Where NLP Metadata are stored?

I just want to confirm that the NLP metadata are stored only in the LrC catalogue, and not the DNG file itself? I rely a lot on this metadata and all my rolls are filled with all NLP metadata fields, so I want to be sure I keep them protected in case of any kind of disasters that can happen with the catalogue (although I have backups).

A quick test confirms that the metadata fields that can be edited under the “Negative Lab Pro” filter are neither written to XMP sidecars nor to files exported by LrC.


The NLP metadata for the original negatives is only stored with the LR catalogue. It’s important to keep a backup of the catalogue.

If you create positive TIF or JPEG copies (via NLP or via the NLP export settings in the Lightroom export panel), the metadata is stored to standard EXIF fields where available (and via descriptions where fields are not available).


Thanks, I guess this is the limitation of the Lightroom and it won’t allow you to store them in the actual DNGs.

I could have it overwrite the metadata in DNG… but the problem is that Lightroom relies on some of that data to know how to process your RAW image… for instance, if I overwrote the camera model to be the original film camera, then Lightroom wouldn’t know what to do with the RAW data… it uses the camera model in the EXIF as a way to know which RAW profiles are applicable to the image. Same goes with the lens.

We could use an IPTC tag to add things e.g. with comma separation. Not the whole load of NLP tags, but those that matter most. The importance is fairly subjective, but if we had a possibility to tag our personal favorites and hide the others, the overall helpfulness of NLP metadata could be improved and metadata could be written to files and sidecars.

No, don’t overwrite the existing metadata, just add new ones (if possible), maybe with the NLP prefix so we can distinguish them, but to be stored in the file itself, and not only in the catalogue.

I made a physical notes for each role since I learned that the NLP metadata are stored only in the LrC catalogue.

I agree with this! In my catalog I tag all my shots by their emulsion/film stock, and I would love to have Lightroom be able to export files with “Film Stock” as a custom field.

I am curious, you are talking about metadata, or also the “recipe” for NLP to develop the negative?

In that particular comment, I’m talking just about the standard EXIF metadata that is stored in the RAW file itself. I don’t want to overwrite that standard EXIF metadata because it could cause the RAW file to not be processed correctly by Lightroom in the future…

The “recipe” for NLP to develop a negative is stored with the LR Catalog.

Perfect, now I understand. So there is 0 problems editing in two computers, right? since it would read the data from the catalog. Sometimes I work on my laptop and other times on the desktop computer.

Right, as long as you are editing against the same catalog, it should work great!

Really useful set of posts. Been trying to solve something similar.

My brother and I are working through old family negatives - I’m scanning, cropping and converting (NLP’ing) and both the raw and an XMP are mirroring from my Synology box to his with a few hundred miles between us. I have a catalog with external photos at my end, he has the same at the other… and it all kinda works. I scan, he keywords and sorts dates etc. Read metadata back in and we each see the work of the other.

We’re trying to keep everything non destructive as far as possible.

With the raw and an XMP he can see the cropped, NLP’ed photo after import at his end but he can’t edit it himself in NLP because it doesn’t recognise that it’s already been converted… I see why now. The tone curve is standard LR metadata (can see it in the XMP), the NLP ‘converted’ flag is in the catalog… and that’s not mirroring.

Been having a look at LR/Transporter this evening using the info in https://forums.negativelabpro.com/t/metadata-import-into-nlp-custom-metadata-fields/5986/6

… but it all seems somewhat cumbersome.

Hoping I’m missing something but is there a way to say “for this bunch of images, export all the NLP data” so that somewhere else (another machine) you can say “for this bunch of photos, import all the NLP data” and have it just work?

I suspect we’ll just have to figure out how to share a catalog if we want to do it or accept that I NLP and he just does tagging (i.e. no remote NLP) but would be really useful to have an import/export function.

Am I just missing something obvious?


If you can just sync the Lightroom catalog itself between the two computer, that should work great!

If you google “Sharing a catalog in lightroom classic” that should give you some ideas.

Also, here’s a reddit thread with some ideas and solutions.

For images you’ve already shared, to add the NLP metadata to it, you might want to try going to “file > export as catalog.” In this case, since the images have already been shared, you can unselect “include Negatives” as this will save a ton of space and avoid duplication.

Then, when you load the catalog on the other computer, you will just need to point it to wherever the associated image folders are on other computer.


Fab - will have a play!