Push Processing Film (400–3200 asa)


FPP Darkroom Day / Mid-West Meet Up


We received an e-mail from FPP listener Carlos about how to shoot when you intend on "push processing." For those who do not know about "push processing," check out the Wikipedia page here.

Carlos' letter:

So let's say I shoot with the intent of push processing the film (400 - 3200 for example).

1. You underexpose by 3 stops, right? If no, then what kind of exposure adjustments do you need to do.
2. If yes and you somehow mess up on the exposure (ex fingers accidentally rotate the aperture ring or shutter speed dial) and you push process as expected, is there a way to "save" the photos in that roll of film?


Hi Carlo,

To shoot a 400 ISO film at 3200 ISO, yes, you are underexposing
by 3 stops. The only four films I'd personally recommend under-
exposing this much, however, are Kodak Tri-X, TMax 400, Portra
400, and Ilford Delta 3200.

In B&W shooting (the first three films listed), it's always best to
push process/over-develop by the number of stops underexposed.
Chemically speaking, a push of 1 stop is ~25% of the total processing
time added to the standard developing time.

Shooting and pushing color? The whole game changes.

When shooting Portra 400 with the intent of exposing at ISO 3200,
it's typically best to push the film at least 1 stop, and up to a full
3 stops. From my own experiences, pushing 2 stops is a happy
medium, with moderate mid tone and highlight retention, with shadows
that can be "pulled" back to black in Photoshop/Lightroom. I've pushed
a roll the full 3 stops before, but hated the resulting tones and grain.
Pushing only 1 stop is tricky, and should only be done once you're
comfortable playing around with push processing.

Regarding your "messing up the dials" scenario, accidentally over-
exposing the film to be push processed is fine, but even more under-
exposure will typically yield an unsatisfactory image. Highlights can
also easily be "pulled" back in post production. If you do this with a
B&W film such as Ilford Delta 3200, there is a slight chance that
pushing the film even further (4+ stops) could yield an image.

With any kind of push processing, remember, you can't bring up
shadow details that were never there. All pushing will do is over-
process the midtones and highlights in an attempt to bring the shadows
up to an acceptable level. So if the film never actually recorded any
detail in a certain shadow area, all the overprocessing in the world
won't make a shadow appear.

Hope this answers your question, and keep on shooting film!



imagesfromobjects's picture

Hey, guys! Just stumbled across this in a search for this subject. Coincidetally, I've just ordered my first kit of C41 developer from you guys, specifically because I want to try pushing color film, and haven't gotten any willingness from my local labs to do so. I'm also just up for a new DIY analog adventure!

I have a couple follow-up questions. It makes complete sense what you said about the impossibility of magically making shadow detail appear, when it was never recorded. I typically rate all my favorite color negative films at 1/2 box speed, spot metering for the mid-shadows I wish to save, with the exception of Gold 200, Fujicolor 200 and Portra 160, which I rate at 125, 125 and 100 respectively. Thus far I've been happy with the results I get from this method. Dense negatives, easy to scan, lots of detail in the shadows without blown highlights or weird color shifts.

My question(s) to you are- should I change my metering/rating method to simply shoot at box speed? And is there a chart somewhere on the web which lists suggested developing times for pushing color films? At one time, I was sure I saw something on Kodak's site, but for the life of me I can no longert find it. I'm happy to experiment with different methods - to a degree - but I don't want to drastically botch things, so any input or suggestions would be appreciated.




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