@grby/nlpx

problem

negative lab pro, designed to process negative scans, stores its adjustments directly into the lightroom catalog. These settings can be lost when files are moved or a catalog becomes corrupted.

solution

nlpx is a two‑way sync tool for negative lab pro and the lightroom classic catalog.

It synchronizes sidecar files (.nlpx.json), allowing you to:

• restore negative adjustments back into the catalog at any time
• move or reorganize files without losing nlp data
• avoid keeping positive copies in lightroom, since they can be re‑created with the same settings on demand

limitations

• to allow moving files freely, synchronization is based on filenames
• each photo must therefore have a unique name (this is best practice anyway)
• suggested filename format: YYYYMMDD-HHMM-RR-NNN.CR3
• negatives must use the .CR3 extension
• important — before syncing data back into the catalog, make sure desired files have (at least default) negative lab pro adjustments
  • select desired photos and run negative lab pro
  • if any entries are present — good, they are ready for sync
  • otherwise — accept the dialog to create default entries, which will be overridden during sync

installation

$ pnpm add -g @grby/nlpx

usage

Make a backup of your lightroom catalog before syncing data back into it.

$ nlpx

$ nlpx --update-sidecar --catalog=<path> [--go] [--verbose] [--all]
$ nlpx --update-catalog --catalog=<path> [--go] [--verbose]

sync: catalog → sidecars

# close lightroom to ensure all adjustments are written to the catalog

$ cd ~/photos/album-123/
$ nlpx --update-sidecar --catalog=/Users/xyz/a/b/c/my-catalog.lrcat --verbose --all
# validate whether everything looks good

$ nlpx --update-sidecar --catalog=/Users/xyz/a/b/c/my-catalog.lrcat --verbose --all --go
$ ls -1
aaabbbccc.CR3
aaabbbccc.nlpx.json

sync: sidecars → catalog

# make a copy of your catalog and keep negative lab pro plugin closed!

$ cd ~/photos/album-123/
$ nlpx --update-catalog --catalog=/Users/xyz/a/b/c/my-catalog.lrcat --verbose
# validate whether everything looks good

$ nlpx --update-catalog --catalog=/Users/xyz/a/b/c/my-catalog.lrcat --verbose --go

warning

This software comes with no warranty — use at your own risk.
Always make a backup of your lightroom catalog before syncing data back.
Tested only with negative lab pro 3.0.2 and lightroom classic 14.3.1

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