Incorrect timestamps - Adding offsets?

Troubleshooting
1

Hi!

I’ve tried importing some photos and find that the timestamps, which while displaying correctly in Finder, are incorrect in Tropy (v1.16.2, arm64 macOS).

Here’s some of the exif data for one of the photos:

[System]        FileModifyDate        : 2024:06:26 10:47:25-04:00 # Current timezone, EDT (GMT-4)
[System]        FileAccessDate        : 2024:09:11 17:16:40-04:00
[System]        FileInodeChangeDate   : 2024:06:26 10:47:25-04:00
[IFD0]          ModifyDate            : 2024:06:26 11:47:25
[ExifIFD]       DateTimeOriginal      : 2024:06:26 11:47:25 # Original timezone, ADT (GMT-3)
[ExifIFD]       CreateDate            : 2024:06:26 11:47:25
[ExifIFD]       OffsetTime            : -03:00
[ExifIFD]       OffsetTimeOriginal    : -03:00

These photos show up as having been created 2024-06-26 04:56:00, -7 hours before they were in fact.

I tried this as well with a photo I just took:

[System]       FileModifyDate          : 2024:09:11 17:21:47-04:00
[System]       FileAccessDate          : 2024:09:11 17:22:22-04:00
[System]       FileInodeChangeDate     : 2024:09:11 17:22:20-04:00
[IFD0]         ModifyDate              : 2024:09:11 17:21:47
[ExifIFD]      DateTimeOriginal        : 2024:09:11 17:21:47
[ExifIFD]      CreateDate              : 2024:09:11 17:21:47
[ExifIFD]      OffsetTime              : -04:00
[ExifIFD]      OffsetTimeOriginal      : -04:00

This photo shows up in Tropy as 2024-09-11 09:21, or -8 before the factual time they were created.

From this it would appear that Tropy is calculating the time offset by adding both the offset of the original image (-3 in the first case, -4 in the second) and at ingest (-4 in both cases) - or am I missing something?

I am new to Tropy so forgive me if I’ve missed a very obvious toggle! Thanks!

2

Thanks for reporting!

Can you clarify which timestamps in Tropy you’re using for the comparison? The EXIF metadata properties?

3

Thanks for replying!

The timestamps in Tropy are from the item pane on the right side with a photo selected within a list, under Metadata and with Tropy Photo selected in the Photo section:

Screenshot 2024-09-12 at 07.31.17

This is the pane for the photo in the first example above. The “Date” field should be displaying 11:47 AM in ADT/GMT-3 or 10:47 AM in EDT/GMT-4 - 14:47 GMT - otherwise the information is correct.

The exif data is the output of:

exiftool -time:all -G1 -a -s foo.JPG

So, I’d imagine you can find a good deal of the information you’re looking for property-wise in the exiftool man file.

4

Also, turning the “Assume Exif timestamps use local timezone” preference on or off does not change this behaviour!

5

Great, thanks. Without going into too much detail, in this case DateTimeOriginal from the EXIF data should be used (that’s unless there’s also XMP metadata embedded there). So I think that your analysis is spot on and there’s an issue converting the timezone offset correctly. We’ll look into it and fix it in the upcoming release!

1 Like
6

Wonderful, will watch for that!