@MickO Excellent! I love it when bright people figure out the answers to my questions even before I figure out enough to ask them. Thank you.
A reader wrote in today and got me thinking about how to write to an arbitrary Exif field in Photo Mechanic. My thought was to write the data to a (hopefully appropriate) IPTC field and then use Exiftool to copy it to the target Exif field. "Edit With" would allow the whole job to be completed in the Photo Mechanic interface. Your method worked perfectly. I assume you could do more or less the same thing in Windows with a batch file.
In sum (and for Google's benefit)
Using your method, you can write to any Exif field from Photo Mechanic.
You can do specific actions in the Exif like stripping all Exif data while leaving GPS information intact, or vice-versa.
You can write to or delete XMP fields that Photo Mechanic doesn't support, like removing the often troublesome and corrupted Photoshop Document Ancestors field.
Cheers.
-Carl
