Every frame written twice: the RAW and the JPEG beside it
· 4 min read
A camera set to RAW + JPEG writes both files on every shutter press, and neither file knows about the other. Three thousand frames from one day become six thousand files, and no filename tells you which two belong together. Dup's job here is to put each RAW back beside its JPEG, so you can keep the one your workflow actually opens.
A RAW and its JPEG are the same picture and different bytes
A Sony ARW and the JPEG the camera wrote next to it look identical and share nothing at all at the byte level, so MD5 and SHA-256 read them as two unrelated files. Tools that compare only within one format never put them side by side either. Dup fingerprints the decoded picture instead, so the pair arrives as one group no matter which format each half is in.
The RAW formats it reads
- Sony: ARW (A7, A7R, A9, A1)
- Fujifilm: RAF (X-T5, X-H2, X-Pro3, GFX)
- Canon: CR2, CR3 (R5, R6, 5D)
- Nikon: NEF (Z9, Z7, D850)
- Others: DNG (Leica, Pentax, Sigma, Hasselblad)
HEIC is matched against JPEG and RAW as well, which is what catches the frames you also took on a phone at the same event.
How a shoot goes through it
Drop the folder on the window, or browse to it. External drives work the same way, so a card offload can be cleaned up before it ever reaches Lightroom.
Every frame opens beside its sibling, with resolution, size and format underneath. What you are choosing between is on screen rather than hidden in a filename.
Tell Dup once whether you edit from RAW or deliver from JPEG. It marks the keeper in every group at once, and you review its choices instead of making thousands of them yourself.
Dup shows the size of what is about to go before it goes, and says plainly whether a file is heading for the Trash or being removed for good. Deletions land in the Trash by default, so the Finder can put them back.
Nothing leaves the machine
Every decode and every comparison happens on your Mac. No frame, no thumbnail and no piece of metadata is uploaded anywhere, which is the part that matters while a folder still holds a shoot the client has not seen.
Try it on one shoot
Free to try, with 250 MB of cleanup included. Nothing leaves your Mac, on any plan.