What does pushing film mean?

Rating a film faster than its box speed, so it is underexposed, and developing it longer to make up the density. An ISO 400 film shot at 800 and developed for it is pushed one stop; at 1600, two stops. Pulling is the reverse: rated slower, developed shorter.

Does pushing film make it faster?

Less than the rating says. Kodak puts the real speed gained on its color motion picture negatives at under a third of a stop for push 1 and about half a stop for push 2, and says push processing “is not recommended as a means to increase photographic speed”. A push brings back the mid tones’ density and adds contrast; the shadow detail the film did not record stays lost.

Does pushing film increase grain?

Yes. Kodak says a push brings “an increase in contrast and graininess” on Tri-X, and “increased granularity” on its color negatives. Pulling a color negative does the reverse: Kodak calls it “a noticeable improvement in granularity”.

How many stops can you push film?

Black and white goes furthest: Kodak gives times for Tri-X 400 at EI 3200, three stops, and Ilford says HP5 Plus gives “good results” to EI 3200. Kodak publishes two-stop pushes for Portra 800. Fujifilm allows Velvia 100 one stop with little change and two “depending on the scene”. Kodak did not recommend pushing Kodachrome 64 at all.

Can you push Portra 400?

Labs push it, but Kodak publishes no push data for Portra 400; its push times and curves are for Portra 800. A push of a color negative mostly adds contrast and grain. For low light a faster film is the better answer.

Should I push 400 film to 800?

Often there is no need. Kodak says Tri-X can be underexposed by one stop and developed normally, with “a slight loss in shadow detail”, and color negatives have latitude on the underexposed side too (Kodak gives Gold 200 two stops). A one-stop push mostly adds contrast.

When should you pull film?

When a roll was overexposed by a stop or more, or to soften a contrasty scene. Kodak gives a pull time for its motion picture negatives, but none for C-41 still films, and color negatives hold overexposure well without one: Portra 400 rated at 200 and printed normally comes out almost as it does at box speed.

Can you push only some frames on a roll?

No. Development is one time for the whole roll, so every frame gets the same push. Shoot the roll at one rating, or cut the film in the dark and develop the pieces apart.

Clack has no film to develop: it is a camera app that runs film models on a phone’s photo. Its Contrast control has four steps, Soft, Normal, Hard and Harder, which are each film’s development pulled one stop, normal, pushed one and pushed two, with the grain coming with them.

Guide · Updated 5 November 2026

Pushing film

Push and pull processing, film by film.

Pushing film is rating it faster than its box speed, so every frame is underexposed, then developing it longer to make up the density. An ISO 400 film shot at 800 is pushed one stop; at 1600, two stops. It buys a faster shutter in low light, at a price: more contrast, more grain, and shadows that development cannot bring back, since the film never recorded them. Pulling is the reverse: rated slower, so overexposed, and developed for less time, for lower contrast and, on color negative, finer grain. Either way the whole roll is developed together, so the whole roll is pushed or pulled.

Below: the speeds for each push, what a push does to the negative and the print, color film against black and white, pulling, how far each film goes by its maker’s data, how to push a roll, the pushed look on a digital camera or a phone, and the push in Clack.

01 · The idea

What is push processing

A film’s box speed, its ISO, assumes the maker’s normal development. Rate it faster and it gets less light; develop it longer and the developer builds more density, so the negative is printable again. The speed you rate it at is the exposure index, EI, and each stop doubles it. Development changes the film’s curve, how much density each step of light makes, not how much light the film caught.

Box speed	Pull one	Push one	Push two	Push three
ISO 100	50	200	400	800
ISO 200	100	400	800	1600
ISO 400	200	800	1600	3200
ISO 800	400	1600	3200	6400

Each stop is twice the speed or half of it (our arithmetic).

02 · The cost

What pushing film does

Kodak, on Tri-X 400 (F-4017): “Because of these films’ exposure latitude, you can underexpose by one stop and use normal processing times. Prints will show a slight loss in shadow detail.” Two stops under needs a push, and prints show “an increase in contrast and graininess with further loss of shadow detail”. The curve shows why. Longer development adds the most density where the film got the most light, and almost none in the toe, where the shadows are.

Kodak Tri-X 400 as Clack’s engine holds it: density on the negative (base and fog included) against exposure, 0 at the meter’s mid gray. Normal is the curve read off Kodak’s chart for T-MAX developer; pushed two adds the density Kodak’s curves gain at its EI 1600 time. In the toe, four stops under gray, the push adds 0.08 of density; two stops over, 0.42 (our arithmetic on the engine’s data). Longer development builds the parts of the negative that got light, not the parts that got almost none.

So a push brings the mid tones and highlights back up and makes the print harder, but the deep shadows of an underexposed frame stay thin. Printed back to the same mid gray, as a printer would:

-4-3-2-10+1+2+3+4+5

Box speed, 400

Rated 800, normal

Rated 1600, normal

Rated 1600, pushed two

Clack’s model of Kodak Tri-X 400 on grade 3 paper, a gray card from four stops under to five over the meter’s mid gray, each printed back to the same mid gray. Rated 800 and developed normally prints almost as box speed, as Kodak says. Rated 1600 with no push, the shadows go flat and gray. Pushed two, the blacks are black again and the light tones brighter, but the three darkest steps sit closer together than at box speed. The engine’s output, before grain.

	Push	Pull
Rated	Faster than box speed: the film is underexposed	Slower than box speed: the film is overexposed
Developed	Longer	Shorter
Contrast	Higher	Lower
Grain	More (Kodak: “increased granularity is also a by-product”)	Finer on color negative (Kodak: “a noticeable improvement in granularity”)
Shadows	Thin: detail the film never recorded stays lost	Open, with detail
Highlights	Brighter, reaching white sooner	Softer, further from white
What it is for	Low light, a faster shutter, or the hard, grainy look	A roll that was overexposed, or a contrasty scene

Kodak’s words from F-4017 and its page on pushing and pulling its color motion picture negatives; the shadows and highlights rows are the wedges on this page.

Grain grows with a push twice over: the film got less light, and the steeper curve makes the print’s grain stronger. Why less light means coarser grain is in what is film grain.

03 · Color

Pushing color film

A color negative has three layers, and a push does not build them alike. Kodak, on its motion picture color negatives: pushing gives “typically higher contrast images with a color bias and reduced photographic speed”; contrast builds most in the bottom, cyan and magenta, layers, which “produces yellow highlights and blue shadows in the print when mid-scale neutrals are balanced”. The speed it gains is small: “Push 1 processing produces ER speed increases of less than a 1/3 of a stop”, push 2 “around 1/2 of a stop”, and “the end result is smoky shadows in prints”. Kodak’s advice: “Push processing is not recommended as a means to increase photographic speed.”

Among still films, Kodak publishes push curves for Portra 800, to EI 1600 and 3200, and none for Portra 400, Gold 200 or Ektar 100; Fujifilm gives none for Superia X-TRA 400. Labs push them all the same, on Kodak’s C-41 push times.

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Box speed, 400

Rated 1600, normal

Rated 1600, pushed two

Rated 200, pulled one

Clack’s model of Kodak Portra 400, the same gray card, each printed back to the same mid gray. Rated 1600 with no push, the blacks lift and go gray. Pushed two, they are dark again, a touch blue, with the highlights a touch yellow, as Kodak describes; the darkest steps run together. Rated 200 and pulled one, the shadows open and the highlights soften. Every row but box speed is an estimate: each layer gains the density Kodak’s Portra 800 gains from the same push, or loses it for the pull, since Kodak gives no curve for Portra 400 pushed or for any C-41 pull. The engine’s output, before grain.

A slide has no print to correct it, so a push is the lab’s only lever. Fujifilm says Velvia 100 shows “minimum variation in color and gradation during push/pull processing over a range from –1/2 to +1 stop”, and allows up to two stops “depending on the scene”. Kodak’s datasheet for Kodachrome 64: “We do not recommend push processing of KODACHROME 64.”

04 · Pull

What is pull processing

Pulling is rating a film slower than box speed, an ISO 400 film at 200, and developing it for less time. Kodak calls it “compensation for over exposure … by underdevelopment”, and on its motion picture negatives it “produces a noticeable improvement in granularity, a reduction in overall contrast … with no perceptible change in sharpness”. Photographers also pull to tame a scene with more contrast than the film holds.

A color negative often needs no pull: overexposure is where its latitude is. Kodak gives Gold 200 “wide exposure latitude—from two stops underexposure to three stops overexposure”, and Clack’s model of Portra 400, rated 200 and printed back, comes out almost as at box speed with finer grain (the gray scales on the Portra 400 page). Kodak publishes no pull time for its C-41 still films, and Ilford none for HP5 Plus in its HC developer.

05 · By film

How far can you push film

Black and white goes furthest, and its developer is in your hands: Kodak gives times for Tri-X 400 to EI 3200, three stops. Color negative is pushed a stop or two, mostly for contrast. Slide film, by Velvia’s sheet, takes a stop with little change. What each film’s maker publishes:

Film	The maker’s push and pull data	Clack’s Contrast steps
Kodak Tri-X 400	EI 800 develops normally. Push times for EI 1600 and 3200: in D-76, 9½ and 11 min against 6¾. No pull	Harder is Kodak’s EI 1600 time; Hard and Soft are estimates
Ilford HP5 Plus 400	“Good results” from EI 400 to 3200. In Ilford HC (1+31), 9½ min for EI 800 and 14 for EI 1600 against 6½. No pull in HC	Hard and Harder are Ilford’s times; Soft is an estimate
Kodak Portra 400	None. Kodak’s push data is for Portra 800: EI 1600 and 3200, C-41 developer 3 min 45 s and 4 min 15 s against 3 min 15 s	Portra 800’s push data, an estimate
Fujifilm Superia X-TRA 400	None on its sheet	Portra 800’s push data, an estimate
Kodak Gold 200	None. Its sheet gives latitude instead: “from two stops underexposure to three stops overexposure”	Portra 800’s push data, an estimate
Kodak Ektar 100	None, and no latitude statement	Portra 800’s push data, an estimate
Kodak Vision3 500T	Kodak’s push and pull times for its motion picture negatives (ECN-2): push 1 3 min 40 s, push 2 4 min 40 s, pull 1 2 min 30 s, against 3 min. No pushed curves	Portra 800’s push data, an estimate
Kodak Kodachrome 64	“We do not recommend push processing of KODACHROME 64.” Only Kodachrome 200 was pushed	An estimate
Fujifilm Velvia 100	“Minimum variation in color and gradation” from −½ to +1 stop; up to +2 “depending on the scene”. No pushed curves	Not one of Clack’s films

From each film’s datasheet (Sources). Times are for a small tank at 20 °C for black and white, and the standard process for color. Clack’s column is where its Contrast steps on the film based on it come from (below); an estimate is our model, not the maker’s.

06 · How

How to push a roll of film

Decide before the roll. Development is the same for every frame on the roll, so the whole roll is pushed or pulled together.
Set the rating. Set the camera or the meter to the speed you rate the film at: 1600 for an ISO 400 film pushed two stops, 200 for one pulled one.
Shoot every frame at that rating. Meter as usual at the new speed. Do not mix ratings on one roll.
Mark the roll. Write the push on the canister or the cassette’s tab, “push 2” or “EI 1600”, so the roll is not developed normally by mistake.
Develop for the rating. Tell the lab how many stops, or develop it yourself for the maker’s time: Tri-X 400 at EI 1600 is 9½ minutes in D-76 at 20 °C, against 6¾ at box speed.

Kodak calls the push and pull times for its motion picture negatives “starting positions for any laboratory”. Metering without a meter at any rating: the sunny 16 calculator.

07 · Digital

Pushing on a digital camera or a phone

Raising the ISO on a digital camera or a phone is the nearest thing to a push: less light, the signal amplified, more noise. It does not change the tone curve the way longer development does, and digital noise is not grain. The pushed look is an edit on top: a harder curve with the deepest shadows black, the light tones brighter, and coarser grain. The steps for a film look in any editor are in how to make photos look like film; the film grain overlay makes the grain.

08 · Clack

The push in Clack

Clack is a film camera app for Android, with eight films modeled on real ones. On each, Contrast is one of the two dials on a recipe, and a control in the recipe editor: Soft, Normal, Hard and Harder are the film’s development pulled one stop, normal, pushed one and pushed two, on that film’s own curves. Where the maker publishes the push, Clack uses it: Harder on Street 400 (based on Kodak Tri-X 400) is Kodak’s EI 1600 time, Hard and Harder on Press 400 (based on Ilford HP5 Plus 400) are Ilford’s. On the color films each step is the estimate in the table above.

Pushed, not rated. Clack exposes for the meter. Hard and Harder develop the negative longer at that exposure, so they add a push’s contrast and grain without darkening the frame.
The grain comes with it. A step harder coarsens the grain, as a push does; the grain also grows with the ISO the phone needed, about 15 % a stop above ISO 100, as film shot in a dim room.
Two recipes ship pushed. Available light, Press 400 on Harder with a coarse grain, for dim rooms with no flash; and Disposable, Minilab 400 on Hard behind a plastic lens.

The film base: On Android phones whose camera offers a contrast curve, Clack takes the frame flat, with the phone’s local tone mapping and color enhancement off, before the film. On other phones the films run on the phone’s own frame.
Not a push: The Digicam, Clack’s one digital camera, has a Contrast dial too: the camera’s menu setting, not a development.
Free or Pro: For seven days of shooting every film is open. After that the free tier keeps one film of your choice, with its dials; Clack Pro has them all.

A model of the films’ data on a phone’s photo, not film. Tested mostly on the CMF Phone 2 Pro.

AndroidGet free access to the closed beta. More about Clack

Questions

What does pushing film mean?: Rating a film faster than its box speed, so it is underexposed, and developing it longer to make up the density. An ISO 400 film shot at 800 and developed for it is pushed one stop; at 1600, two stops. Pulling is the reverse: rated slower, developed shorter.
Does pushing film make it faster?: Less than the rating says. Kodak puts the real speed gained on its color motion picture negatives at under a third of a stop for push 1 and about half a stop for push 2, and says push processing “is not recommended as a means to increase photographic speed”. A push brings back the mid tones’ density and adds contrast; the shadow detail the film did not record stays lost.
Does pushing film increase grain?: Yes. Kodak says a push brings “an increase in contrast and graininess” on Tri-X, and “increased granularity” on its color negatives. Pulling a color negative does the reverse: Kodak calls it “a noticeable improvement in granularity”.
How many stops can you push film?: Black and white goes furthest: Kodak gives times for Tri-X 400 at EI 3200, three stops, and Ilford says HP5 Plus gives “good results” to EI 3200. Kodak publishes two-stop pushes for Portra 800. Fujifilm allows Velvia 100 one stop with little change and two “depending on the scene”. Kodak did not recommend pushing Kodachrome 64 at all.
Can you push Portra 400?: Labs push it, but Kodak publishes no push data for Portra 400; its push times and curves are for Portra 800. A push of a color negative mostly adds contrast and grain. For low light a faster film is the better answer.
Should I push 400 film to 800?: Often there is no need. Kodak says Tri-X can be underexposed by one stop and developed normally, with “a slight loss in shadow detail”, and color negatives have latitude on the underexposed side too (Kodak gives Gold 200 two stops). A one-stop push mostly adds contrast.
When should you pull film?: When a roll was overexposed by a stop or more, or to soften a contrasty scene. Kodak gives a pull time for its motion picture negatives, but none for C-41 still films, and color negatives hold overexposure well without one: Portra 400 rated at 200 and printed normally comes out almost as it does at box speed.
Can you push only some frames on a roll?: No. Development is one time for the whole roll, so every frame gets the same push. Shoot the roll at one rating, or cut the film in the dark and develop the pieces apart.
Can Clack push film?: Clack has no film to develop: it is a camera app that runs film models on a phone’s photo. Its Contrast control has four steps, Soft, Normal, Hard and Harder, which are each film’s development pulled one stop, normal, pushed one and pushed two, with the grain coming with them.

Sources

Kodak, Tri-X, T-MAX, Portra, Gold, Ektar, Vision3, Kodachrome and D-76 are Kodak’s or Kodak Alaris’s; Ilford and HP5 are HARMAN technology’s; Fujifilm, Superia and Velvia are Fujifilm’s. Clack is not affiliated with any of them.