Time Zone on DateTimeOriginal

Started by gheppell, February 16, 2024, 06:16:01 PM

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gheppell

Hello.

I am in the process of scanning old negatives then adding the correct metadata (time, geotag, etc).

After scanning and before any editing the field {File.MD.XMP::exif\DateTimeOriginal\DateTimeOriginal\0} inherits the time and time zone at which it was scanned.

Using TimeWiz, I change the Date Created and Date Subject Created which works fine.  However, the DateTimeOriginal Field only changes the date and time, NOT the time zone.  If the time zone of where the picture was taken is different than the timezone in which I am doing the scanning they become out of sync.  Is there an option to correct this?  thanks

Mario

I start with a file that shows this EXIF data:

[ExifIFD]      Date/Time Original              : 2024:02:12 10:25:13
[ExifIFD]      Offset Time Original            : +01:00
[ExifIFD]      Sub Sec Time Original          : 025

This is a 3rd (!) timestamp, not necessarily linked to date subject created and create date in XMP. ExifTool/IMatch use this timestamp to produce date subject created / create date for many file formats, though.

IMatch imports the file and produces the following XMP data:

Create Date 2024:02:12 10:25:13.025+01:00
Date Subject Created 2024:02:12 10:25:13.025+01:00

The variable {File.MD.XMP::photoshop\DateCreated\DateCreated\0|value:formatted} (note the value:formatted at the end to emit the time zone) shows.

2024:02:12 10:25:13.025+01:00

No I change the time zone offset of date subject created and create date to +03:00 and write back. This is important to map the modified XMP timestamps back to the native EXIF and legacy IPTC timestamps.

Now the file contains this EXIF data:

[ExifIFD]      Date/Time Original              : 2024:02:12 12:25:13
[ExifIFD]      Offset Time Original            : +03:00
[ExifIFD]      Sub Sec Time Original          : 025

and the variable {File.MD.XMP::photoshop\DateCreated\DateCreated\0|value:formatted} shows

2024:02:12 12:25:13.025+03:00

Seems to work just fine and correct.

Keep in mind that when you manipulate XMP data in IMatch, native metadata usually does not update, because mapping from XMP->EXIF, XMP->legacy IPTC, XMP->GPS is done during write back, not in the database.

That's why I recommend not to mix native metadata and XMP. Always stick to XMP for output and variables, unless you really need to access the native data for some reason. But then you must be aware of the complex relationships between EXIF, IPTC, XMP, GPS etc.
-- Mario
IMatch Developer
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