Bug 416994

Summary: Unexpected handling of DateTimeOriginal and DateTimeDigitized
Product: [Applications] digikam Reporter: Raymond Johnson <johnson>
Component: Metadata-DateAssignee: Digikam Developers <digikam-bugs-null>
Status: REPORTED ---    
Severity: minor CC: caulier.gilles, metzpinguin
Priority: NOR    
Version First Reported In: 7.0.0   
Target Milestone: ---   
Platform: unspecified   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: sample image with different DateTimeOriginal and DateTimeDigitized dates
Animated GIF of date-changing behavior

Description Raymond Johnson 2020-01-31 19:19:42 UTC 
SUMMARY
I have scanned images in which Exif.Image.DateTime is set by the scanner to be the time of scanning. I use Exiv2 commands to manually copy that to Exif.Photo.DateTimeDigitized and also to set the original capture time in Exif.Photo.DateTimeOriginal. It looks like this:

$ exiv2 -pt -g DateTime rj_20040709_063.jpg
Exif.Image.DateTime                          Ascii      20  2015:10:11 13:40:12
Exif.Photo.DateTimeOriginal                  Ascii      20  2004:07:09 00:00:17
Exif.Photo.DateTimeDigitized                 Ascii      20  2015:10:11 13:40:12

When the image is loaded into DigiKam, all seems fine. The Exif tab of the metadata panel correctly shows both the Original and Digitized dates under the photograph information. However, if I choose Item->Write Metadata to File (I'm writing to sidecars only), then the photograph information shows the Original date for *both* DateTimeOriginal and DateTimeDigitized.

If I configure Digikam metadata so that timestamps are not written to the metadata, this behavior does not happen.

STEPS TO REPRODUCE
1. Configure DK metadata to write timestamps to metadata (I believe this is the default)
2. Add an image to DK that has different times for Exif.Photo.DateTimeOriginal and Exif.Photo.DateTimeDigitized
3. Perform the action Item->Write Metadata to File
4. See that the photograph information in the Exif tab of the metadata panel shows the original date for both "Date and Time (digitized)" and "Date and Time (original)"

OBSERVED RESULT
The digitized time is mistakenly overwritten by the original time.

EXPECTED RESULT
The digitized time should not be overwritten by the original time.

SOFTWARE/OS VERSIONS
Using the digikam-7.0.0-beta2-1-x86-64 AppImage on Pop OS! 19.10.

ADDITIONAL INFORMATION
This is annoying for those of us who obsess over metadata of scanned photos, but since it may not matter for digital photos where original and digitized is the same, and it seems that turning off timestamps in the metadata settings avoids the problem, this is probably a minor bug.
Comment 1 Maik Qualmann 2020-01-31 19:45:05 UTC 
Hmm, in a first attempt here I can not reproduce the problem, the original date is preserved. It could be a problem with the AppImage because the locale is not working properly. Can you please provide a test image?

Maik
Comment 2 Raymond Johnson 2020-01-31 19:57:28 UTC 
Created attachment 125578 [details]
sample image with different DateTimeOriginal and DateTimeDigitized dates

Here is an image for testing.
Comment 3 Raymond Johnson 2020-01-31 19:58:51 UTC 
(In reply to Maik Qualmann from comment #1)
> Hmm, in a first attempt here I can not reproduce the problem, the original
> date is preserved. It could be a problem with the AppImage because the
> locale is not working properly. Can you please provide a test image?
> 
> Maik

Oh, and in case I wasn't clear, the problem isn't that the original date is preserved. It's that the digitized date is replaced.
Comment 4 Maik Qualmann 2020-01-31 20:17:33 UTC 
The digitization date 2015-10-11 does not change here either. Maybe upload the sidecar file for testing so I can compare the content.

Maik
Comment 5 Raymond Johnson 2020-01-31 20:24:14 UTC 
Created attachment 125580 [details]
Animated GIF of date-changing behavior

Maybe it's easiest to show you the behavior in this animated gif.
Comment 6 Maik Qualmann 2020-01-31 21:53:56 UTC 
Ok, I hadn't activated the writing of the time stamp. The problem only occurs with sidecars. Exiv2 performs a mapping to interpret from XMP to Exif. And this mapping uses Xmp.CreateDate for Exif.Photo.DateTimeDigitized. At the moment I don't see a solution to the problem. For me, the mapping in parts is faulty from Exiv2. The right candidate would be Xmp.exif.DateTimeDigitized.

Maik
Comment 7 caulier.gilles 2020-08-04 07:02:07 UTC 
digiKam 7.0.0 stable release is now published:

https://www.digikam.org/news/2020-07-19-7.0.0_release_announcement/

We need a fresh feedback on this file using this version.

Best Regards

Gilles Caulier
Comment 8 caulier.gilles 2023-05-03 21:17:16 UTC 
@Raymond Johnson

digiKam 8.0.0 is out. This entry still valid with this release ?

Best regards

Gilles Caulier
Comment 9 caulier.gilles 2023-10-11 14:53:27 UTC 
@Raymond Johnson,

What's about this file using current 8.2.0 AppImage Linux bundle ? It's
reproducible ?

https://files.kde.org/digikam/

Thanks in advance

Gilles Caulier