Writing xmp-dc:description to a PNG doesn't show up in Photoshop (JPEG works)

[martinrwilson]

I am trying to write a tag to a PNG file that will be displayed in the IPTC Content->Description field in Photoshop (File->File info...) and Adobe Bridge. (Writing the value to IPTC:Description doesn't do it!)
I entered a value into that field in Photoshop and saved the file to see which field it's written to.

Using exiftool -a -G1 my-image.png I can see the value in XMP-dc:Description.

So I tried writing a value to this tag as follows:
exiftool -xmp-dc:description="The description" my-image.png
However, the value is not shown in Photoshop/Bridge.

If I do exactly the same using a JPEG, e.g.
exiftool -xmp-dc:description="The description" my-image.jpg
It works fine and I see the value in the IPTC Content->Description field in Photoshop/Bridge.

I appreciate that this is probably an Adobe issue but does anyone know enough about this to be able to explain to me why it's not working for PNGs? And for bonus points, how I can make it work?!

[Phil Harvey]

When you write it with Photoshop, do you see it with Photoshop if you re-load the image?

If so, then the problem is likely that you need to use the API PNGEarlyXMP option when writing:

exiftool -api pngearlyxmp ...

See the PNGEarlyXMP option in the API documentation for details.

(yes, it is a jungle out there...)

- Phil

[martinrwilson]

Yep, that works - thanks for your speedy and helpful response Phil!