Push a slow film or pull a fast one?

We read a lot about folks who'll shoot Tri-x at ISO 200 because they prefer the tonality. I know all the arguements about what constitutes a personal ISO, but for the sake of arguement let's assume Tri-X really is a 400 film. So the person who shoots at 200 is overexposing and probably underdeveloping -- the classic advice on exposure. Anticipated results are finer grain and lower contrast.

But would it make more sense, if you wanted to shoot at 200, to push something like Acros, which starts the game with a much finer inherent grain structure than Tri-X? I'm curious to know if anyone has made these comparisons -- for example, is Acros or FP4+ in Acufine better than pulling Tri-x? Even though there's not commonly accepted definition of "better", I'd be curious to know what your experiences have been.

Trask said:

Anticipated results are finer grain and lower contrast.

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I think that is it in a nut shell. In particular the later.
Films are very often used at derated ISO speeds. They
are so used because of the more acceptable contrasts
and gradations achieved. Dan

In my personal opinion, It depends if you want more contrast o less. In the first case, I would reccomend to push Acros or FP4+ while if you want less contrast, pulling TXP is better option

Trask said:

I know all the arguements about what constitutes a personal ISO, but for the sake of arguement let's assume Tri-X really is a 400 film. So the person who shoots at 200 is overexposing and probably underdeveloping -- the classic advice on exposure. Anticipated results are finer grain and lower contrast.

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Actually, there is one detail you are missing: there is no such thing as a personal ISO. There is one such thing as a personal Exposure Index, which is a fundamentally "meaningless" number in that it's just the number you dial on your meter to have the results you want.

In fact, setting your meter at 200 does not mean you are "exposing at 200." It means just that: setting your meter. "Overexposing" a film just means that you use a higher portion of the characteristic curve. It is reasonable to say that someone setting their meter at 200 is not actually overexposing their film, but actually exposing it properly.

But that's an f/63 topic...

Trask said:

We read a lot about folks who'll shoot Tri-x at ISO 200 because they prefer the tonality. I know all the arguements about what constitutes a personal ISO, but for the sake of arguement let's assume Tri-X really is a 400 film. So the person who shoots at 200 is overexposing and probably underdeveloping -- the classic advice on exposure. Anticipated results are finer grain and lower contrast.

But would it make more sense, if you wanted to shoot at 200, to push something like Acros, which starts the game with a much finer inherent grain structure than Tri-X? I'm curious to know if anyone has made these comparisons -- for example, is Acros or FP4+ in Acufine better than pulling Tri-x? Even though there's not commonly accepted definition of "better", I'd be curious to know what your experiences have been.

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It depends on your desired results and personal taste. Try both, try lots of combos, find what works and make pictures. Best. Shawn

By pushing film, you'll be slipping down the slippery slope of very thin low values. It's difficult to print, dust is a real problem, and it accelerates the farther down the characteristic curve of the film you get. By taking an excellent film such as Tri-X, overexposing it one stop and then adjusting your development for reasonable densities in the highlights, you will have a neg that will probably display more grain than Acros at EI200, but it will print much easier and since the negative is generally going to be denser, you can count on dust not being such a big problem either.

Then again, if you like really blocked up low values with pitch black without much shadow detail, then go ahead and push a medium speed film a notch. It might look great! As previously stated, it depends on what you want.

If you shoot sheet film, it's easier, because with each sheet you determine exactly how much shadow detail you want. Then you develop according to the brightness range, or you could use a dark green safelight and inspect the negative after about 60-70% of normal development time. Works like a charm. Roll film is a bit trickier, but it could conceivably be done for that as well if your exposures are extremely consistent throughout the roll.

- Thom

A lot depends on developer too. For example, FP4 Plus in Microphen is in the range ISO 160-200, while HP5 Plus in a fine-grain developer is likely to be in the range ISO 200-259, i.e. there is maybe 1/3 to 1/2 stop between them. This is seldom decisive, so what matters are grain and tonality. Iford's own research (and my own experience) indicates that a slower film in a speed increasing developer will almost invariably be finer grained than a faster film in a fine-grain developer (and it's cheaper too), but entirely personally, I much prefer the tonality of the HP5 in the FG dev.

This is of course an entirely separate consideration from merely increasing or decreasing exposure or development time when considering a single film/dev combination.

Cheers,

R.

Thanks, folks. Interesting thoughts. Obviously the combination of exposure and development both moves the image up and down the curve, and even changes the shape of the curve. As noted, I'll have to run my own tests, and report back. Wonder if it makes a difference that I'll be scanning vice printing? We'll see....

You will generally get good results from scanning by keeping the density of the negative back a hair, while printing is generally easier with a neg that's a little denser.