Pushing is a neat little trick, but don’t default to it
Pushing and pulling are popular film shooting techniques (especially among black and white shooters) that will have a significant effect on how your images look. Since many photographers, for example on YouTube videos, keep bringing up how they always push to EI 1600 etc., you may be under the impression that it’s some mandatory film photography thing that any self-respecting little hipster should always default to. Even thought many films can be pushed, you should always think whether you actually need to, or whether it’ll actually hurt your images.
What is pushing and pulling?
Just in case you don’t know what pushing and pulling (or push/pull processing, to be more precise) is, here’s the gist of it.
Pushing a 400 ISO film one stop to 800 simply means under-exposing it one stop as you’re shooting. By compensating it in the development, with an equivalent amount of ‘over-exposure’ (using development times of one stop faster ISO) the final image will balance out with slightly increased contrast. With a longer development time, the highlights will come out one stop brighter, because the emulsion has more time to get soaked in the developer, but the shadows will get darker by an equivalent amount.
One stop push (shooting it at 800) will increase to contrast some amount and two stop push (at 1600) will double the effect. Pushing the film will generally increase graininess as well.
↑ Portrait on pushed black and white film. These kinds of lighting conditions favour pushing the film; diffused light on an overcast evening. This photo was shot on Kodak Tri-x 400 at EI 1600.
↑ Another example of a pushed portrait shot on similar lighting conditions. No direct sunlight on a very flat ambient light. The combination will produce a very natural and classical look. This photo was shot on Ilford HP5+ at EI 1600.
Pulling film means the opposite compared to pushing. You can shoot a 400 speed film at 200 (one stop pull) or at 100 (two stop pull) for example. It will have just the opposite effect; it lowers the contrast and gives flatter initial tones. By pulling, you’re basically over-exposing the image while you’re shooting. This is for brightening the dark areas (shadows). To balance it out, it’ll get developed with one stop shorter development times. This will leave the highlights darker than they’d be at box speed, because they’ll be sort of “under cooked” by not allowing them to have enough time in the developer. The shadows will be lighter and the highlights will be darker. Ergo, decreased contrast. Pulling the film will generally decrease the graininess.
↑ Example of a candid street photo, on Kodak Tri-x 400 shot at EI 200, in other words, pulled one stop. Even though there’s direct sunlight, that casts hard shadows, the contrast is nice and smooth.
↑ Another example of pulling Tri-x to EI 200. Notice again the direct sunlight. Regardless, the image still holds together quite nicely. The model’s face has some quite unfortunate over-exposure, but other than that, the contrast is nicely in command, despite the high contrast scene.
Too much contrast is… well, too much
Pushing isn’t necessarily the best bet for high contrast lighting situations. For example, a bright summer day doesn’t require pushing and may even hurt your images. If the scene has high contrast as it is, increasing it by pushing may give unpleasant results. The result might be a literal black and white image — an image containing basically just blacks and whites, with very little of middle tones… something like a photocopied page from your art history book.
↑ Kodak T-max 400 pushed to EI 1600 on a perfectly sunny day. The result isn’t far from something that could’ve come out from a Xerox machine. Notice that the lighting conditions are already high in contrast and just how much the two stop push amplifies it.
Remember that more contrast isn’t always better. It is like eating your porridge: you don’t want it too hot or too cold, but juuust right instead. I wish I’d have a penny every time I hear a film photographer say something like “I always push my film to 1600 because I like the way it looks.” Yes, but what it ends up looking, depends on the conditions and they’re never constant. A better idea is to adapt to the conditions and adjust the shooting techniques accordingly.
A high contrast situation could be something like a sunny day with no overcast. As you know, it’ll cast very hard shadows. A scene like this can easily have all the possible EV values in the same frame. The surfaces, that receives direct sunlight could be exposed with an aperture of f16 (according to the sunny 16 rule). The area right next to it, could be under a hard shadow, that could be exposed with an aperture of f4. There’s basically a four stop difference between them which makes the scene very contrasty as it is.
Pushing the film on a scene like this would increase the contrast even more. What would be the point of it? If anything, the contrast should be lowered via pulling.
↑ Another example of an unnecessary push. This is Kodak Tri-x 400, pushed two stops to 1600 on a sunny day. The tonal range isn’t exactly the most pleasing.
Rules of thumb
If you’re uncertain when to push or pull, here’s a good general rule of thumb. Use box speed as your default setting. Think of it as your base-ISO. It’ll get you far.
If you’re getting into low light and/or low contrast situations, consider pushing the film a stop or two. That would be indoors, shit times of the year and crap weather, when the light is flat, dim or diffused.
During the summer, there’s less need or legit reasons to shoot high ISO and you’ll need to manage the hight contrast of sunny days in-camera. Contrast can be added in post, but it’s much harder, in most cases impossible, to reduce. That’s when it’s perhaps a good idea to pull the film. Easy peasy.