Re-Importing the Photo Keyword List into Lightroom

There is a some confusion amongst many Lightroom users about what happens when you re-import a Keyword List to Lightroom. This worked example will show what is really taking place during the import process.

Let's assume you already have some photos in your Lightroom catalog, and that some of them are keyworded with keywords in your Keyword List. You export your Keyword List, make some changes to it, and re-import it. Does this cause any problems? Read on to find the answer to that question, and see what actually happens to the Lightroom internal database.

Cleaning out Previous Keywords
Before starting the Keyword List installation, it is a good idea to remove all currently unused keywords from Lightroom. To do this, start the Lightroom program and then click on 'Metadata > Purge Unused Keywords'. This operation can take quite a few minutes if you already have a large list of installed Keywords. A progress bar will show how the operation is progressing.

Installing a Keyword Library in Lightroom
Click 'Metadata > Import Keywords'. Navigate to and select your keyword-list text file. Click Open (Windows) or Choose (Mac OS). Once the import has completed, your keyword list can be seen in the 'Keyword Tags' window. Initially, only the top categories of the Keyword List will be showing, but if you click on the triangles to the left of the main category words they will expand to show the sub-categories and deeper categories as well.

Exporting and Re-Importing a Keyword List

So let us start the demonstration. The image below shows a basic keyword list that I am using for this test.

The next image shows the same list imported into Lightroom, and displayed in the 'Keyword Tags' panel. The numbers on the right show that some of the keywords have been assigned to photos in the Lightroom catalog.

Note that the 'actual' keywords that have been assigned were 'Fox Terrier', 'Baboon', and 'Lowland Tapir'. These words are Children to their Parent Categories, but once the children were assigned to keywords, the parent and grandparent keywords are automatically included as well. Three photos were assigned one keyword each, and one photo was assigned two keywords, which is why 'Mammal' shows 4 photos even though the photo-counts for 'Fox Terrier', 'Baboon', and 'Lowland Tapir' total 5.

I now modify the original list by including two children to the keyword 'Rodent'. The image below shows these changes.

This new list is then re-imported into Lightroom. The image below shows how Lightroom reacts to these changes.

All is still OK. The same keywords as before are still assigned to the same photos, even though two extra lines have been added to the database.

I now modify the list a second time. The additional Rodents have been removed, and the list is reset to what it originally was. Then, another change is made: the keyword 'Ape' and its child 'Baboon' has been removed from its parent 'Primate' keyword and moved to the 'Pets' keyword.

I purge the unwanted and unused rodents from the catalog by clicking 'Metadata > Purge Unused Keywords'. The modified list is then re-imported to Lightroom, and the results are shown in the image below. We notice that even though the list no longer has an entry for 'Primate > Ape > Baboon', it is still shown in the 'Keyword Tags' panel, with one photo assigned to it, as before. Listed under the 'Pets' keyword is the moved keyword and child 'Ape > Baboon', but as expected, this moved 'Baboon' has not been automatically assigned to any photo by Lightroom, which treats each of the two Baboons as separate entities.

If we want to assign the keyword 'Baboon' to another photo, and start typing that word in the 'Keywording > Keyword Tags' panel on the right of the screen, Lightroom will show, after a few letters of the word has been entered, that there are now two different 'Baboon' keywords available, and will display their hierarchy for you to identify which one you prefer to choose. The image below shows this happening:

This example demonstrates a potential problem. If some photos in your catalog are tagged with the first 'Baboon' keyword, and other photos are tagged with the second 'Baboon' keyword, there is likely to be some confusion when searching for all Baboon photos in your collection.

As a final step in this demonstration, I export the Lightroom keyword list by clicking 'Metadata > Export Keywords'. This gives us a chance to examine the current catalog that Lightroom is using. Here is what it now looks like: