A Beginner’s Guide to Push & Pull Film Development

What, Why, and How?

11 min read by Dmitri.
Published on . Updated on .

Film ISO is determined by the manufacturer for optimal performance. Usually, this means the finest grain and the most accurate colour with standard development times and temperatures.

But we can also change film’s sensitivity during development to suit our photographic needs or to create a specific look.

In this short guide, I will explain what pushing and pulling film is exactly. I will also show you some examples of push- and pull-processed black and white, colour, and cross-processed film.

Push and pull development can be done at (some) labs, thus you don’t necessarily need to know how to develop film at home. However, they will typically charge extra for the service.

What is push/pull film development?

Pushing film means leaving the emulsion in the development chemicals for a longer time. This increases its nominal light sensitivity.

For example, you can push-develop an ISO 100 film +1 stop to behave like an ISO 200* emulsion. Because your film behaves like an ISO 200 film, you should also set your light meter to ISO 200 when metering your scenes.

Pulling film means leaving the emulsion in the development chemicals for a shorter time (i.e., pulling the film out of the tank early). This decreases its nominal light sensitivity.

For example, you can pull-develop an ISO 100 film -1 stop to behave like an ISO 50 emulsion. When doing this, you should set your light meter to ISO 50 when metering your scenes.

You can push or pull any modern emulsion. However, doing so will increase the grain size (more so while pushing), likely decrease the dynamic range of your film, increase contrast (while pushing)/decrease contrast (while pulling), and alter the saturation (when dealing with colour films).

Some films will allow you to push or pull them up to five stops while still giving a workable image. Others will degrade significantly after one or two stops.

When pushing or pulling black and white films, different developers and developing techniques may give you various results in terms of grain and contrast.

✱ — Technically, the film’s ISO rating does not change as it’s pushed or pulled. Instead, a new exposure index (EI) is used to set the light meter value. But to keep things simple in this article, I refer to EI as “ISO” and disambiguate these terms in the glossary section below.

Kodak Portra 800 pushed to EI 3200 (+2 stops). Shot with Hasselblad XPan.

Why should you push or pull film?

Changing light conditions may require you to push or pull film. For example, if you’ve got an ISO 50 film, expecting to have a photoshoot in bright sun, you may suddenly need an ISO 200 film if the clouds unexpectedly cover the sky. Should that be all you’ve got, you can set your light meter to ISO 200 and then ask the lab to push your film +2 stops.

Shooting in subdued light without flash (especially when it comes to colour film) will have you pushing your film as well. For example, if you’re planning to shoot during the blue hour (an hour after the sun sets), an ISO 800 film may not be enough; unfortunately, that’s the fastest colour film in production, and thus, you’ll have to push it one or more stops to get usable images without having to use a tripod.

Shooting fast action that needs the fastest shutter speed will often also need a fast emulsion, and the current selection of films may not be adequate. Pushing your film can solve that limitation.

Using film with infrared and some colour filters sometimes calls for an ISO much higher than what your film shows on the box. When it comes to infrared, the options are limited; thus, pushing your film is the only way forward unless you’re willing to mount your camera on a tripod.

Shallow depth of field in full sun may be impossible with ISO 100 film or faster unless your camera has a very fast shutter. Unfortunately, few colour film options are below ISO 100, but pulling your emulsion one or two stops can help you achieve the bokeh effect you want.

Motion blur and long exposures in daylight will also require slow ISO values, where pulling may be your only choice.

Toy/reusable cameras may work best with an ISO 25 in full sun; since it is an uncommon film speed, pulling may be your best bet.

Stylistic effects, such as grittier grain than usual and higher or lower contrast while preserving the film look, can also be achieved with pushing or pulling.

Ilford HP5+ pushed to EI 1600 (+2 stops). Shot with Minolta TC-1.

Camera settings for pushing and pulling film.

Your lab or developing times (if you process film at home) are responsible for pushing or pulling. However, you must adjust your camera settings or your light meter as well.

Pushing film involves nominally increasing your film’s sensitivity. Thus, for example, if you’re pushing your ISO 100 film +1 stop, you should set your camera’s ISO dial (or your external light meter) to 200.

In other words, pushing +1 stop requires you to under-expose your film by 1 stop. Whereas pulling -1 stop requires you to over-expose your film by 1 stop.

Not all film cameras can shoot in manual mode (which is how you can use an external light meter) or have an ISO dial. Newer film cameras will read the DX code off your film and automatically set the ISO to the box speed. Some may allow you to override this, and many will not. Thus, pushing or pulling your film with most point-and-shoot cameras is challenging. Your only option may be to cover up the DX code with a sticker, learn your camera’s default ISO setting (usually 100 or 25) and then rate your film at that speed to push or pull. However, that may not be practical.

Toy/reusable cameras mostly have fixed aperture and shutter speed (typically 𝒇8 and 1/125s). For best results, they should be used in consistent lighting or with flash. You can certainly push or pull your film with these cameras while keeping those limitations in mind. For example, an ISO 25 film is ideal in full sun 𝒇8 and 1/125s, which calls for pulling if you have a more common ISO 100 film speed available.

CineStill pulled to EI 320 (-1.3 stops). Shot with Minolta TC-1.

Pushing and pulling film at the lab.

Before you push or pull your film, you should do a little research:

1) Has anyone done it already, and what do the results look like?

2) Can your lab perform this service?

Pushing and pulling is free if you do it at home, but in the lab setting, it requires additional time and attention; you should be prepared to pay a little extra for this service.

Pushing and pulling film at home.

Before you push or pull your film at home, find out:

1) Has anyone done it already, and what do the results look like?

2) Do you have the development times to do this right?

If you’re developing black and white film, you add 25-33% of development time for each stop pushed or subtract the same for each stop pulled. To calculate this, convert your time to seconds (i.e., 3min 30sec is 3×60+30 = 210sec) then multiply by 1.25 to add 25% or 0.75 to subtract 25% (i.e., 210×1.25 = 263sec).

You can then convert your total seconds to minutes and seconds (i.e., 263/60 = 4.38min; the remainder can be converted to seconds by re-calculating the minutes 4×60 = 240 and subtracting from the total: 263-240 = 23seconds; thus your new time is 4min 23sec).

Colour negative film will often have a chart of times (like the one attached below) with your developer as all C-41 emulsions use identical times and temperatures.

3) Consider these development techniques:

If you’re shooting black and white film, you may also want to research which developer and dilution is best for the job. Whereas altering time is usually the easiest way to do this, dilution and temperature are also important factors you may want to consider. For example, instead of developing your film quickly, you may want to dilute your chemicals or develop at cooler temperatures so that you don’t have to be as precise with your clock.

Stand development can also give you more time; however, you should watch out for bromine drag, which can occur if you don’t agitate your film (whereas agitation may further increase the contrast, which may already be high during pushing).

Colour negative film (C-41) push- and pull- development times.
Fujifilm Natura 1600 pushed to EI 3200 (+1 stops). Shot with Minolta FED 5B.

Which films work best with pushing and pulling film?

If you’re going for a specific effect, seeing samples is probably the best way to find out. But in general, films that keep their contrast and grain in check for as many stops pushed/pulled as possible are considered the safest for the job.

Black and white negatives. Ilford HP5+, Kodak Tri-X, and Kodak T-Max P3200 are famous for their relatively consistent grain and contrast while being pushed or pulled. Older/traditional black and white emulsions (as opposed to T-Grain) are usually the best choice for the job.

Colour negatives. CineStill 800T works very well for pushing and pulling, which may be a surprise as it is also usually cross-processed in C-41 chemicals (originally made for ECN-2). I’ve had good results pushing Kodak Portra 800 +2 stops, and some have reported good luck with pushing Kodak Ultramax up to +2 stops. I even managed to push the out-of-production Fujifilm Natura 1600 +1 stop to 3200.

Slide/reversal film. Kodak Ektachrome responds well to being pushed up to +2 stops (maybe even further). Some older, out-of-production films, such as Fujifilm Provia 400X, can also behave exceptionally well when pushed.

Which developers work best with pushing and pulling film?

There’s little choice when it comes to developers for colour film, but black and white emulsions have many options. Some of them work better for pushing and pulling than others. Unfortunately, it’s hard to rank them as the results also vary based on the film in question and the development technique. Some report Acufine and X-Tol as good options at greater dilutions, whereas this article shows an entire chart of developer options just for HP5+, where X-Tol seems to persist as the best option for both pushing and pulling.

New Classic EZ 400 pulled to EI 100 (-2 stops) in Ilford Ilfosol 3 (1:9 dilution for 3min 20sec) with Minolta P’s.
Kodak T-Max P3200 pulled to EI 800 (-2 stops). Shot with Voigtländer Vitessa L and green filter.
Ilford Pan 400 pushed to EI 1600 (+2 stops). Shot with Canon Canonet QL25.

Glossary.

Box speed — a manufacturer’s film ISO rating. If the film has a DX code, it will be set to this speed. Box speed is also often in the film’s name; for example, Portra 400 has a box speed of ISO 400.

Film speed — same as film sensitivity, ISO/ASA/DIN/etc. rating. Film speeds are typically calculated using scientific instruments based on well-documented formulas. However, some brands, especially the ones that repackage emulsions, may rely on experimentation and personal preferences to set the box speed.

DX code — a strip of metal and black squares on the canister that automatic cameras use to read the film’s box speed.

Nominal film speed — whereas box speed or film ISO is determined by the manufacturer, nominal film speed is an assumed film sensitivity based on the development method. For example, a film with a box speed of ISO 100 can have a nominal film speed of 400 if pushed +2 stops during development.

Exposure index (EI) — a nominal film speed.

Film rating — it is said that the film is rated at EI 400 if the camera ISO dial is set to 400 (to push it +2 stops), but the box speed is ISO 100. You can also rate your film “at box speed,” i.e., shot normally.

Stops — a logarithmic (base 2) progression of film sensitivities, apertures, and shutter speeds. Learn more about stops here.

Metering — estimating an appropriate aperture and shutter speed for the given film sensitivity. Learn more about using a light meter here.

Film development — a.k.a. film processing is the process of dunking film into specific chemicals in complete darkness to reveal the image. This can be done at home or at a lab. Learn how to develop colour film at home.

Cross-processing — means developing film in chemicals that it was not optimized for. For example, CineStill film is a Kodak motion picture film designed for ECN-2 chemicals but is usually cross-processed in the standard colour negative chemicals (C-41).

Emulsion — used on this blog and many others interchangeably with “film.” More precisely, in photography, an emulsion is a photosensitive mixture of chemicals that coats a plastic base. It’s also possible to coat other materials in photosensitive emulsions.