Guide · Updated
This film filter puts your photo through one of eight films: the films in Clack, a film camera app for Android. Each is modeled from the real film’s published curves, its colors and contrast, then printed the way a lab printed it, with the film’s grain and, on color film, the red glow round lights called halation. Choose a photo above, pick a film and download it. It runs in your browser; nothing is uploaded.
It is the app’s own film, ported to the browser: the same color tables, compiled by the same code, and the same steps in the same order. What differs is where the photo starts, which the third section explains.
01 · Films
The eight films
Each goes by Clack’s name, with the film it is based on beside it. Clack is not affiliated with Kodak, Fujifilm or Ilford.
| Film | Based on | The look | How it is made |
|---|---|---|---|
| Portrait 400 | Kodak Portra 400 | Soft, kind to skin. | Printed on Kodak Portra Endura paper |
| Minilab 400 | Fujifilm Superia X-TRA 400 | The corner minilab: punchy, green shadows. | Printed on Fujifilm Crystal Archive paper |
| Chroma 64 | Kodak Kodachrome 64 | Rich color, deep shadows. | A slide: no print, the film is the picture |
| Golden 200 | Kodak Gold 200 | Warm drugstore prints. | Printed on Kodak Edge paper |
| Vivid 100 | Kodak Ektar 100 | The boldest color, the finest grain. | Printed on Kodak Endura Premier paper |
| Cinema 500T | Kodak Vision3 500T | Movie film for lamplight, red glow round lights. | Printed on Kodak 2383 print film, as in a cinema |
| Press 400 | Ilford HP5 Plus 400 | Black and white, soft with a coarse grain. | Printed on black and white paper |
| Street 400 | Kodak Tri-X 400 | Black and white, hard with a fine grain. | Printed on black and white paper |
Four have pages of their own: Portrait 400, Minilab 400, Chroma 64 and Street 400. For black and white with a yellow, orange, red or green filter on the lens, use the black and white converter; for the look of a digital compact around 2000, the digicam filter. Minilab 400 and Golden 200 behind a disposable’s plastic lens are the disposable camera filter.
02 · The film
What happens to your photo
The steps run in the order film runs them, light first and the print last:
- Back to light. The photo’s sRGB encoding is undone, so each pixel is an amount of light again, which is what film responds to. Then the phone’s own look is undone too. Phones darken shadows and squeeze highlights, and they add color. We measured it across 43 phones from Apple, Google, Samsung and four other makes, each phone’s photo against its own RAW: in a bright scene, about 1.6 stops for each stop of light in the shadows, falling to 0.7 in the highlights, and with that undone, colors still about a fifth stronger than the sensor saw, so the tool takes that back too. Left in, both would sit under the film’s.
- Halation. On color film, light that passes through the film and comes back off its base exposes the red layer again round bright lights: a red-orange glow. Black and white film has none here. Cinema 500T glows most: as a still film it comes with its anti-halation backing removed.
- Grain. Round clumps the size of 35 mm film’s, strongest in the light mid tones and coarser in the shadows. At 1600 px they are fine, as a 35 mm print’s are at that size; the grain tool makes it stronger or larger.
- The print’s exposure. A lab sets the exposure of each print from its negative; here a printer light reads the photo and pulls its average brightness most of the way to a print’s, so a dark photo prints lighter and a bright one darker. Chroma 64 is a slide, with no print: a meter sets its exposure, as a camera’s would have, and slide film’s narrow range shows in deep shadows.
- The film and the paper. The exposure goes through the film’s curves from its datasheet, each color layer on its own, and then through the paper it was printed on. That is where the colors come from: Portra’s soft skin, Superia’s green shadows, Ektar’s saturation.
03 · The difference
A filter on a finished photo, and shooting on film
A phone photo is finished before you see it: the phone has brightened its shadows, compressed its highlights, sharpened it and clipped what was too bright to keep. Any film filter, this one included, starts from that. This one undoes the phone’s tone curve and extra color first, as measured across 43 phones of seven makes. Each phone curves a little differently, and every phone curves a dull scene more than a bright one, so the undoing is close, not exact; highlights the phone clipped stay clipped.
In Clack the film comes first. On phones that allow it, the app has the camera hand over its straight frame, the light as the sensor measured it, and the film is made from that, before the phone’s look is added. That is why the app keeps the highlights a negative holds, and why our guide to making photos look like film says to shoot it rather than edit it. This filter is the same films on a photo you already have.
Clack is a film camera app for Android: eight films, a light meter, and photos made at the camera’s full size. Join the list to hear when it is on Google Play.
Questions
- What is a film filter?
- A filter that makes a digital photo look as if it were shot on film: the film’s colors and contrast, its grain, and on color film the red glow round bright lights called halation. Most app filters are made by eye; the ones here are built from each film’s published curves.
- Which films are in this film filter?
- Eight, as Clack has them: Portrait 400 (based on Kodak Portra 400), Minilab 400 (Fujifilm Superia X-TRA 400), Chroma 64 (Kodak Kodachrome 64), Golden 200 (Kodak Gold 200), Vivid 100 (Kodak Ektar 100), Cinema 500T (Kodak Vision3 500T), and two black and white films, Press 400 (Ilford HP5 Plus 400) and Street 400 (Kodak Tri-X 400).
- Is there a Kodak Portra 400 filter?
- Portrait 400 is Clack’s film based on Kodak Portra 400: modeled from Kodak’s published curves for the film and printed on Portra Endura paper, as a lab printed it. Clack is not made by or affiliated with Kodak.
- Is my photo uploaded?
- No. It is decoded and drawn by your browser, on your device, and the page sends nothing anywhere. Once the page has loaded, the tool works offline.
- Why is the download 1600 px?
- This is the web’s taste of Clack’s films, sized for posting and sharing. The app makes its photos at the camera’s full size.
- Is it the same as shooting with Clack?
- The films are the same, but the start is not. The app gives the film the camera’s straight frame, light before the phone has processed it; a finished photo already has the phone’s contrast, sharpening and clipped highlights in it. The filter undoes the phone’s contrast as measured across 43 phones, but each phone and scene differs a little and clipped highlights stay clipped, so it is close, not the same.
- Is the film filter free?
- Yes. No sign-up and no watermark; the photos you make are yours.
Sources
- Kodak Portra 400, technical data E-4050
- Kodak Portra and Supra Endura papers (E-4021)
- Fujifilm Superia X-TRA 400, data sheet AF3-0217E
- Fujifilm Crystal Archive Type CA paper
- Kodak Kodachrome 64 and 200, technical data E-88
- Kodak Gold 200, technical data E-7022
- Kodak Ektar 100, technical data E-4046
- Kodak Vision3 500T, technical data H-1-5219
- Ilford HP5 Plus, technical information
- Kodak Tri-X 320 and 400, technical data F-4017
- spektrafilm, digitized film data (CC BY-SA 4.0)
The films are Clack’s film model, compiled from these data sheets (and spektrafilm’s digitized curves) by the app’s own code; the filter is its shader, ported to WebGL2.