The free, browser-based Lightroom alternative for RAW
Develop RAW photos right in your browser — lightweight, no subscription, no forced cloud. Your images stay on your device.
What Lumen does
All the key sliders
Exposure, contrast, highlights, shadows, whites, blacks, temperature, tint, vibrance, saturation — the ten classic Lightroom sliders, fully in the browser via WebGL2.
Real RAW files
CR2, CR3, NEF, ARW, RAF, DNG, RW2, ORF — opened directly in the app, no server round-trip. Embedded preview in under 5 seconds.
Local adjustments
Up to 4 linear gradient filters and 4 radial masks per image — exposure, contrast, saturation and temperature locally per region.
Auto-tone & auto-WB
One click — histogram analysis sets exposure, whites/blacks, contrast and white balance to sensible values. Great for flat out-of-camera RAWs.
Genre presets
Portrait, landscape, city, nature, animals, sport — moderate presets that bring out an image's character without overdoing it.
Your data
Self-hostable: Postgres + S3-compatible Garage, Keycloak for login. Your data stays yours — DELETE /me and JSON export built in.
Self-hosting
FastAPI · React 19 · WebGL2 · Postgres · Keycloak · Garage S3 · Docker Compose. Production-ready on a 4 GB VPS.
Lumen or Lightroom?
Lumen does not replace every pro workflow — but for RAW development without a subscription or forced cloud it covers the most important steps.
| Lumen · light | Adobe Lightroom | |
|---|---|---|
| Price | Free, self-hostable | Subscription from ~$10/month |
| Platform | Browser (WebGL2) | Desktop + cloud app |
| Your data | Stays with you | Adobe Creative Cloud |
| RAW in the browser | Yes | No (desktop) |
| Local masks | Linear + radial | Extensive (incl. AI) |
| Open source | Yes (AGPL-3.0) | No |
| No subscription / offline | Yes | No |
Frequently asked questions
What is Lumen?
Lumen is a free, self-hostable, browser-based RAW photo developer — a lightweight Lightroom alternative. RAW files are developed directly in the browser via WebGL2, with no forced cloud.
Which RAW formats does Lumen support?
CR2, CR3, NEF, ARW, RAF, DNG, RW2 and ORF — opened via libraw-wasm directly in the browser.
Is Lumen a Lightroom alternative?
Yes. Lumen offers the classic sliders (exposure, contrast, highlights, shadows, HSL, tone curve), local masks and presets — as a self-hostable, subscription-free web app.
Can I self-host Lumen?
Yes, via Docker Compose (FastAPI, React, Postgres, Keycloak, S3). Runs on a small VPS.
Does Lumen cost anything?
No. Lumen is free and self-hostable — no subscription, no mandatory cloud.
Do my images stay private?
Yes. Image processing runs locally in the browser; images stay on your device unless you deliberately save them to your own storage.
Is Lumen open source?
Yes. Lumen is licensed under AGPL-3.0 and available on GitHub — you can self-host, modify and redistribute it.
Do I need to install anything?
No. Lumen runs entirely in the browser via WebGL2 — no desktop install, no plugin.
Which cameras are supported?
RAW from Canon, Nikon, Sony, Fujifilm, Panasonic and Olympus — via the formats CR2, CR3, NEF, ARW, RAF, DNG, RW2 and ORF.