Hi!
I am running version 10.05 of the ExifTool on Windows 7. I have run into a perplexing issue. I have a Python script that uses the ExifTool to write custom XMP tags (Dublin Core namespace) to a Photoshop file. The script just runs the command line command from within Python.
However, sometimes I need to overwrite my tags with new data. I can query one of the tags:
>exiftool.exe -XMP-dc:FMID test.psd
Fmid : 1234
However, when I try to assign a new value or just delete the old value, I get these results:
>exiftool.exe -XMP-dc:FMID=1235 test.psd
Warning: Tag 'FMID' does not exist
Nothing to do.
>exiftool.exe -XMP-dc:FMID=1235 -overwrite_original test.psd
Warning: Tag 'FMID' does not exist
Nothing to do.
>exiftool.exe -XMP-dc:FMID= -overwrite_original test.psd
Warning: Tag 'FMID' does not exist
Nothing to do.
Changing "-XMP-dc:FMID" to "-XMP-dc:Fmid" does not help.
However, I do write data (which I call "keywords") to the Subject tag. I can query and delete that.
>exiftool.exe -XMP-dc:Subject test.psd
Subject : test, test, test
>exiftool.exe -XMP-dc:Subject= -overwrite_original test.psd
1 image files updated
Of course the Subject tag is not a custom tag. It is a tag that Photoshop normally assigns to the image. Any ideas on what I am doing wrong?
From the XMP tag page (http://www.exiftool.org/TagNames/XMP.html):
"ExifTool will extract XMP information even if it is not listed in these tables, but other tags are not writable unless added as user-defined tags in the ExifTool config file."
Exiftool can't write to this tag without a config file that defines it. So there should be a config file someplace that your script references.
Okay. I found the config file. Now it works! Thanks![
> exiftool.exe -config exiftool.config -XMP-dc:FMID test.psd
Loaded!
FMID : 1234
> exiftool.exe -config exiftool.config -XMP-dc:FMID= -overwrite_original test.psd
Loaded!
1 image files updated
> exiftool.exe -config exiftool.config -XMP-dc:FMID test.psd
Loaded!
Happy to have helped. ;D