Answers to common questions about splitting and joining half-frame 35mm scans. If you don't find what you need, email us — a real person replies.
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joseph@optimizedmachining.comThe basics of the split-and-rejoin workflow.
Half-frame cameras expose two pictures in the space of one normal 35mm frame. When a lab scans that film, you usually get back a single wide image with two separate photographs side by side, divided by the dark strip of unexposed film between them.
Half-Frame Joiner finds that dark divider, splits the scan into its two real photographs, and lets you recombine any two of them into a new pair — ready to print at a standard photo size.
Open the Scans tab, select the scans you want from your photo library, and tap Split. Each scan becomes two individual frames.
From there, tap any two frames to see a live preview of how they'd look joined, then save it or open the editor to fine-tune the crop.
Yes — that's the point. Once your scans are split, you can pair any frame with any other frame, including ones from a completely different roll.
You can also use the Photo Gallery tab to combine two ordinary photos that were never part of a half-frame scan.
The app reads whatever your photo library holds, including JPEG, TIFF, HEIC, and RAW files from lab scans.
When saving, you can choose TIFF for maximum quality or JPEG for smaller files.
Getting a joined image ready for a lab.
Pick 4×6, 5×7, or Original before saving. The app composes the joined image to exactly that aspect ratio so the lab doesn't crop your photographs unexpectedly.
Original keeps the natural proportions of your own frames instead of forcing a print size.
That's intentional — it reproduces the unexposed strip of film that sits between two half-frame exposures, so a joined print looks like the original piece of film rather than two pictures pasted together.
Splitting is lossless — frames are cropped from the original scan at full resolution, never resampled.
When you compose to a fixed print size such as 4×6, the app scales and crops to fill that shape, which is what printing requires. Choosing TIFF avoids any additional compression.
If something doesn't look right.
The detector is deliberately cautious: if it isn't certain a scan holds two photographs, it leaves the image whole rather than cutting a real picture in half. This can happen when a frame is very dark, heavily edited, or the divider is faint.
Use the frame's edit tools to split it by hand — drag the divider to exactly where you want the cut.
Open Settings → Privacy & Security → Photos → Half-Frame Joiner on your iPhone and allow access. If you selected "Limited Access," only the photos you specifically chose will appear.
Finished images are saved to your device's Photos library, in your main library alongside your other pictures.
The Created tab inside the app also keeps a browsable history. Clearing that history removes the in-app list only — the photos themselves stay in your library.
Yes. Tap the ? button at the top of the Scans tab and choose View the Tour.
Short version: nothing leaves your phone.
None. Half-Frame Joiner has no accounts, no analytics, and makes no network requests at all. Your photographs are processed entirely on your device.
Full details are in the privacy policy.
Half-Frame Joiner