Sharon,
Just to better understand what you meant by "In general, the commas or semi-colons don't actually exist in the metadata at all" we tried a find on ";" and it brought up all images that had ; as a deliminator.
When the keywords you enter are delimited by the same character you have told PM that you're using, the metadata will not have any of the delimiters in it at all. Keywords in the metadata are a list of repeating fields. They usually don't have commas or semi-colons in them. When you use the opposite delimiter, then the list of repeating fields will have the delimiters present. Why is this? Because PM doesn't know where one keyword starts and ends and makes the entire set of keywords into a single keyword item and the incorrect delimiters will be present in the string of letters, spaces, and any other punctuation.
For instance if you have PM set to use commas as a delimiter and you enter:
"Sharon; Archives; Photography; Birds; Hummingbird"
Then the keywords list in the metadata will be a single item:
Sharon; Archives; Photography; Birds; Hummingbird
When you use exiftool to display the keywords on this item, it will find a single keyword in the keywords list and it will be:
Sharon; Archives; Photography; Birds; Hummingbird
Does that make sense?
Is there a way to get them to be uniform (all commas or all semicolons?) that's straightforward? Or does it not really matter that we use them interchangeably so long as we've done it consistently within a single image's keyword field on the IPTC panel? (all commas or all semicolons for each individual image)?
Yes. I explained how to do so in my last message. I'll repost it here:
Just do the Find (no replace) and then edit the IPTC Info for the images that are selected after the Find. You should be able to search for "Any of the words" and enter ", ;" as your Find text (don't enter the quotes though) and you should find both cases with one Find.
You would then open up the IPTC Info (click on the 'i' button that appears when you put your mouse cursor over a selected image), go to the Keywords field, and repair it manually. If you use the 'Save & ->' button, you should now get the next selected image loaded, ready for correction. Repeat until all are corrected.
HTH,
-Kirk