Overview

I'm a bit of a metadata junkie. I put considerable thought into my keywords and take full advantage of Lightroom's keyword hierarchy, synonyms and keyword export controls. I also like my Lightroom Plug-Ins. I have Photoshop CC, ON1 Photo 10 and the Nik Collection on my system at the moment. Over time, I noticed unexplained entries at the top level of my keyword hierarchy.  After a fair bit of head scratching, I discovered the “keyword pollution” was a byproduct of how I was round-tripping through my ON1 plugins.

A brief look at Lightroom keywords

Lightroom keywords can be arranged hierarchically. In this screenshot, you'll see I have the keyword “Peaceful” beneath “Emotion”, which in turn is beneath “Description”. I have several options for the “Peaceful” keyword selected so keywords above it in the hierarchy are exported, as well as any synonyms I may define. This arrangement really speeds up tagging my photos. I add a single keyword and inherit the parent keywords. This is incredibly useful for locations.

Hierarchical keywords in Lightroom

For top level keywords in my hierarchy, I deselect the Include on export option because keywords like Description or Place don't add much value for search engines.

Synonyms are excellent, too, if you're sharing your work online. The more variations on a keyword that are in your photo, the higher the chances of a search engine finding it. I'll get back to keyword synonyms soon. They get… interesting with round-tripping.

Round-tripping through Photo > Edit In…

When I launch plug-ins from Lightroom, most of the time I use the Photo > Edit In… menu. That's where most of my plug-ins live. Here is a before and after example of round-tripping a photo through ON1 Effects 10.

Original keyworded image on the left; round-tripped via Photo > Edit In… — they keywords are the same

The keywords on the round-tripped image are the same. All is good.

Round-tripping through File > Plug-in Extras

Now, what if I do the same thing using File > Plug-in Extras? I'll do the same exact treatment on the photo (not that it matters for keywords) just to be sure I'm not introducing some other variable to the procedure.

Round-tripped with File > Plug-in Extras; more keywords are added

Notice there are more keywords on the round-tripped image. An Emotion keyword is added as that is the parent keyword of Peaceful. Other keywords have been added as well. For example,  California, United States, and North America have appeared, courtesy of the San Diego keyword on my original photo.

Why the difference?

When using the File > Plug-in Extras menu, an “ON1 Photo exporting…” status appears in Lightroom. The plug-in is exporting the photo first and then launching the plug-in. During export, the hierarchical keywords are getting picked up. After editing in the plug-in, Lightroom evidently imports the exported file and picks up the additional keywords.

Why do I care, and what can I do?

You might not care. If you don't care about keywords, I'm surprised you've read this far. Also, if you don't use keyword synonyms, I'd advise you to ignore it. The net result is some photos in your catalog have more keyword tags than others, but when exported they'd have been included anyway. No real issues.

If you do use keyword synonyms, there are headaches with File > Plug-in Extras. Here, I've added the synonyms Tranquil and Serene to the Peaceful keyword. 

Keyword synonyms in Lightroom

As explained above, when I round-trip using File > Plug-in Extras from Lightroom the synonyms are exported. The synonyms are therefore in the photo that Lightroom will import, once your plug-in editing is complete:

Lightroom keyword hierarchy “polluted” after round-tripping with File > Plug-in Extras

Notice that Tranquil and Serene are in the Keyword List as well as tagged on the individual photo. Keyword pollution. Yuck. 

The sum of this is to use the Photo > Edit In… menu for round-tripping whenever possible. Sometimes you have no choice but to use the File > Plug-in Extras menu. With ON1, that's the only way to load multiple photos as layers into a single document. You are left with some keyword hierarchy cleanup (I'm in this camp) or living with something that might trouble your mild keyword OCD (the keyword flotsam irks me too much). It would be very nice if Lightroom offered a way to lock the keyword hierarchy like Aperture did. But, it doesn't, so no joy there. 

Is this behavior unique to ON1?

I'm not sure. Of all the plugins I've owned, ON1 is the only set that appears in both the Photo > Edit In… menu and the File > Plug-in Extras menu. This was true with Perfect Photo Suite 9 as well as Photo 10. I don't own enough plug-ins to check them all.

Do any of your plug-ins appear in both menus? If so, is there any difference in keyword behavior? Leave comments below and let us all know.

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