How to add keywords to lightroom from a textfile (after import)?

Question

I have a fairly large (20,000 photos) catalog. I'm trying to add keywords from the exif data that lightroom doesn't read, for instance any effects (like "pop color") applied to the photo.

Using exiftool I extracted all the data I want, and now I have a long text file like:

./2012-12-30/DSC03532.JPG   effect-Partial-Color-Blue
./2012-01-07/DSC00353.JPG   effect-Partial-Color-Yellow
...

And now I'm trying to figure out how to get that data into lightroom as keywords. I know I can write the keywords to the files directly and then have lightroom import them, but doing so wipes out all existing keywords I have on the files in lightroom.

Any insight?

Answer 1

First, use Lightroom's Save Metadata to File command (in the Metadata menu or via Ctrl/Cmd+S shortcut) to make sure the metadata saved in the JPG or XMP files (including keywords) are in sync with Lightroom's database.

Then add the desired EXIF data to the image files (for JPG files) or XMP sidecar files (for raw image files) using exiftool. For instance, to add the camera make as stored in the exif data to the keywords of a JPG file (with raw files it gets a tiny bit more complicated since you have to read from the raw file and write to the XMP file):

exiftool "-Keywords+<Make" <DIRECTORY>

Now select all images (Ctrl/Cmd+A to select all files if you are in Grid view), right-click and select Metadata > Read Metadata from File from the context menu.

Lightroom should now display the updated keywords.

Answer 2

If you are on Windows you can write a macro with Autoit or Autohotkey to go thru the list, select the correct photo in lightroom, apply the tags and move to the next. This can be done quite quickly if you use the macro recorder that records your actions, allowing you to customize and play them back.