Today’s Question: I noticed that if I right-click on a keyword in the Keyword List [in Lightroom Classic] that there’s an option to edit the keyword. If I change the keyword itself with this option, what will happen to all the photos that I assigned the keyword to before changing the keyword?
Tim’s Quick Answer: If you edit the Keyword Name field for a keyword on the Keyword List in Lightroom Classic, the change will apply automatically to all photos that had the keyword assigned.
More Detail: The ability to edit the name of a keyword on the Keyword List found on the right panel in the Library module in Lightroom Classic is a simple and yet quite remarkable feature. When you edit a keyword in this way, all images that have the applicable keyword assigned to them will automatically be updated to reflect the updated keyword text.
For example, let’s assume after a photography trip to Paris, France, you added a keyword of “Eifel Tower” (with one “F” instead of two) to photos of that structure. The keyword would therefore appear on the Keyword List with the incorrect spelling. But all you need to do to correct the issue is right-click on the misspelled keyword, choose “Edit Keyword Tag” from the popup menu, correct the spelling in the Keyword Name field, and click the Save button. This will update the keyword not only on the keyword list, but also for all photos that had the keyword assigned to them.
There is one potential pitfall that requires a different approach. If you had assigned the keyword with the correct spelling to some images but the incorrect spelling for others, you can’t edit the misspelled keyword on the Keyword List. That’s because you would be changing the keyword to match another keyword that already exists.
In this case what you would need to do instead is first hover your mouse pointer over the keyword with the wrong spelling and click on the right-pointing arrow that appears to the right of that keyword. This will set a filter for all images with that keyword. Choose Edit > Select All from the menu to select all those images, and then turn on the checkbox for the version of the keyword with the correct spelling on the Keyword List. That will assign the correct version of the keyword to those images. You can then right-click on the keyword with the incorrect spelling on the Keyword List and choose “Delete” from the popup menu.
Both of these approaches provide great flexibility when you need to correct the spelling of keywords you had assigned to photos in Lightroom Classic.

