How to make photos look like film

01 · Film versus phone

What is the film look?

Film builds a picture. Light exposes silver halide crystals in three color layers; development turns the exposed ones into clouds of dye; a print or a scanner reads the dye through one curve for the whole frame. Each step leaves its mark, and together they are the film look. A phone camera works the other way round: it measures the light, then finishes a picture area by area.

02 · Tone

One curve, and highlights that never clip

A color negative has a lot of room. On Kodak’s datasheet for Portra 400, the toe ends about 3½ stops under a normal exposure and the straight line runs on with no shoulder to at least 6½ stops over. The print paper then bends the brightest part gently into white. That slow roll-off, on a negative that never clipped, is film’s highlight look.

A phone does it differently. Google’s HDR+ paper describes underexposing, merging frames and tone mapping area by area, and warns that “excessive range compression and saturation produces a flat ‘cartoony’ rendition”. On the phone Clack is tested on, the JPEG lifted sunlit walls by up to about a stop beyond its own overall curve.

03 · Color

Color is dye, not saturation

Film makes color by taking light away. More dye makes a more saturated color and also a darker one: cinematographer Steve Yedlin’s film emulation turned a “garish red” darker and yellower at the same saturation. Digital saturation only adds, so strong colors get brighter. All three dyes meet at the paper’s white and at black, so colors fade toward neutral at both ends, and neon colors lie outside what the dyes can make.

Each film adds its own leaning on top. In Clack’s model of Portra 400 printed on Portra Endura paper, yellows go golden, foliage olive and blues toward teal.

04 · Grain

Film grain: what makes it look real

Grain is not noise laid over the picture. Each speck is a developed crystal, or the dye cloud that formed round one: a spread of sizes, at random, clumped, with no grid. A study of grain rendering found uncorrelated grain “clearly unrealistic” and clumping “an essential visual feature” (Newson et al., 2017).

Size

Measured color-negative grain is about 6.5 µm (one dye cloud) and 15 µm (a cluster). On a 35 mm frame drawn 4,080 pixels wide that is under a pixel: at full size, 35 mm grain is a fine texture, not visible specks.

Strength

Strongest in the light midtones; the print squeezes it out into white.

Coarseness

Coarser in the shadows, which only the film’s fastest, largest crystals recorded.

Color

Barely any. Each dye layer grains on its own, blue the coarsest, which shows as a faint yellow-blue mottle, never as pixel-sized color speckle. That speckle is sensor noise.

Speed

Underexposure and push processing bring more grain (Kodak’s Tri-X datasheet), and faster films are grainier (the table below).

How much grain shows depends on the film and the enlargement. Kodak’s Print Grain Index puts 25 at the threshold of visibility, and 4 points is a just-noticeable difference:

What gives fake grain away: a grid, one grain size, the same strength everywhere, colored per-pixel speckle, and in video, grain frozen while the picture moves.

05 · Halation

Halation: the red glow round lights

Light goes through the film, reflects off the back and comes back into the bottom, red-sensitive layer: a red halo round bright lights, orange right beside a strong one, where it reaches the green layer too. The anti-halation backing is not perfectly black, so every color film has a faint halo, seen mostly against dark. CineStill 800T is Kodak’s Vision3 500T cinema film with that backing removed, hence its strong red rims round street lights.

06 · The print

The print, or the scan

The last step sets the look as much as the film. A print paper fixes contrast and saturation together: Kodak ranks its Endura papers Portra (lowest contrast, moderate saturation), then Supra, then Ultra. A black and white print is made on a paper grade, from 0 (soft) to 5 (hard). A slide has no print at all: the film is the picture.

Many film photos online are negatives scanned at a lab: softer contrast, open shadows, pastel color. That is where “overexposed Portra looks pastel” comes from. Portra 400’s curve has no shoulder for six stops, so in Clack’s model of it a frame rated at 200 and printed back comes out almost the same as at 400, with finer grain.

07 · Phone cameras

Why phone photos don’t look like film

A phone camera finishes the picture for you. It merges frames, tone maps area by area, removes noise, sharpens, adds an S-curve and shifts skies and foliage by hue (all named in the HDR+ paper). What is left is smooth, and has no texture of its own for a film look to build on.

08 · Editing

How to edit photos to look like film

In Lightroom or any editor with a tone curve and color controls, in the order film itself works:

1. Start from RAW. A RAW file (DNG) holds the sensor’s data before the phone’s tone mapping, noise reduction and sharpening. Edit a JPEG and all three stay in the picture.
2. Keep the tone global. One curve for the whole frame. Go easy on the tools that lift shadows or hold back skies area by area (in Lightroom: Shadows, Clarity, Dehaze, masks).
3. Shape the curve like film. A toe that lets the blacks go deep without crushing them, a steady middle, and highlights that bend into white over the last stop or two instead of clipping.
4. Make color behave like dye. Rather than raising saturation, darken the strongest colors (luminance down on those hues) and let colors fade toward neutral in the brightest parts.
5. Add fine grain. Sized for the full image, strongest in the light midtones, none in pure white, and colorless or nearly so. Check it at 100 %: no grid, no blotches.
6. Add halation, if you want it. A faint red-orange glow round bright lights against dark. Make it strong only for a CineStill look.
7. Soften the sharpening. Film’s edge boost is broad and gentle. A one-pixel halo reads as digital.
8. Keep one look for a set. A roll has one film, so a set of photos in one look reads as a roll.

Where editing falls short

From a phone JPEG, the phone’s processing stays in the picture: no edit puts back the texture noise reduction took away. You see the look only afterwards, so you cannot expose or frame for it. And it is work for every photo.

09 · Shooting

Why shoot the look instead

Choosing the look before you press changes how you shoot. You see where the highlights roll off and where the shadows go, and expose for that, as you would on a roll of film. And a camera app can ask the phone for a flat frame before the phone finishes it, which an editor only gets from RAW.

* On Android phones whose camera accepts a tone curve of its own. On others, Clack’s films run on the phone’s own frame.

10 · Clack

How Clack does it

Clack is a film camera app for Android and iPhone. You pick a film and shoot; the finder shows the film live, and the saved JPEG has the same look.

Four films, from their data

Kodak Portra 400, Fujifilm Superia X-TRA 400, Kodak Kodachrome 64 and Kodak Tri-X 400, each modeled on the film’s published curves and dyes. Portra prints on Kodak’s Endura papers, Superia on Fujifilm Crystal Archive, Tri-X on a paper grade; Kodachrome is a slide.

A flat frame first

On Android, where the phone’s camera accepts a tone curve of its own, Clack asks for a straight one, which also turns off the phone’s area-by-area tone mapping and color enhancement, and film stills ask for no sharpening and no noise reduction. The film’s curve does the tone.

In film’s order

Halation and grain go in before the film’s curve, which shapes them as a print does. Grain is sized like 35 mm film’s on a 12 MP still and grows with the ISO the light needed, as film shot in a dim room and pushed.

A lab slip

Rate the film over or under, put a filter on the lens, push or pull it in development, choose the paper, print lighter or darker, or take the anti-halation layer off.

One exposure

No frame merging, no scene AI, no face retouching. A DNG beside each JPEG if your phone writes RAW.

Android · iPhoneComing soon to Google Play and the App Store. More about Clack