Film Friday #25: Pushing and Pulling Ilford’s HP5+

Ilford HP5 pushed

Hello, kids! Today, we will be talking about pushing and pulling film in relation to over and underexposure. The film we will be using for today’s lesson will be Ilford’s HP5+, as it lends itself well to being pushed around like a wheelbarrow on a pumpkin patch.


Ilford HP5+

The ISO/ASA speed on the package of various films will tell you what you should shoot. HP5+ is a 400 ASA film. It’s Ilford’s recommended speed for the best results. However, if you read the datasheet, you will see that its stated that a good image quality will also be obtained at ratings up to 3200ASA. What does this mean?

The ISO/ASA of the film refers to the sensitivity of the film to light. The lower the number, the less sensitive it is, hence needing more light. The higher the number, the more sensitive it is hence needing less light. So an ISO 400 film is more sensitive than an ISO 50 film, and therefore needs less light to produce images. This comes at a compromise in the form of less sharpness with more grain on film and noise on digital sensors.

So pretend that you’re shooting an event outside, and that the sky is getting darker. The fastest lens you have only goes up to f/3.5 and only film you have is HP5+. Your shutter speeds are already going the slowest it can go before getting camera shake. So what do you do? Why, you underexpose and push, of course!

Load the HP5+ into your camera, and set the ISO dial of your camera to 1600 so it thinks that you’re shooting an ISO 1600 film. Now you’re underexposing your film by two stops because less light is hitting the film that isn’t as sensitive as it could be. Later, when you are developing, you will develop for longer to compensate for the underexposure.

This does two things to the film. One, it makes it grainier. It’s great if you like grain, I know I do. You can try underexposing a tabular grain film like Ilford’s Delta or Kodak’s T-Max if you want to minimize grain. The second thing that happens is added contrast. This happens because with negative film, you would add more to the highlights while the shadows stay the same when underexposing. Depending on the film and developer used (and some developers do work better than others for push development) you might be able to maintain more detail in the shadows.

And then there is pulling film. As you might infer, this involves overexposing the film. It’s more popularly done with colour film, to increase saturation while reducing contrast and preserving detail in the highlights and shadows. So you would shoot a film like Portra 400 as if its a ISO 200 film. But with colour film you would develop it normally with no change, as the development times tend to be rather short anyways. Plus if developed for a shorter time they would produce very flat images.

Why might you want to push or pull film? Besides being able to shoot in less than ideal conditions or compensating for potential exposure error, underexposing, for example, lets you shoot at faster shutter speeds with the aperture stopped down on sunny days. This is great if you’re looking to zone/scale focus, as being able to shoot at f/16 for longer would be a lot easier to zone focus with. Overexposing would also help with saving highlights or shadows in case you want to be able to have more information in the image.

The reason we chose HP5+ for Film Friday in relation to pushing/pulling this week is pretty simple. It’s the fact that it copes with being over or underexposed very well. I like how it looks underexposed two stops, for example. I’ve expressed my adoration for grain and contrast before, as I’ve always liked that intense and gritty sensibility in my photos. HP5+ at IS0 400 has always been too low contrast for my taste. In fact, whenever I shoot HP5+ I only ever shoot it as if it’s 1600 iso now.

I know we’ve covered HP5+ for Film Friday before, but since we’d like to encourage people to experiment and HP5+ is very versatile for that purpose, it’s going to be 10% off in all available formats again tomorrow and Saturday.

Here’s what HP5+ looks like when pushed to ISO 1600, shot through various cameras:

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Beau Photo Supplies Inc.
Beau Photo Supplies Inc.