Question on different XMP CreateDate values

[busbahnhof]

A lot of holiday pictures, three people, five cameras, six different time zones :-)

While working on a correction, I experienced the following. I changed the time of a picture to UTC ({File.MD.XMP::xmp\CreateDate\CreateDate\0}).

In the Metadata tab it shows: XMP Create Date 11.05.2009 12:50:58+00:00
In VarToy:
{File.MD.XMP::xmp\CreateDate\CreateDate\0} 11.05.2009 13:50:58
{File.MD.XMP::xmp\CreateDate\CreateDate\0|value:formatted} 2009:05:11 12:50:58+00:00

Metadata are written back to the file. Also restarted IM and updated the folder. For me, this looks kind of weird. I hope there is a good explanation for it. I couldn't find any.


Metadata analyst output:
Metadata Analyst Results. Version 2020.14.2. 18.3.2021 07:21:22
File analyzed: H:\Eigene Dateien\_bilder\freizeit\_usa\2009\12052009_dl1mgb\IMG_1589.jpg
Errors: 0
Warnings: 8

Warning: [GPS] Date missing.
Warning: [GPS] Time missing.
Warning: [GPS] Altitude missing.
Warning: [XMP] XMP-exif GPS Altitude missing.
Warning: [XMP] [ExifIFD]:UserComment not mapped to [XMP-dc]:Description (embedded).
Warning: [Detailed Validation] ExifIFD tag 0x9010 OffsetTime requires ExifVersion 0231 or higher
Warning: [Detailed Validation] ExifIFD tag 0x9012 OffsetTimeDigitized requires ExifVersion 0231 or higher
Warning: [Detailed Validation] ExifIFD tag 0x9011 OffsetTimeOriginal requires ExifVersion 0231 or higher

[Mario]

What is the question?
The ExifTool warnings can be ignored.

The time diff between the formatted and unformatted variable is because IMatch uses local time unless formatted etc.

[busbahnhof]

My not asked question is answered. Many thanks!

I wasn't aware that IM uses the local time instead of the correct time. This behaviour still sounds weird to me. But if it is consistent, I can life with it.

[Mario]

Variables format dates and times and numbers using the locale settings in Windows for the current user.
This means the date and time format used in your country, local time as you would see it on your clock etc.
When you format date and time variables using format, the locale is not applied.
See Variables for all details.

[busbahnhof]

So I would guess that IM shows the local time according to the creation date of the picture.

For example:
Picture was taken in April --> IM shows the creation time UTC+1
Picture was taken in August --> IM shows the creation time UTC+2

Or does IM use the current date on the computer? That means when I watch this picture in IM, it has a creation time of UTC+1 when I watch it in March, and it has a creation time UTC+2 when I watch it in August?

[Mario]

IMatch applies the local time zone and respects the time-zone in the metadata. Click into one of the dates in the Metadata Panel to see if the timestamp has a time-zone offset.

[busbahnhof]

Yes, there is an offset: {File.MD.Exif::Main\36880\OffsetTime\0} shows +01:00 (see also attached screenshot)

As far as I understand this is the offset between UTC and local time when the file was modified (i.e. from today). And that must be the reason why the offset cannot be changed. Right?

Maybe I am into small details right now, but I am about to align date/time for several thousand pictures. So I want to be sure I do the right thing.

[Mario]

IMatch does not care for the time stamps you name.
It only cares for data created and date subject created, which are filled once by IMatch as explained in How IMatch uses Date and Time Information
You are totally free to fill these timestamps with whatever time and date you like. Do it manually, do it automatically with the TimeWiz.
Note that +01:00 is UTC+1, which is the German time zone (unless daylight saving time is active). 12:00:00+02:00 displays as 11:00:00 in IMatch when you are in Germany.