Lightroom Classic can build a small stand-in file for each photo, which lets you keep editing when the originals sit on a disconnected drive. The stand-in is a compact, lossy version of the image, so you can adjust it in the Develop module and the changes apply to the original once it reconnects.
What the Stand-In File Is
Lightroom’s feature name for these files is the Smart variant of its image proxy, and menus and checkboxes use that label. Each file is a reduced size version, roughly 2560 pixels on its long edge, stored in the catalog’s companion folder. Confirm the exact size in Adobe’s current documentation.
- It is much smaller than a raw file, so it takes little disk space.
- It lets Develop sliders work normally for most adjustments.
- It is not a replacement for the original when you need full resolution output.
How to Build Them
- During import, open the File Handling panel and tick the checkbox labeled Build Smart (the full label names the feature).
- For photos already in your catalog, select them in the Library module and choose the matching option from the Library menu’s proxy submenu.
- Wait for the progress bar at the top left to finish.
- Check the histogram: a small note under it shows when a stand-in file is being used.
Editing With the Originals Offline
- Disconnect the drive that holds the originals, or work on a laptop away from your main storage.
- Open the Library or Develop module and select an image.
- Adjust exposure, color, crop and local edits as usual.
- Apply flags, labels and keywords the same way.
- Reconnect the drive later. The catalog links the edits to the originals again.
What to Expect
| Task | With stand-in file only |
|---|---|
| Develop sliders | Works |
| Culling and keywords | Works |
| Export at full size | Needs the original file |
| Zoom to 100 percent | Limited detail |
Some very fine tasks, such as sharpening judgments and noise reduction at full zoom, are better made when the original is connected.
Good Habits
- Back up the catalog regularly, since it records every edit.
- Do not move or rename originals outside Lightroom if you want the link to hold.
- Build the stand-in files for any shoot you may edit while traveling.
FAQ
Can I export from stand-in files alone?
Lightroom can export a reduced size file from them, which is handy for quick sharing, but full quality output needs the original.
Do they affect catalog size?
They add to the catalog’s companion folder, so leave room on the drive that holds your catalog.
The Short Version
Build the stand-in files before you disconnect your originals, edit normally, and reconnect later to sync everything. Keep your catalog backed up, and export final images when the originals are connected.
