Every other phone app inverts a JPEG that Apple has already white-balanced, tone-curved and sharpened — which is why the colour never quite lands. Positive for iPhone would capture RAW sensor data instead, and invert it in log-density space with the same engine as the Mac app.
This app does not exist yet. There is nothing to download, and no date. We're deciding whether to build it, and the number of people on this list is most of the decision. Leave your email and you'll hear from us when there's something real to try — or if we decide against it, we'll tell you that instead.
Thanks — that's genuinely useful. Every signup moves this closer to being built.
In the meantime, if you own a flatbed scanner, the Mac app already does all of this properly.
Bayer sensor data straight off the camera as DNG, before the image pipeline bakes in white balance and a tone curve. A true digital negative, from a phone.
The same log-density inversion as the Mac app: sample the film base once, subtract the orange mask as a per-channel offset, flip.
Results are only as good as what's behind the film. The app would measure your light source and tell you when it isn't good enough — rather than quietly producing bad colour.
Point at a strip on a light pad, get the frames detected, deskewed and inverted — 35mm or 120, colour or black & white.
A colour negative's orange mask is a constant per-channel gain in linear space — exactly what auto-white-balance fights and loses to. In density space (d = −log₁₀(transmission)) it becomes a constant offset you can simply subtract. That maths doesn't care whether the light came through a flatbed's transparency unit or a light pad on your desk; it cares that the capture is linear. Phone cameras can emit linear RAW. Almost no phone scanning app uses it.
What we won't claim: a phone will not out-resolve a dedicated film scanner, and no amount of processing rescues a capture lit by a bad light source. The honest target is "genuinely good scans from a phone and a decent light pad", not "throw your scanner away".