Latent

Open-source camera-backed look lab for Fujifilm photographers. Latent lets you keep a local recipe library, read and restore camera custom slots, render RAF files through the camera processor, and iterate on a look with the real Fujifilm pipeline instead of a browser approximation.

Latent is an independent fork and product expansion inspired by FilmKit. FilmKit proved that a browser can manage Fujifilm presets and render RAF files through the camera over WebUSB; Latent builds from that idea toward a broader open-source workspace for recipe libraries, camera backups, connection reliability, model capability tracking, and contributor-friendly protocol packages.

Status: pre-launch, hardware-backed alpha. Core packages, WebUSB connection stability, recipe import/export, camera slot read/write, and RAF preview are implemented. See ROADMAP.md and PROGRESS.md.

Italian: see README.it.md.

Latent is for Fujifilm camera owners. It is not affiliated with or endorsed by Fujifilm Holdings Corporation. "Eterna", "Velvia", "Provia", "Acros", "Classic Chrome" and other simulation names referenced in recipes are trademarks of their respective owners.

What Latent Does Today

• Recipe library: browse, search, import, export, delete, restore factory defaults, and keep everything local in the browser.
• Recipe creator: start from photographic intents, duplicate an existing look, edit schema-backed Fujifilm settings, and export a validated JSON recipe without connecting hardware.
• Camera connection: connect over WebUSB in Chromium browsers, recover from refresh/unplug/camera sleep, and surface macOS claim-collision guidance.
• Custom slots: read camera-side C1-C4 recipes, import them into the library, and write verified recipe fields back to a chosen slot.
• RAF preview: send a local RAF file to the connected camera, render the selected recipe through the camera image processor, and diagnose parameter groups when a look does not match expectation.
• Schema and protocol packages: use MIT-licensed packages for recipe validation, capability-aware translation, PTP framing, WebUSB transport, and connection state management.

Screenshots

Library workspace	RAF preview

Recipe creator, dark	Recipe creator, light

Mobile creator

Why It Exists

Most recipe tools are static forms: you copy settings by hand and hope the camera produces the expected result. Latent treats the camera as the rendering engine. The goal is a workflow where a photographer can:

1. Back up the custom slots already on the camera.
2. Import or design recipes locally.
3. Preview a recipe against a known RAF using the camera processor.
4. Write a verified recipe to a disposable slot.
5. Restore the original slot if the experiment is not right.

Relationship To FilmKit

Latent is not meant to compete with FilmKit. It exists because FilmKit's WebUSB/PTP work made the path credible, and because there is room for a community project with a different emphasis.

What differs today:

• Workflow safety: Latent makes backup, read-back, restore, and explicit slot writes first-class flows.
• Connection reliability: Latent adds a dedicated connection manager, structured error classification, reconnect behavior, and macOS PTP claim-collision guidance.
• Package boundaries: protocol, WebUSB transport, connection management, and recipe schema live in separate @latent/* packages.
• Schema discipline: recipe fields, camera capabilities, translators, and round-trip tests are kept in lockstep by CI.
• Open-source onboarding: docs, use cases, hardware QA, governance, issue templates, and launch checklist are part of the repo.
• Validation target: current hands-on validation has focused on X-S20 and X-M5, while FilmKit documents X100VI as its primary tested body.

Where Latent should go next:

• richer recipe editing with auto-render, closer to FilmKit's fast creative loop;
• broader camera compatibility reports from the community;
• safer verified writes for more camera-specific fields;
• a public library workflow for importing, comparing, and sharing recipes;
• eventually, native transport support when WebUSB becomes the limiting factor.

Quick Start

nvm use                   # Node 22, pinned by the repo
npm install
npm run validate          # typecheck + lint + tests + license + lockstep
cd apps/web
npm run dev               # Vite at http://localhost:5173

Open http://localhost:5173 in Chrome, Edge, or Arc. WebUSB works only on localhost or HTTPS. The recipe library works without hardware; camera flows need a Fujifilm body set to USB/PTP mode.

Hardware Notes

Development has been exercised with Fujifilm X-S20 and X-M5 bodies. Other recent X-series cameras may work, but should be treated as unverified until someone runs the hardware checklist.

Before writing to a camera:

• Import the existing slot into the library first, so you can restore it.
• Choose a disposable custom slot. Do not overwrite your only copy of an important look.
• Keep the camera awake and connected directly by USB when possible.
• On macOS, close Image Capture, Photos, X RAW Studio, and any app that may claim the PTP interface.

Manual release checks live in docs/qa/hardware-test-plan.md.

Use Cases

Detailed flows live in docs/use-cases.md. The short version:

• Back up my camera recipes: connect, read slots, import each custom slot into the local library, export JSON if needed.
• Try a recipe on a known RAF: open the RAF workspace, select a recipe, render, adjust preview-only controls, and compare diagnostic variants.
• Create a recipe from scratch: open the Creator workspace, choose an intent or duplicate a selected look, tune the Fuji controls, then save the result into the local library or export JSON.
• Write a recipe to camera: select a library recipe, write to C1-C4, then verify by reading the slot back.
• Recover from a bad write: select the previously imported backup recipe and write it back to the same slot.

Repo Map

Path	What it is
apps/web	AGPL web app: library, camera panel, RAF workspace, bilingual EN/IT UI
packages/camera-connection	Connection manager, state machine, classifier, and WebUSB camera driver
packages/recipe-schema	Zod recipe schema, camera capability matrix loader, migrations, diff and translators
packages/ptp-fuji	MIT PTP protocol layer for Fujifilm cameras, forked from filmkit with attribution
packages/ptp-fuji-webusb	WebUSB transport implementing the PTP transport boundary
packages/ai-agent	Future AI helper package; currently a stub
data/	Camera model capability data and bundled seed recipes
docs/	Specs, execution plans, ADRs, use cases, QA, and review transcripts

Development Commands

npm run typecheck
npm run lint
npm run test
npm run license-check
npm run lockstep-check
npm run validate

Adding a recipe field must update schema, camera capabilities, translator, and round-trip tests together. npm run lockstep-check enforces this.

Privacy And Safety

• Recipes and RAF files stay local unless the user explicitly exports or uploads something elsewhere.
• WebUSB access is gated by the browser picker and the app's Fujifilm vendor filter.
• Camera writes require an explicit slot button click.
• Preview-only fields such as exposure compensation and D Range Priority are rendered through the RAF flow but are not written to custom slots until the camera write path is verified.
• Security issues should be reported privately; see SECURITY.md.

Contributing

Start with CONTRIBUTING.md, then read docs/onboarding.md. The roadmap is intentionally narrow because camera write paths need careful hardware validation.

Funding

Latent is open source and has no paid features. If it saves you time or you want to support hardware testing, you can contribute through Buy Me a Coffee.

License

• App (apps/*): AGPL-3.0. If you run a modified Latent app as a network service, publish the corresponding source.
• Libraries (packages/*): MIT. They are designed to be reusable outside this app.

The split is intentional: the community-facing app stays open, while the underlying protocol and schema libraries remain broadly reusable.

Acknowledgements

• filmkit, whose PTP work made packages/ptp-fuji possible
• rawji, fudge, libgphoto2, ISO 15740, and the Fujifilm reverse-engineering community for the protocol trail
• The X-Series photographers testing real bodies, real recipes, and real failure modes
• Formray, the studio Latent is built inside

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Latent. Develop the image you did not know you had.