Mobile · 2026
Lumi
A photo editor with 89 filters across 16 categories, whose film looks are simulated spectrally from the technical datasheets of real stocks paired with the print paper each was actually printed on, rather than approximated with a lookup table — reproducing the log-domain film curve, density that rises with saturation, halation and bloom, chroma resolved more coarsely than luma, three-layer grain, and flare and light leaks seeded per image. Face, body and makeup tools are each capped so results stay believable, and a manual brush works when detection does not. Everything runs on the device GPU through Metal, saving at up to 8192 pixels per side, and the app ships no networking code at all. Every feature is free — no in-app purchases, no subscription, no watermark — funded by ads shown only after a save.
At a glance
- 89
Filters in 16 categories
- Film
Real stock + print paper emulation
- Free
No IAP, no watermark
The challenge
Most "film" filters are a colour lookup table with grain pasted on top. They shift hue and stop there, so every photo lands in the same place and nothing behaves the way film behaves. Meanwhile a growing number of editors send your photos to a server to do the work.
Our approach
- 89 filters across 16 categories, headed by film emulated spectrally from the technical datasheets of real stocks paired with the print paper each was actually printed on — Portra 400, Gold 200, Pro 400H, Fuji C200 and Vision3 250D (film data referenced from spektrafilm, CC BY-SA 4.0)
- The layers a lookup table cannot reach: a film curve solved in the log domain around 18% grey, density that rises with saturation so vivid colour goes deep instead of glaring, halation and bloom as two separate diffusions, chroma resolved more coarsely than luma, three-layer grain that shifts with exposure and carries its own colour, and fringing, flare and light leaks seeded differently for every image
- Five face sliders, five body sliders and four makeup tools, each capped so a result never tips into the obviously edited, plus a manual brush that needs no detection at all
- Fully on-device: rendered on the GPU through Metal, previewed at 1080 targeting 60fps, and saved at up to 8192 pixels per side — the app ships no networking code, and 327 automated gates run before every release
The result
A free, watermark-free editor that behaves like film rather than imitating it, and never sends a photo anywhere.
Gallery
Brochure