Pulling Ilford HP5+ to ISO 3

Samples, Recipe, Discussion, and Development Times

7 min read by Dmitri.
Published on January 7, 2025.

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Ilford HP5+ is a ninety-year-old¹ black-and-white film known for its versatility, sharpness, and controlled response to various development methods. Many photographers love to push-process it and occasionally pull-process. Yet, to my knowledge, no one has pull-processed it to this extreme; thus, this may be the first time anyone has ever shared the technique and the results with the HP5+ shot as if it’s an ISO 3 film. In this article: What does it mean to pull film, and how is it usually done? Why would anyone shoot HP5+ as an ISO 3 film? Metering for EI 3. Development times and technique. Scanning and post-processing. More samples. Next steps. Support this blog & get premium features with GOLD memberships!¹ — HP5+ formula is 94 years old in 2025 if you count dry plates. It was introduced in 1931 as Ilford HP, which stands for Hypersensitive Panchromatic. This is the fifth updated revision of this film.

What does it mean to pull film, and how is it usually done?

Box speed (i.e., ISO speed marked on the box the film comes in) can be measured and calculated based on a film characteristic curve¹ and/or deduced based on practical experimentation. Box speed is often part of the name of the emulsion, for example, Kodak Portra 400, where 400 is the film’s ISO/box speed.

However, film’s sensitivity may be decreased by shortening the development times (i.e., “pulling” it out of chemicals early), decreasing the temperature, or diluting the chemicals. This means that you could meter Portra 400 as if it were an ISO 200 film and get an accurate exposure by altering the development process.

☝︎ Further reading: “A Beginner’s Guide to Push & Pull Film Development.”

¹ — “Emulsion Speed Rating Systems,” G. S. Allbright, 1990.

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Ilford HP5+ shot at EI 3. I used this image as a hero poster in one of the recent articles on Analog.Cafe — no one has noticed anything different! Note that I’ve adjusted the contrast after scanning.

Why would anyone shoot HP5+ as an ISO 3 film?

Pulling film will usually decrease contrast and maybe even decrease grain size. Development times for colour and black-and-white films will often include times and temperatures for pulling it one or two stops. However, the experiment described in this article involves pulling Ilford HP5+ seven stops to EI 3². Such extreme has never been attempted to my knowledge.

So why would anyone shoot an ISO 400 film as if it were a significantly less sensitive ISO 3 film?

I did it for fun and to push the boundaries of what’s possible, but there are also practical reasons:

Shorter development times. According to the Massive Dev Chart, HP5+ needs six minutes in Rodinal with 1:25 dilution, whereas ISO 3 calls for less than four minutes.

Using less chemicals. Greater developer dilutions can save a few cents here and there, or you may just not have enough for your film at the time, which is when this technique could be useful.

Natural/exotic/weak developers. Last year, I used weed and other naturally occurring phenols to develop this film. Those developers are much weaker than the industrial-strength chemicals. In fact, they may not be capable of bringing HP5+ up to its box speed at all (as they may completely exhaust before the development is completed). Because of that, the film needs to be pull-developed to produce workable results.

Fast lenses and slow shutter speeds in daylight without an ND filter. If you have an 𝒇1.4 lens and would like to get all the bokeh, it can produce in daylight, or if you want to smudge motion with a slow shutter speed, you will need to use an ND filter to cut some of the light that enters the camera. However, this will also block the light entering the viewfinder, which can make photography challenging (or there may not be an ND filter available for your camera). Pulling film solves this.

In full sun, you can shoot the 𝒇1.4 lens with an ISO 3 film and a shutter speed of 1/500s.

² — I used ISO in the title of this article as a familiar term; however, HP5+ and other films have just one ISO value calculated by the manufacturer. All other user-assigned film speeds are more accurately referred to as Exposure Indexes (EIs), which is what I’ll be using here going forward.

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Ilford HP5+ shot at EI 3. Rodinal 1:25 for 4min. Slight contrast adjustments after scanning.

Metering for EI 3.

EI/ISO 3 is not such a crazy number for film speed, especially in daylight. You can get good results without a tripod with a common 𝒇2.8 50mm lens in full sun if you set your shutter speed to 1/125s. You can use this as a basis for your metering with the techniques discussed in this article with a manual film camera. I used my Nikon FE with the ASA (ISO) dial set to 12 and exposure compensation set to -2.

Development times and technique.

Massive Dev Chart, which is the world’s largest repository of black-and-white film development charts, lists the lowest film speed for HP5+ as 25 (in Rodinal). But to beat all records at EI 3, we need to give this film three stops less of exposure in development.

There’s a rule of thumb when it comes to pushing and pulling film: either add or subtract 25% of development time for each stop, respectively. This would’ve yielded 3min with Rodinal at 1:50 dilution. However, I decided to extrapolate the development times from the existing ones based on the weakest dilution instead. So instead of going with the above, I guessed 4min with 1:25 dilution (which, based on the times in the chart, would give less exposure to the film). Based on the results I’ve got, I think it would be safe to keep the film in Rodinal at 1:25 for 3min 30sec or even shorter.

I used the standard agitation method, which is about 10 seconds every minute.

Scanning and post-processing.

The common complaint about pulling film by more than one stop is loss of contrast. This experiment confirms this observation, but I don’t feel like it should be considered a hindrance or an excuse, at least when it comes to combining HP5+ and Rodinal. I found it very easy to restore contrast with the Curves adjustments after scanning (darkroom printing techniques could also be used to restore contrast).

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Ilford HP5+ shot at EI 3. Rodinal 1:25 for 4min. No contrast adjustments (left), some contrast adjustments (right).

The negatives I got after pulling HP5+ seven stops looked dense, yet that gave me no issues during scanning. I believe this could be improved by reducing the development times.

Some photographers claimed dramatically reduced grain size when pulling film — I did not notice that to be the case with HP5+. Rodinal is known to produce sharp full-sized granules; it’s possible it may become smaller with a more advanced developer designed to dissolve the grain — but that’s an experiment for the future.

More samples.

To produce this experiment, I used one of my bulk-rolled 12-exposure 35mm rolls. I’m sharing my seven best images from it, which I must admit is a better “keeper” rate than normal. Luck has certainly played its role, but the fact that the film is able to retain the detail so well at this exposure and respond gracefully to editing has undoubtedly helped.

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Ilford HP5+ shot at EI 3. Rodinal 1:25 for 4min. Some contrast adjustments.

View this image in HD with GOLD

Ilford HP5+ shot at EI 3. Rodinal 1:25 for 4min. Some contrast adjustments.

View this image in HD with GOLD

Ilford HP5+ shot at EI 3. Rodinal 1:25 for 4min. Some contrast adjustments.

Next steps.

I felt that the experience of pulling HP5+ seven stops until it behaves like an ISO 3 film is a positive one. It wasn’t difficult to get good exposures, and the film produced all the details I’d expect from it when shooting at box speed. It was quick to develop and not particularly difficult to scan.

But that’s not the only thing I did to HP5+. Tomorrow, I will publish the next article where I share my results pushing HP5+ to EI 100,000! That was a lot more difficult to do, yet I still have something to show you.