Negs

Your photos, developed on film.

Negs is a free photo app for your browser, Mac, Windows and Linux that runs your pictures through a physical simulation of film: the dyes, the print paper, the glow around highlights, the grain. They come out looking shot on film, not filtered to look like it.

Negs is built on two open-source projects: Andrea Volpato's spektrafilm, the spectral film simulation behind every stock, and turbasvin's spektrafilm-rs, the Rust port that runs it on the GPU. Negs improves on both: the GPU engine now matches the 64-bit reference render closely enough that exports run on the GPU by default, several times faster. It also adds Apple's RAW decoder and lab-style borders, and wraps it all in a web app and native apps for macOS, Windows and Linux.

[!TIP] Film simulation that keeps up with you. Every slider updates live. Faster than spektrafilm-rs; dramatically faster than Python spektrafilm.

▶ Try it in your browser · nothing to install · your photos stay on your device

Download for Mac · macOS 14 or later · Apple silicon and Intel · install steps

Download for Windows · Windows x64 · portable version · install steps

Linux · x86_64 · Flatpak · AppImage · Arch and Omarchy · install steps

getnegs.com

RAW · Apple default	Negs · Kodak Ektar 100

A darkroom in a window

In your browser, or as a native app on Mac, Windows and Linux. Pick a film, pick a paper, drag a slider, and watch the picture change as you move.

• Opens RAW files from most cameras, including Nikon HE★ (Mac only) and 60 MP medium format, plus JPEG, TIFF and PNG
• Reads JPEG, PNG and TIFF colour profiles and previews in the chosen export colour space
• Save, apply and share film and Lab presets, including Python spektrafilm community presets
• Crop, straighten, and add borders with each stock's real edge print
• Image Size enlarges a photo before the film, so grain and halation form at print size instead of being stretched afterwards
• Undo, keyboard shortcuts, pinch to zoom: it feels at home on Mac, Windows and Linux
• Exports PNG, TIFF or JPEG and keeps your camera's EXIF, at 8 or 16 bits per channel (JPEG with a quality slider), in sRGB, Display P3, Adobe RGB or ProPhoto RGB (16-bit only) with an embedded ICC profile
• Export the current film and paper colors as a 33³ sRGB .cube LUT from File → Export LUT… on every platform. No photograph is needed; spatial effects and Post edits are excluded.
• Live preview while you drag a slider, and what you see in the preview is what you export

https://github.com/user-attachments/assets/6c7997a9-04b6-45d2-9ff9-3b0b937627c9

Chemistry, not a filter

Negs doesn't guess what film looks like. It follows the light through the whole chain (film, enlarger, paper, scanner) using the published data for each stock.

• Colour from the spectrum. Your photo is turned back into light, exposed onto the film's three dye layers, printed onto paper and scanned. Colours shift the way they did on the real stock, because the same thing happens to them.
• Halation. Bright lights bleed a warm red glow, the way light bounces back through real film. Street lamps, sun on chrome, candle flames.
• Grain that lives in the image. Grain is simulated in each dye layer from how dense the film is at that spot. It sits inside the picture instead of being laid on top.
• The developer's bite. Development chemistry sharpens edges and deepens colour where tones meet, giving the crispness film has and digital lacks.
• Paper matters. The print paper changes the look as much as the film does, just like in a real lab.
• Print it, or scan it. Print the negative onto paper for the classic lab look, or skip the paper and scan the film directly.

Why not a LUT?

A LUT looks at each pixel on its own and swaps its colour. Real film doesn't work like that: light spreads through the emulsion, highlights glow, grain follows exposure and neighbouring tones pull on each other. Negs simulates all of it, so the look holds up where LUTs fall apart: skin, neon, deep shadows, bright skies.

Borders

Finish with a solid border or a thin keyline in any width and colour, a black film edge, or the full 35mm frame, sprocket holes and all, printed with the stock's own edge markings.

White border	Keyline	Film edge	35mm frame

This is the beginning of the README. Read the rest at the original. Read the full README ↗