Pushing Film - What Density Readings?

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Ok, if I calibrate a film/developer for normal I look for the combo of exposure/dev time that gives densities of .1 for zone 1 and 1.15 for zone 8. Zone 5 is something in the .60s
When I push a film what densities should I look for? Do I forget about zone 1 and just try and make zone 5 come in the .60s again? And what happens to zone 8? is it still 1.15 or is it higher? Thanks...

-- Russell Brooks (russell@ebrooks.org), October 18, 2001


"Expose for the shadows, develop for the highlights" - is still the best rule of thumb to go by.
The usual (some would say only) reason for pushing film is to bring a low contrast subject up to a normal printing density on the negative, and you should develop to get the highlights to whatever density you consider 'normal'.
If you get highlights of 1.15 density with a normal contrast subject and normal development, then you should aim for the same highlight density from your low-contrast subject.
Pushing a normal contrast exposure just gets you blocked up and unprintable highlights.

-- Pete Andrews (p.l.andrews@bham.ac.uk), October 18, 2001.

If by pushing you mean rating the film at a higher EI during exposure then you will get lower densities. You won't be able to compensate for lost shadow detail by developing longer. Exposure controls density, development controls contrast.

You will lose shadow detail; the low zones are significantly affected by underexposure. You will get a contrastier negative because the high zones won't be affected as much; Zone 8 will be less dense but not as thin as, say, Zone III compared to film exposed at your normal EI. If you develop the film to get the same density for Zone 8 you'll get a "normal" looking print with dark, impenetrable shadows -- I'm not saying that's bad, it may actually be the effect you're looking for.

-- Bong Munoz (bong@techie.com), October 18, 2001.

I don't think the previous answers addressed your question. First, look at your "normal" densities. If you check out most film calibration articles or books, the recommended density for Zone V is in the 0.65 to 0.75 range, and the density for Zone VIII would be in the 1.25 to 1.35 range, IF you are using a diffusion enlarger head. The values for a condenser enlarger would be slightly lower.

If you develop your film for a longer time, the increase in density is not linear for all Zones, which is what allows you to achieve the desired effect of increasing the contrast of the negative relative to normal development. The Zone I will not change very much, Zone V will change more and Zone VIII will change even more.

To achieve an N+1 development, expose for Zones I and VII, and increase your development until the Zone VII exposures match your normal Zone VIII density. You will notice that Zone I does increase some, and you might want to decrease your initial exposure by an amount that brings Zone I into the normal 0.1 above base and fog density. That might only be 1/3 stop or so. Development for higher than N+1 would require greater reduction in exposure. How much reduction is a function of any particular combination of film and development method. You would have to experiment to find what YOU need to do. This can be tedious, but it can be rewarding, too. Don't get so caught up in worrying about it that you don't take pictures. That can happen.

-- Don Welch (donwelch@hotmail.com), October 26, 2001.

The last answer is getting closer to what I am looking for. But now another question: is N+1 the same as a 1 stop push? I mean do I still shoot and develop a zone VIII for zone VIII? Or am I moving a zone VII up to a zone VIII density? thanks...

-- Russell Brooks (russell@ebrooks.org), October 29, 2001.

I would say that N+1 is the same as pushing the film 1 stop. However, you will find "pushing" and "pulling" used for either exposure or development changes, or both. The Zone System, in its many forms, is more precise as to what constitutes a normal negative, or the deviations from normal.

N+1 results in the increase of density of a Zone VII exposure to match the density of a NORMALLY processed Zone VIII. This is accomplished by increased development time. (Although you may have to compensate for the slight increase in Zone I density by a slight decrease in exposure, as I said in the first answer.)

N-1 is accomplished by reducing development time to the point where the density of a negative exposed for Zone IX is lowered to match a NORMALLY processed Zone VIII. (And you may have to slightly increase the initial exposure to counteract the slight lowering of Zone I density)

Other Zones react to the change in development, of course. Lower densities react less and higher densities react more. If you expose a scene that contains a full range of light values and develop it for N+1, Zone VII will go to Zone VIII, by definition. Zone V will be somewhere between a normal V and VI. If the scene contained Zone VIII values to begin with, they will now be higher than Zone IX, because they were denser than Zone VII to begin with, and they react even more than Zone VII to the increased development.

-- Don Welch (donwelch@hotmail.com), October 29, 2001.

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