Search Replace Transfer
The custom fields
This plug-in adds 18 custom fields and a metadata panel to Lightroom including ones for the event name and for people. While these were originally intended for users migrating metadata from iView / Expression Media, you don’t need to have been an iView / Expression Media user to make use of them.
The extra fields are shown in the filter panel, and can be targeted by smart collections. They are also accessible by Search Replace Transfer's main functions, so you may use Transfer to populate one of the fields by copying across from the copyright field - meaning you can then search for entries in that field.
Changing the field names - for "experts"
If you don’t like the custom fields to be named Custom 01 etc, there is a way to change the names.
Just open PluginInitCustomFields.lua in a text editor such as Windows Notepad or TextWrangler. Here I have changed the name of Custom 01 to “My Custom Field Name”. For the changes to take effect, you’ll need to restart Lightroom, or reload the plug-in.
However, remember that this PluginInitCustomFields.lua file will be overwritten by updates of the plug-in, so you should keep your copy of the file in a safe place.
These custom fields are stored in the Lightroom catalogue and are never written to images themselves or to exported files. While that means they can be used for information which you do not want others to see, you can also see that as locking the information inside Lightroom and depending on this plug-in for accessing the fields. I’ve deliberately not encrypted the plug-in file where this metadata is defined.