Description tag: How is this tag propagated?

[thrinn]

I do not really understand the propagation rules for the Description tag.

After setting up a simple Metadata layout containing the Description tags from XMP xmp, XMP Dublin Core, and Composite, I entered different texts into each of the three tags (see screenshot 002).
When applying the changes, the image is marked with the pen icon for unwritten metadata. The metadata browser still shows the texts I entered. In the Vartoy App, I also see the same texts. Nothing strange yet.

But I trigger the metadata writeback the result is as shown in screenshot 003: The "XMP xmp" description disappeared. The "Dublin Core" description is still correct. The "Composite" description now contains the text from the "Dublin Core".

Conclusion: The "Dublin Core" tag is propagated to the "Composite" tag. The "XMP xmp" tag is cleared (?).

But from the following quote I had expected the "XMP xmp" tag to be used, not the "Dublin Core" tag.

I have switched the default "Description" tag to use the XMP metadata tag, because Composite Description is replicated into XMP, but does not support multi-language XMP tags. The "Default" Metadata Template so when you reload it into the Metadata Panel you get this tag.

Is this the expected behaviour?

(And yes, I switched the Metadata language to Neutral).



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[JohnZeman]

XMP Dublin Core Description works best for me, and that seems to be what your tests indicate as well.

I can understand the confusion though, both the

{File.MD.XMP::dc\description\Description\0} tag (of which I have two of in my metadata variable selector although only one works)

and

{File.MD.XMP::tiff\ImageDescription\ImageDescription\0}

tag are XMP descriptions.

[Mario]

The dublin core is the offical XMP description tag and is the one that should be used (The IMatch 5 Standard Description tag uses this).

Updating this tag (when the database is set to Neutral language) updates also the
+ Composite\Description
+ EXIF\Image Description tag.
+ IPTC\Caption/Abstract

this is in accordance with the MWG guidelines, section 5.2:

Information for the description property is available in the following properties:
Exif ImageDescription (270, 0x010E)
IPTC Caption (IIM 2:120, 0x0278)
XMP (dc:description["x-default"])

where x-default refers to the neutral language. XMP descriptions made in languages other than neutral apparently are not covered.