ReferenceNumber tag lost is a few cases

[calberga]

This may not be exiftool's fault, I'm also posting to IrfanView as another suspect.

I have been using the ReferenceNumber tag to give me a unique id on an image when I change it's name or location in the directory tree.  After running a mass Keyword update on the files I noted that the ReferenceNumber had been lost from 14 out of 10,000+ files.  Only recently have I seen that ReferenceNumber is not allowed (by the standard) if ReferenceSource is not also set.  I have since set a dummy value for ReferenceSource, but at the time of the updating it was unset.

I may have used IrfanView on these files, but am not sure if that is the case.  I don't believe there were any warning messages about these files, but it is hard to find out, as the files are renamed before and renamed back after the Keyword setting, to avoid problems with accented characters. 

Would any programs expunge the ReferenceNumber value if ReferenceSource is not present?

[Phil Harvey]

I can speak for ExifTool, which would not remove this information unless you told it to.

- Phil

[calberga]

GOOD!!!!

Thanks

[StarGeek]

I just did a quick test and if you edit the IPTC data in Irfanview, you will lose the ReferenceNumber.