Is there a general rule regarding a preference for pushing a slow film or pulling a fast film? For example: I want to shoot at EI 800. I have an EI 400 film that I could push up to 800, and I have an EI 1600 film that I could pull down to 800. Is there a generally prefered choice? I would expect that the 1600 film might look better pulled down to 800 than it does at its rated 1600, but would it look better than a 400 pushed to 800?

-- Ollie Steiner (violindevil@yahoo.com), March 03, 2002

Answers

Pushing actually does nothing to increase the true speed of a film. The inertia point, or the start of the toe of the film, which in turn determines the amount of shadow detail you get for a given exposure, stays firmly fixed.
Further, there is no B&W film on the market with a true speed of 1600 ISO. A so-called 1600 speed film might just have a true speed of something close to 800 ISO (unless it's Neopan 1600, which has an almost identical sensitivity to Neopan 400).
So, if you want more shadow detail than a 400 ISO film gives, your only real choice is a faster film, like Delta 3200, or TMZ3200. Both of those have a real ISO speed of around 1200.

-- Pete Andrews (p.l.andrews@bham.ac.uk), March 04, 2002.

I agree with Pete that you will probably be happier rating Delta 3200 at 1600 than with pushing a 400 speed film. That said, I have heard good things about Delta 400 pushed to 800, but haven't tried it myself.

-- Ed Buffaloe (edb@unblinkingeye.com), March 04, 2002.

I ran some 3200, with a rating of 1200 and got no shadow detail. I have not run any film test yet, but will not be surprised if it drops to 800-1000 for my equipment and methods.

-- Ann Clancy (clancya@attbi.com), March 04, 2002.

Besides diminished shadow detail, pushing increases contrast and reduces exposure latitude. Many situations that call for high film speed are in available light, where the light source is often in a less desirable location and contrast can be high (harsh shadows). Better to start with a faster film than push.

-- Tim Brown (brownt@flash.net), March 04, 2002.

Without conducting any scientific tests but shooting many rolls in concert and club situations, I compared Delta 400 pushed to 800 and 1600 with Delta 3200 pulled to 1600 and 800. Developing both in XTOL 1:1, I found the Delta 400 pushed to be noticeably superior in grain, and overall tonal gradation than D3200 pulled. I was quite surprised at the results, especially at 1600!

-- Ed Berger (eberger@attglobal.net), March 04, 2002.

My conclusion after years of wrangling with this is that I get overall higher quality with small format by pushing an EI 400 film a stop or more than using an EI 3200 film at a slower speed. Or iow, Delta 400 or HP5+ at EI 800-1200 is superior to Delta 3200 at EI 1200-1600 in all qualities except that it definitely doesn't contain as much shadow detail/density.

In larger formats (6x7) my decision is frequently the reverse; for my usual print sizes framed an hung on the wall, the superior tonal reproduction of the faster film at its "normal" speed is obvious while the increased graininess isn't visible except with close inspection.

-- John Hicks (jhicks31@bellsouth.net), March 05, 2002.

Many thanks to you all for your thoughtful answers to my question. I've printed them out and saved them in a looseleaf notebook on B&W which I keep. And thanks to greenspun.com for providing this- It's great to be able to access so many helpful answers with one click. Like having a textbook custom made to my interests.

-- Ollie Steiner (violindevil@yahoo.com), March 08, 2002.