Need to create/modify and save to disk a read-only tag.

[BC]

My Google-foo and ChapGPT prompting skills have failed me in learning how to force the creation or modification of a read-only tag and save it using the ExifTool API.  Can you point me to a doc or topic that discusses this?

If it helps, my specific use case is creating the APP3 JPS tag which can already be read by ExifTool.  There are some apps, like "sView" that use this tag, and I am writing utilities that will leverage this tag as well.  I already have the official spec for the tag, so I know the correct values to use.

Bottom line is I really don't want to reinvent the wheel creating a custom tag that absolutely nobody else will know about, particularly where this established tag does exactly what I need -- the ability to create well formed JPS files.

[Phil Harvey]

ExifTool currently doesn't have the ability to write JPS APP3 metadata.

- Phil