LightCraft

Your photos. Your pixels. Your machine.

Photo library and raw development; an open-source, clean-room reimplementation of Adobe Lightroom, rebuilt in pure Rust.
Native on macOS, Windows and Linux. In the browser via WebAssembly. Drivable end to end by AI agents over MCP.

LightCraft on getartcraft.com · ArtCraft · All Crafting Apps

_{Ansel Adams, "The Tetons and the Snake River" (1942). Public domain, U.S. National Archives. Developed in LightCraft.}

[!NOTE] ArtCraft is a community of artists from all walks of life. Digital, generative, music, games — if you make things, you're one of us. Come say hi on Discord.

Editing · Color grading · Before & after · Masking · Presets · Library · Agents & MCP · Performance · Status · Quick start · Roadmap · Crafting Apps

Edit like you mean it

LightCraft is a complete darkroom in a single native app. Every adjustment is non-destructive, so your originals are never touched. Every slider renders through a scene-referred, wide-gamut, 32-bit float pipeline: highlights roll off like film, shadows open up without halos, and colour stays clean from capture to export.

_{A gentle S on the RGB point curve, right under the Light sliders. Ansel Adams, 1942 (public domain).}

Color grading, the cinematic way

Split-tone shadows, midtones and highlights independently with drag-anywhere colour wheels. Below, Dorothea Lange's Migrant Mother gets a warm, print-like tone (highlights at 42°, shadows at 28°) in two drags.

_{Shadows, midtones and highlights wheels in the Color panel. Dorothea Lange, "Migrant Mother" (1936). Public domain, Library of Congress.}

Before & after

Hold \ to peek at the original, press Y for side by side, or Shift+Y for a split view. Every image below is a real screenshot of LightCraft, captured automatically by an agent through the control channel.

Masking that goes where you point

Paint with a Brush (size, feather, flow, density, erase), drop Linear and Radial Gradients with draggable pins, or select by Luminance Range, Color Range, Sky, Subject and Background. Combine components with Add / Subtract / Intersect, invert any of them, and dial in 15 local adjustments per mask (Temp, Tint, Exposure, Contrast, Highlights, Shadows, Whites, Blacks, Texture, Clarity, Dehaze, Hue, Saturation, Sharpness, Noise) plus an overall Amount.

_{A radial "Sun glow" mask (Temp +40, Exposure +0.50) layered over a linear "Sky" mask. Photo from LightCraft's procedurally generated demo library.}

Presets, profiles & the Color Mixer

Eighteen hand-built presets ship in the box (Golden Hour, Teal & Orange, Faded Matte, Selenium Tone, Crisp Landscape and more), each with an Amount slider from 0 to 200 %. Save your own from any group of settings, mark favourites, and copy, paste or sync edits across a whole selection with exactly the groups you choose.

_{The Presets column next to the 8-band Color Mixer. Photo from the demo library.}

Organize everything

A library that stays out of your way: All Photos, Recently Added, Picks, By Date, Albums nested in Folders, and Recently Deleted. Rate with 0–5, flag with P / X / U, colour-label with 6–9. Search understands fields: rating:>3 flag:pick iso:>800 camera:x2 date:2026-04 keyword:mountains. Every view sorts by capture date, import date, edit date, name, rating or size. The justified Photo Grid and Square Grid views are virtualized, so they stay smooth whether you have forty photos or forty thousand.

Built for agents

Every menu item, slider, brush stroke, crop handle and keystroke in LightCraft is a command with a stable id and JSON parameters. The UI, the keyboard, the CLI, a JSON-lines control channel and an MCP server all dispatch through the same entry point. An agent can cull a shoot, develop it, mask a sky and export it, and see the result.

lightcraft --control 7980 ~/Pictures/trip

{"method": "engine.execute", "params": {"command": "photo.flag",  "params": {"flag": "pick"}}}
{"method": "engine.execute", "params": {"command": "develop.set", "params": {"values": {"light.highlights": -45, "light.shadows": 38}}}}
{"method": "engine.execute", "params": {"command": "mask.add",    "params": {"kind": "radial", "center": [0.62, 0.4], "rx": 0.2, "ry": 0.14}}}
{"method": "ui.clickWidget",   "params": {"id": "slider:effects.clarity"}}       // drive any widget by name
{"method": "ui.pointer",       "params": {"events": [{"kind":"down","x":0.2,"y":0.3}, {"kind":"up","x":0.4,"y":0.3}]}}
{"method": "ui.screenshot",    "params": {"path": "after.png"}}

• 91 engine commands and 48 UI commands. List them all with engine.commands; read every slider's range, default and current value with develop.controls.

• MCP server. lightcraft-cli mcp gives Claude (or any MCP client) ~100 tools: import, query, develop, mask, render (returned as an image), export. It runs headless, or attached to the running app with screenshots, clicks and gestures. See docs/mcp.md.

  cargo build --release -p lightcraft-cli
  claude mcp add lightcraft -- "$PWD/target/release/lightcraft-cli" mcp ~/Pictures/shoot          # headless
  claude mcp add lightcraft-app -- "$PWD/target/release/lightcraft-cli" mcp --connect 127.0.0.1:7980  # live app
  

• Scriptable CLI: lightcraft-cli run --import in.dng develop.set control=light.exposure value=0.7 app.export path=out.jpg longEdge=2048 runs any chain of commands (headless, on a saved library, or against the running app) and prints one JSON result per command; lightcraft-cli render in.dng -o out.jpg --set light.exposure=0.7 --preset ….

• Undo for everything, including agent actions: a slider drag (or a scripted burst of updates) is one undo step.

• Every widget is addressable (ui.widgets) and clickable by name, so agents operate the real UI, not a side door.

• The screenshots in this README were produced end to end by the docs/showcase/ scripts. Protocol reference: docs/control-protocol.md.

Fast, native, private

• Pure Rust, no C. Our own RAW decoders (DNG, Canon CR2, Sony ARW, Nikon NEF, Fujifilm RAF incl. X-Trans, Panasonic RW2, Pentax PEF, Olympus ORF), our own colour science, our own pipeline. JPEG, PNG, TIFF, WebP, PSD composites and JPEG XL open today.
• Scene-referred & wide-gamut. Linear Rec.2020 float internally, Bradford-adapted white balance, gamut mapping instead of clipping, a filmic shoulder for raw and pixel-exact pass-through for JPEGs you haven't touched.
• Resolution-independent edits. Radii and brush sizes are relative to the image, so a 400 px preview, your 5K display and a 60 MP export look the same.
• GPU-accelerated, CPU-exact. The whole develop pipeline runs as wgpu compute kernels (Metal / Vulkan / DX12), checked against the CPU pipeline to within 1/255. On a 24 MP raw (Apple M4 Pro): a slider update re-renders in ~4 ms, a cold 2.5 MP loupe in ~30 ms, and a full-size export in ~0.3 s including a parallel JPEG encode. Without a GPU the same pipeline runs on all CPU cores, redoing only the stages a slider affects.
• Instant culling. Opening a raw shows its embedded camera preview or cached render within ~0.1 s while the full render follows (~0.2–0.5 s for 24 MP). The next and previous photos are prepared in the background, so stepping through a shoot takes ~50 ms per photo.
• Background rendering. A worker pool renders the loupe, before/after and every visible thumbnail off the UI thread: drafts during drags, full quality on release.
• Local-first. No account, no cloud, no telemetry, no subscription. Your catalog is an append-only log of human-readable operations you can diff, back up or replay.

Feature status

LightCraft is young and moving fast; see the roadmap for estimates. The detailed, row-by-row Lightroom parity tracker (every feature, menu item and shortcut with its status, evidence and the top gaps) is docs/parity.md.

_{✅ works today · 🚧 in progress · ⬜ not started}

Quick start

git clone https://github.com/storytold/lightcraft && cd lightcraft
cargo run --release -p lightcraft                       # opens your library (~/Pictures/LightCraft Library; a new one starts with demo photos)
cargo run --release -p lightcraft -- ~/Pictures/trip    # import your photos (folders are scanned, duplicates skipped)
cargo run --release -p lightcraft -- --memory           # a throwaway in-memory demo session (writes nothing)
cargo run --release -p lightcraft -- --control 7980     # with the automation channel
cargo xtask web --serve                                 # the same app in the browser: http://127.0.0.1:8080/
cargo run --release -p lightcraft-cli -- render photo.jpg -o out.jpg --set light.exposure=0.5
cargo xtask ci                                          # fmt, clippy, tests, layering, wasm checks

The web build needs the wasm32-unknown-unknown target and the matching wasm-bindgen CLI (cargo xtask web prints the exact install command); see docs/web.md.

Keyboard: G grid · D detail · E edit · C crop · M masking · Shift+P presets · \ original · Y before/after · Z zoom · J clipping · ⌘Z undo · ⌘/ all shortcuts.

How it's built

An engine-first Cargo workspace of small, tested crates with enforced layering (cargo xtask layers): geom, color, raster, tiff → raw, codecs, meta, develop → pipeline → catalog → engine → ui-egui. The egui frontend is one swappable crate; nothing below it knows a UI exists. mcp and the apps (lightcraft, lightcraft-cli) sit on top of engine.

Contributing

Humans and agents follow the same rules, so read AGENTS.md first. The short version:

• Clean-room. Never read Adobe binaries or GPL raw/photo code (darktable, RawTherapee, LibRaw, rawspeed, dcraw…); work from public specs and black-box observation.
• No Adobe assets, ever: no icons, screenshots, presets, profiles, LUTs or fonts from Adobe products. Every image, icon and font in the repo is original, public domain, Creative Commons, OFL or permissively licensed, and has an entry in assets/ATTRIBUTION.md added in the same commit.
• Pure Rust, enforced crate layering, everything is a command, and cargo xtask ci green before every commit (one task id per commit).

Questions, ideas or a bug you'd like to talk through first? Bring them to Discord.

The Crafting Apps

LightCraft is one of the Crafting Apps: free, open-source creative tools from the ArtCraft team, each written from scratch in Rust and each able to stand on its own.

And ArtCraft itself, our AI image and video studio for artists who want real control.

Come make things with us

Our Discord is where artists of every kind hang out: people who paint, shoot, draw, cut film, set type, and people still figuring out what they like to make. Share what you're working on, ask for help, tell us what's broken, or tell us what you wish these tools could do. Whatever your medium and however long you've been at it, you're welcome here.

discord.gg/artcraft · getartcraft.com · The Crafting Apps · LightCraft

License and credits

LightCraft is licensed under MIT OR Apache-2.0.

Showcase photographs are public-domain works, used via Wikimedia Commons: Ansel Adams, The Tetons and the Snake River (1942, U.S. National Archives); Dorothea Lange, Migrant Mother (1936, Library of Congress); Bill Anders / NASA, Earthrise (1968); NASA, The Blue Marble (1972). The demo library is procedurally generated by LightCraft. UI font: Inter (SIL OFL). All icons are original. See assets/ATTRIBUTION.md.

_{Adobe, Photoshop, Illustrator, Premiere Pro, Lightroom, Acrobat, After Effects and InDesign are trademarks or registered trademarks of Adobe Inc. in the United States and/or other countries. LightCraft is an independent, open-source project and is not affiliated with, sponsored by or endorsed by Adobe Inc.; these names are used only to describe the workflows it is compatible with.}

_{Made by the ArtCraft team and community.}