Free Online Film Negative to Positive Converter — nomorevibe
F
Free Online Film Negative to Positive Converter
Convert scanned film negatives to positives in your browser. Free, no uploads, supports RAW (NEF, CR2, ARW, DNG, RW2) plus 16-bit PNG and iPhone ProRaw, with Kodak/Fuji/Ilford film presets.
AI drew your research figure. Tavotto makes it publication-ready: edit matplotlib figures on a canvas, lay out in mm, check journal rules. Free, open source.
Doop is an open-source multiplayer design canvas and design MCP for Claude Code, Codex, and any AI agent. Design side by side with agents — free in beta.
Negative Converter helps film photographers turn scanned or camera-digitized film into clean, natural-looking positives with a workflow made for everyday editing. It brings frame cleanup, film-aware conversion, roll consistency, finishing controls, and export into one focused workspace.
Whether you are reviewing a fresh roll, restoring family negatives, or preparing a consistent set for sharing, the app is designed to make film conversion feel fast, approachable, and dependable while keeping your photos private.
Simpler local workflow
HEIC import, automatic same-stock roll analysis, local semantic colour anchors,
learned defaults, review filtering and consistent colour-profile export are
available in the local workflow. CMYD remains a primary control above basic
adjustments; Advanced reveals the optional tools. Desktop folder watching is
optional. See the automation design,
workflow guide and
validation and remaining acceptance.
🌟 Features
📷 Supports HEIC/HEIF, PNG/JPG file uploads (including 16-bit PNGs via UPNG.js and .cr2, .nef, .arw, .dng, .raw, .rw2 raw files via LibRaw-Wasm)
🔄 Rotation correction via slider or number input
✂️ Visual cropping with drag-and-drop overlay and a film-format ratio lock (135, 120, 4×5/8×10, 5×7)
⚖️ One-click white balance by clicking a gray area in the image
🎛️ Live controls for:
Temperature & Tint
Vibrance & Saturation
Cyan / Magenta / Yellow (CMY) channels
🎞️ Film presets for color negative, B&W negative, and positive slide stocks across Kodak / Fujifilm / Ilford
🔍 Film edge reader: whole-strip scans that show the perforations get their DX edge barcode decoded (ISO 1007), the stock named from The Big Film Database, a matching preset suggested and the film base sampled from the unexposed rebate (see docs/film-edge-reader.md)
🎞️ Roll analysis: analyse the selected frames together like a minilab — one film base and one tone analysis for the roll, a per-frame exposure offset, and frames that do not belong flagged as outliers (see docs/roll-analysis.md)
🗂️ Light table: grow the film strip into a thumbnail grid of the whole roll with stock and outlier badges, RAW thumbnails and keyboard navigation (see docs/light-table.md)
🔬 Darkroom paradigm: a test strip of patches along one axis (click to apply), enlarger controls with CMY filtration, exposure in stops and multigrade paper grades, a dodge & burn brush applied in linear light before the curves and at full resolution on export, and paper emulation for RA-4 and B&W papers with toning (see docs/darkroom.md)
📷 Camera scanning: a flat field from a blank light-pad frame removes the pad's falloff before inversion, a lab scan of the same frame is aligned and its look fitted as a colour matrix plus curves, 2–5 shots of one frame merge as a noise-averaged or HDR 16-bit file, and a live loupe converts the camera feed through the current recipe and captures into the photo list (see docs/camera-scanning.md)
🗃️ The roll's home: film stock, ISO, camera, lens, lab and frame numbers written into EXIF/XMP (AnalogExif schema) on every export, a printable 300 dpi contact sheet with sprockets and frame numbers, a project file that saves and reopens the whole roll (with an IndexedDB recovery copy), and shareable conversion recipes as short codes or QR (see docs/roll-home.md)
🔬 Technical depth: the Step-3 adjustments run at 16 bits on export so 16-bit PNG/TIFF carry real 16-bit data, a linear DNG export (inverted, film-base normalised, no tone curve) for Lightroom / Capture One, and on-device AI dust repair with bundled MI-GAN over the mask's tiles, falling back to TELEA (see docs/technical-depth.md)
🧪 Expired film rescue: a separate entry and flow for aged rolls, negatives and positives alike — fog, overall cast, shadow/highlight crossover and lost speed are measured on the positive and corrected by density (a colour table over luminance plus one shared tone curve), and OpenCV.js measures what varies across the frame (uneven fog surface, local contrast), with a diagnosis and seven strengths on the preview, the 16-bit export and batch exports (see docs/expired-film-rescue.md)
🗂️ Data-driven preset system defined in negative2positive/src/silvercore/engine/FilmPresets.js (supports alias fallback for older preset IDs)
🔍 Optional lens profile workflow: search/select Lensfun profiles manually, or skip lens correction and continue
🧷 Roll-level lens settings: lens correction on/off and parameters can be applied to selected files or reused via roll reference
🛡️ Privacy-friendly: all image processing happens locally in your browser
💾 Flexible export: PNG / JPEG / TIFF with selectable bit depth (8-bit, plus 16-bit for PNG/TIFF)
🚀 How to Use
Workflow (Step 1 → 3)
Step 1: Crop
Rotate / Auto Frame / Crop until only the film area remains
Click Next: Film Settings (negatives) or Next: Positive Mode (slides)
Step 2: Film Settings
Pick film type: Color, B&W, or Positive
Color negatives: set the mask baseline (sample manually / auto-detect / roll reference)
Click Next: Convert and Continue
Step 3: Adjust & Export
White balance + sliders + curves to taste
Export PNG / JPEG / TIFF
Film type quickstart
Color negative: Step 1 → Next: Film Settings → keep Color → set mask → Next: Convert and Continue → Step 3
B&W negative: Step 1 → Next: Film Settings → select B&W → Next: Convert and Continue (no mask) → Step 3
This repo includes a Tauri wrapper to package the web app as an offline desktop application for Windows / macOS / Linux.
Development
npm ci
npm run dev:web
Vercel deployment (important)
This app must be deployed from the Vite build output, not by serving source files directly.
Required settings (as recorded in .vercel/project.json):
Root Directory: negative2positive
Install Command: npm ci
Build Command: npm run build:web
Output Directory: negative2positive/dist
npm run build:web generates negative2positive/dist (for local/Tauri) and also syncs it to root dist.
Because the Root Directory is negative2positive, Vercel reads negative2positive/vercel.json (cache and security headers); the repository-root vercel.json is not applied to the deployment.
If Vercel serves negative2positive/index.html directly, module imports like pako / utif / jszip will not resolve in browser and upload buttons can stop working.
Feedback endpoint
The header Feedback button posts to negative2positive/api/feedback.mjs (a Vercel serverless function) at /api/feedback/; the desktop app uses https://negative-converter.tokugai.com/api/feedback/. Keep the trailing slash: with trailingSlash: true Vercel answers /api/feedback with a 308, and the desktop app's cross-origin preflight fails on a redirect. The Vercel project's Root Directory is negative2positive, so functions MUST live under negative2positive/api/ — an api/ directory at the repository root is silently ignored. The function files the message as a GitHub issue labeled feedback. Configure in Vercel → Project → Settings → Environment Variables:
FEEDBACK_GITHUB_TOKEN (required): fine-grained personal access token with Issues: Read and write and Contents: Read and write on the target repo. Contents is what lets attached screenshots be uploaded to the orphan feedback-assets branch, which must already exist — without it the issue is still filed but the images are silently dropped. Without the token entirely the endpoint returns 503 and the form shows the error state.
FEEDBACK_GITHUB_REPO (optional): owner/repo to file issues in; defaults to lexluthor0304/NegativeConverter.
The endpoint allows cross-origin calls only from the production domain, Tauri desktop webviews, and localhost dev servers.
Desktop dev (Tauri)
npm run tauri:dev
Build installers
npm run tauri:build
Build outputs are placed under:
src-tauri/target/release/bundle/
macOS installation troubleshooting
If macOS shows "Negative Converter is damaged and can't be opened", this is because the app is not yet notarized by Apple. Use one of these methods:
Method 1 — Terminal command (recommended):
xattr -cr /Applications/Negative\ Converter.app
Method 2 — Right-click open:
Right-click (or Control-click) the app → select Open → click Open in the confirmation dialog.
Method 3 — System Settings:
Go to System Settings → Privacy & Security, scroll down and click Open Anyway next to the blocked app message.
Linux AppImage troubleshooting
Run AppImage directly, not with sudo.
The desktop app now applies AppImage-only runtime guards:
isolates GIO module loading to avoid host gvfs/GLib ABI mismatches
standard AppImage keeps DMABUF when render nodes are usable, and auto-falls back when not
compatibility AppImage (*_legacy-glibc235.AppImage) defaults DMABUF off for startup stability
Optional override for DMABUF behavior:
force enable: NEGATIVE_CONVERTER_DMABUF=on ./Negative\ Converter*.AppImage
force disable: NEGATIVE_CONVERTER_DMABUF=off ./Negative\ Converter*.AppImage
shared-memory transport: NEGATIVE_CONVERTER_DMABUF=shm ./Negative\ Converter*.AppImage
sets WEBKIT_DMABUF_RENDERER_FORCE_SHM=1. WebKit keeps accelerated compositing and copies each
frame through shared memory, instead of painting the whole page in software as off does.
It is not yet the legacy default: that needs the startup matrix below.
a WEBKIT_DISABLE_DMABUF_RENDERER or WEBKIT_DMABUF_RENDERER_FORCE_SHM you set yourself always wins.
The terminal log shows the decision ([linux-compat] lines) and, once a photo is open, one [webview]
line with the WebGL renderer, the decision, the WebKitGTK version and the starting preview tier.
Include both in bug reports about sluggish sliders.
One [memory] line at startup shows the WebKitGTK memory limit the app applies before the window
opens (half of RAM, so WebKit's 30 s cache and JIT purge starts at a quarter of RAM instead of
1.5 GiB), or WebKit defaults when /proc/meminfo could not be read.
When the webview composites in software (the legacy default, off, no render node) or WebGL is a
software rasteriser (llvmpipe, SwiftShader), slider and curve drags preview at up to 1 MP and the
full display resolution returns on release. Other hosts drop to that tier only when frames run slow.
NEGATIVE_CONVERTER_FRAME_LOG=1 logs every drag's frame intervals and canvas size as [webview] lines.
Startup matrix for making shm the legacy default (Ubuntu 22.04 and Debian 12; Intel, AMD, NVIDIA
proprietary; X11 and Wayland; each must start without a blank window or crash and create a WebGL
context): not run yet.
If startup still fails on older distros, use the compatibility AppImage (*_legacy-glibc235.AppImage).
Release (GitHub Actions)
Update versions:
src-tauri/tauri.conf.json
src-tauri/Cargo.toml
Merge to main
GitHub Actions automatically:
creates a vX.Y.Z tag
publishes a GitHub Release with the installers
(optional) syncs installers to Cloudflare R2 under negative-converter/release/vX.Y.Z/
Cloudflare R2 sync (optional)
If you want the release workflow to upload installers to R2, add one of these GitHub Actions secret sets:
Feel free to fork, open issues, or submit pull requests with ideas or improvements.
This tool is designed to be simple, fast, and modifiable.
📄 License
MIT License
🙏 Acknowledgments
Special thanks to LibRaw-Wasm by ybouane,
which made it possible to support various raw image formats such as .cr2, .nef, .arw, .dng, .raw, and .rw2 directly in the browser via WebAssembly.
Your work was an essential reference and greatly accelerated development.
HEIC/HEIF decoding uses the browser when supported, then the bundled libheif WASM decoder in a worker. See negative2positive/public/codecs/README.md for licence and replacement instructions.
The desktop app can decode RAW files with LibRaw 0.22.1 linked natively (used under CDDL-1.0; source in src-tauri/vendor/libraw, notices in negative2positive/public/licenses/raw-decoder-notices.txt). See docs/native-raw-decode.md.
