[Apologies for hijacking this thread for what turns out to be a different but related issue!]
I suspect something similar is happening with image creation times in the XMP sidecar if metadata sync is on. I just turned it back on having upgraded to 5.3.0, and soon turned it off again - other apps reading the XMPs after PL had saved changes were seeing creation dates changed by my local time zone offset, which is +10:00. I think this used to work correctly with PL 5.1. I haven’t had time to dig into what is changed yet, but I will do so. I’m using a variety of Panasonic cameras.
Update: I just did a quick before-and-after comparison using Exiftool. The XMP before PL has changed it has:
[XMP-exif] Date/Time Original : 2022:06:15 07:32:06.701
After changing the star rating in PL, it has:
[XMP-exif] Date/Time Original : 2022:06:14 21:32:06.7-00:00
So PL is adjusting the time to UTC and adding a zero timezone offset that was not there before, and the other apps fail to adjust for that - they assume this field is ‘local time’ even in the presence of the zero time offset.
Looking at the raw with Exiftool, which in this case is from a Panasonic TZ220, I see these related items:
[Composite] Create Date : 2022:06:15 07:32:06.701+10:00
[Composite] Date/Time Original : 2022:06:15 07:32:06.701+10:00
[Composite] Modify Date : 2022:06:15 07:32:06.701+10:00
[ExifIFD] Create Date : 2022:06:15 07:32:06
[ExifIFD] Date/Time Original : 2022:06:15 07:32:06
[ExifIFD] Offset Time : +10:00
[ExifIFD] Offset Time Digitized : +10:00
[ExifIFD] Offset Time Original : +10:00
[IFD0] Modify Date : 2022:06:15 07:32:06
Maybe the other apps are reading ExifIFD:CreateDate and ignoring the OffsetTime that goes with it, but PL is being more rigorous, and since the offset time is missing in the XMP, PL assumes UTC.
Or it could be that since the EXIF CreateDate spec seems to be ‘string’ rather than ‘date’, PL is wrong to add a timezone offset to it.
Or I could have read this wrong, and it’s something else!
Either way, I still can’t use metadata sync.
And another update: if I change the shot time in PL by adding 10 hours, it shows up at the right time in my other apps. The XMP file then contains the right time (according to the other apps), with a zero time offset, like this:
[XMP-exif] Date/Time Original : 2022:06:15 07:32:06.7-00:00
Alternatively, just adding my local timezone offset (+10:00) to the Date/Time Original instead of +00:00 fixes it. PL should be getting that from the operating system, or allowing me to specify it.
Using an idea triggered by @Europat’s comment in this thread, I have found that running PL with its app timezone set to GMT seems to sort things out for the XMPs - on a Mac, this means I have to use this command in a terminal window to start PL:
TZ=GMT open /Applications/DXOPhotoLab5.app
More testing is needed, but I don’t think this workaround will allow me to leave Metadata Sync on if I am to access any images PL originally saw with my correct local timezone.
Updated yet again: It appears that if PL creates the XMP file in the first place, rather than another app, it works as it should. This led me to creating the XMPs and adding the timezone of the image to DateTimeOriginal using Exiftool at import time (for which I use a script anyway), and this seemed to provide a workaround for my particular circumstances - but it doesn’t survive back-and-forth changes between the apps (PL and Mylio, in my case).