that TIFF files sent directly to Gimp by RawTherapee are without EXIF, even if ‘Copy Exif/IPTC/XMP unchanged to output file’ is checked.

I have used RawTherapee for years. Generally, as I really want to keep the EXIF in my xcf files, and I don’t want to edit an already altered JPEG file in Gimp, I export two files: a JPEG and a TIFF output, open the JPEG with Gimp, then add the TIFF as new layer in order to keep the processed image as lossless as possible, then delete or overwrite both output files;). Using Exiftool to transfer metadata from the raw file to the output is another workaround, but both are very messy and slow.

I don’t like Adobe products at all, but Lightroom can send to Gimp in PSD format so that metadata are kept and the image is not compressed with a lossy algorithm… RawTherapee developers, do you want to make me happy? Please, add such a feature, (maybe using xcf)!

(Mica) #6

Have you tried the gimp versions suggested by @Morgan_Hardwood? If not, then please do, and report back which versions are working and which are not.

(Morgan Hardwood) #7

Nonsense, check GIMP’s issue tracker.

If that is the case on your system, then write a proper bug report. http://rawpedia.rawtherapee.com/How_to_write_useful_bug_reports

  1. Open a raw file in RT,
  2. Hit Ctrl+e to send it to GIMP,
  3. Go to your temp folder and find the exported TIFF file,
  4. Upload both the raw file and the TIFF from the temp folder https://filebin.net/
  5. Include information about your operating system and version, which versions of GIMP and RT you’re using and where you downloaded them from.

I’m not saying RawTherapee has no issues with metadata - it does, I opened a bunch of bug reports myself - but metadata export to GIMP works fine using current versions of both programs, and if there is a problem then it should be properly reported.

(Kodiak Firesmith) #8

So it’s a Gimp thing with even the latest stable (2.8.22). I’ll chalk it up to that and leave it be. Thanks all!

(François Collard) #9

Sorry, but telling that I’m writing ‘nonsense’ looks a bit exaggerated. It makes me think of those horrible Trump’s tweets. I’m French; please don’t hurt my Continental politeness. You are “a modern man. A man for the millennium. Digital and smoke free”. I am not;)
Anyway, as an old man from the latter millennium, I believe in scientific objectivity and experimentation. I did the tests you suggested, and it appears that Gimp 2.8 does not properly import 16-bit TIFF from RawTherapee, but the files in the temp directory have these metadata indeed. Then I tried to send a raw processed file to Gimp 2.9, and EXIF metadata are kept within the “exported” files. Very good news for me, as I’m now using only Gimp 2.9 on Linux. And it is likely to work with DarkTable too…
This was not nonsense, but error; I have simply kept thinking that there were no EXIF in RT TIFF files for years, I have been wrong not testing it recently, because I had no issues with EXIF in Gimp with other formats supporting EXIF. I’m really happy to discover that I was wrong.

(Mica) #10

You two are actually from the same continent :wink: And hey, not all of us Americans are bad people! :slight_smile:

Gimp 2.8 can only handle 8 bit files. I believe gimp is down sampling your 16 bit tiffs to 8 bit and I’d wager the metadata is lost in the conversion by gimp to 8 bits, if it isn’t the bugs @Morgan_Hardwood already pointed out.

Gimp 2.9 can handle the 16 bit tiffs, as you have seen.

(François Collard) #11

:smiley:
Bad people using a language end up contaminating the language itself. It already happened with the German language in the 40s. This is a connotation effect, especially to a man like me who mostly studied literature…
I still love many of you Americans :wink: