Rembrandt is a free open-source Lightroom alternative with on-device AI

Switching away from Adobe Lightroom has always forced a photographer to rebuild the whole image library, because no other editor would read the catalog. A new open-source project called Rembrandt now imports Lightroom Classic catalogs directly, runs its edits entirely on the user's own computer, and shipped a free installer for macOS, Windows and Linux this week.

Rembrandt was posted to Show HN by its author, who writes under the GitHub name thesnarkitecht. The repository is 10 days old, released under the GPL-3.0 licence, had reached 55 stars by the time the installer went up, and the Show HN post has received 42 points so far.

What ships today

The project is a desktop photo editor built as a Rust Tauri shell around a WebGL and WebGPU rendering pipeline, with raw file decoding handled by LibRaw. The README lists support for more than 1,000 camera raw formats, a scene-referred editing pipeline borrowed from darktable, non-destructive XMP sidecar edits, albums, ratings, keywords, batch operations, and merge tools for HDR, panorama and focus stacking.

Installers are published through GitHub Releases for macOS on Apple silicon and Intel, Windows on x64 and ARM, and Linux on x86_64 and arm64. A self-hosted server build is also available for teams that want to keep the whole library on their own hardware.

The author scopes the Lightroom comparison plainly. Rembrandt covers everyday raw editing, library work, masks, healing and presets. It does not have the Print, Book, Map or Web modules, face recognition, or tethered capture, and the README says so in its own comparison section.

The AI runs locally

Four features use machine learning and all four run on the device: subject, depth and background mask generation, denoise, super-resolution at 2x and 4x, and a refocus tool. A voice-command input accepts phrases like "golden hour, shadows +25" and converts them to adjustments.

Keeping the models on-device matters for a free editor, because a cloud model either costs the project money for every mask or asks the photographer for an API key. Rembrandt's models ship inside the installer and the README states they run with no network call, which is the only way a free local editor can advertise an AI feature set without a billing step.

The friction, as the author states it

Comments on the Show HN thread were divided. Several asked whether an AI-authored editor adds anything over established options like darktable and RawTherapee. The author's answer in the README is that Rembrandt "aims to be usable in five minutes, with fewer, broader controls" than those projects, which is a positioning claim rather than a measurement. The repository has 10 open issues and no forks on the first day the installer is out, so independent testing is thin.

Lightroom Classic plans start at around $10 a month on the Photography plan, so for a hobbyist with a modest library the question is whether the file compatibility and on-device AI are far enough along to leave. Rembrandt importing an existing catalog is the first thing to test, since the monthly subscription has been paying for the library at least as much as for the editor itself.

Source

Primary source: thesnarkitecht/rembrandt on GitHub, GPL-3.0. Discussion: Show HN, 42 points.