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No NAS? Cull from Any Local Folder or External SSD

By Ingo D ·

You do not need a NAS to cull fast. If your photo library lives on a local folder, an external SSD, or a working directory on your Mac, CullKit gives you the same rapid culling workflow that NAS owners get, with zero network setup.

Why is culling a local folder still so slow today?

Most photographers know the pain of a shoot-day folder. You plug in your SSD, open the folder, and you are staring at 800 RAW frames. What do you do? Scroll through Finder thumbnails that struggle with RAW previews? Import everything into Lightroom just to flag keepers, waiting through preview generation for images you will delete anyway? Open each file one at a time in Preview and manually note the keepers?

None of this is fast, and none of it writes usable metadata. Finder cannot rate. Lightroom import is heavy for a first-pass cull. And if you do rate inside Lightroom, those ratings live in the catalogue; they are not written to portable XMP sidecars that another tool can read. The result is friction before you have even opened your desktop editor.

Can I cull straight off an external SSD on an iPad?

Yes — this is one of the best reasons to cull on a tablet. Modern iPads and iPhones with USB-C read external SSDs and card readers directly through the Files system. Plug the drive into your iPad, point CullKit at the folder, and you’re culling at full resolution without copying anything to the device’s internal storage. The same works for a folder on the device itself or a working directory on your Mac.

  1. Connect the external SSD or card reader to your Mac, iPad, or iPhone (USB-C).
  2. Open CullKit and choose Local Folder.
  3. Pick your shoot directory.
  4. Start a culling session.

No Synology account. No SMB configuration. No network. Just your photos where they already live. RAW files, HEIC, video, and Live Photos all render; RAW and JPEG pairs are reviewed as one frame, so you are not double-culling the same shot.

How does the culling session work?

On iPhone and iPad, CullKit presents your frames as full-screen swipeable cards. Swipe right to pick a keeper; swipe left to reject. Configure swipe actions to match your workflow: one action for a star rating, another to flag a colour label, a third to clear. A quick-access bar sits at the bottom for star ratings and shortcuts, and auto-advance keeps you moving frame by frame without lifting a finger.

On Mac, the culling session is keyboard-driven. Tap number keys to rate 1 to 5. Press P to pick, X to reject, 0 to clear. Arrow keys step through the sequence. If you change your mind, undo rewinds the last action. If the app closes mid-cull, crash recovery picks up where you left off.

The session has three phases: start (choose beginning, unrated only, or filtered), rate (the main swipe or key pass), and batch review (check your selects before writing metadata). This lets you work in passes — a fast first sweep cuts the obvious discards; a second pass adds star ratings on what survived. On an 800-frame folder, a first pass takes around 25 minutes; a rating pass on the survivors adds 10–15 more. You finish with fully rated selects before Lightroom has even opened.

How do my ratings travel to Lightroom?

Every star, flag, colour label, and tag CullKit assigns is written to an XMP sidecar: a small metadata file that sits next to your RAW in the folder. Lightroom, Capture One, and Darktable all read standard XMP sidecars. So when you open your shoot folder in your desktop editor, your ratings are already there. No re-rating. No metadata export step. No import of a ratings file.

The sidecar stays with the image. Copy the folder to a different Mac, archive it to a backup drive, send it to a collaborator; the ratings travel with the files. That portability is the whole point of the sidecar standard — it’s why the same workflow works whether your photos live on a NAS, an SSD, or a local folder.

Does this work without any internet at all?

Completely. A local-folder cull needs no network connection, no account, and no cloud service. You can cull on a flight, in a remote location, or anywhere with no signal. CullKit does not upload your photos anywhere — no cloud processing, no library sync, no account that stores your metadata. Photos stay on your device and your drive. Ratings and sidecars are written to your own storage, in folders you control. For photographers who deliberately keep originals local for privacy, cost, and control, this is a genuine differentiator from cloud photo services. (More in the privacy FAQ.)

Local folder or NAS — which should I cull from?

If you already own a NAS, culling over SMB lets you review the library where it permanently lives, from any device on the network. But a local folder or external SSD has real advantages for a lot of photographers:

  • Speed on large RAWs. A directly attached SSD reads faster than a network share, so full-resolution previews appear instantly even on 45MP+ files.
  • No network at all. You can cull on a flight or on location with no Wi-Fi, then sync the folder (sidecars and all) to your NAS later.
  • Simplicity. No SMB address, no credentials, no enabling a service — pick the folder and go.

A common hybrid: cull on an external SSD the evening of the shoot, then copy the whole folder — RAWs and the XMP sidecars CullKit wrote — onto the NAS for archival. Because the ratings live in sidecar files inside the folder, they travel with the copy. Nothing has to be re-rated.

Does culling move or change my original files?

By default, no. Rating, flagging, and tagging only write small .xmp sidecar files next to your RAWs; the originals are never modified. CullKit can optionally move or delete files when you explicitly ask it to (for example, moving rejects to a separate folder during the batch-review phase), but those are deliberate actions you trigger — the culling pass itself is non-destructive. Your RAW files stay byte-for-byte as the camera wrote them.

Troubleshooting local-folder culling

  • The external drive doesn’t show up. Confirm the drive is mounted and readable in Finder (Mac) or the Files app (iPad/iPhone). Reformat exotic filesystems to exFAT or APFS if the OS can’t read them.
  • RAW files won’t preview. Most common RAW formats render; a brand-new camera’s RAW may need a CullKit update. JPEG and HEIC always render.
  • Sidecars aren’t appearing in Lightroom. Make sure you finished the session so metadata was written, then run Read Metadata from Files on the folder in Lightroom.
  • Ran out of space writing sidecars. XMP files are tiny (a few KB each), but a nearly full SSD can still fail the write — free a little space and re-run.

Tips for a faster local cull

A few habits make local-folder culling noticeably quicker:

  • Cull in two passes. A fast first pass rejects the obvious discards (blinks, misfires, near-duplicate burst frames). A second pass — switch the session to unrated only — adds star ratings to the survivors. Separating “is this usable?” from “how good is it?” stops you agonising over ratings on frames you were always going to drop.
  • Use the grid to pre-scan. Pinch out to see many thumbnails at once and spot whole sequences worth keeping or cutting before you enter full-screen review.
  • Configure your swipes once. Map swipe directions to the actions you use most (keep, reject, 5-star) so your thumb settles into a rhythm.
  • Let auto-advance carry you. Don’t tap “next” — each decision moves you forward automatically, which is where the speed comes from.
  • Cull soon after the shoot. A local folder on an SSD is the lowest-friction setup there is; doing the first pass the same evening keeps the edit moving while the shoot is fresh.

Try it for free

The free tier lets you browse any local folder or external SSD and view your images at full resolution. The Pro tier unlocks culling, star ratings, colour labels, XMP sidecar writing, and folder organisation, starting with a 7-day free trial, then a monthly or yearly subscription.

There is also a built-in demo mode with seeded sample data, so you can try the full swipe and keyboard culling experience before pointing CullKit at your own photos.

CullKit is native on iPhone, iPad, and Mac. It does not run on Android, Windows, or the web.

Download CullKit on the App Store

CullKit is independent software. Not affiliated with or endorsed by Synology, Adobe (Lightroom), Capture One, or Darktable. Compatibility claims only.

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