Zone system question

Discussion in 'Film and Processing' started by folker, Apr 25, 2006.

  1. How should I increase/decrease film development for the different
    zones N+/N- with modern films like Acros?

    +/- 10% or 15% or 20%?

    Any advice is appreciated!
    Thank you very much!
  2. The general rule for development is 15 percent equals one stop of exposure development.
  3. Dear Folker,

    As I understand it, the point of the Zone System is that you determine this yourself through exhaustive tests.

    Otherwise, a rule-of-thumb increase/decrease is a lot easier and you can take up any slack with variable contrast paper.

    Slow films are generally more sensitive to variations in development regime than fast ones, and 'new technology' monosize-crystal films(Ilford's epitaxial and especially Kodak's T-grain) are much more sensitive to variations than 'old technology'.

    It took me several rolls of Acros to get results that I liked (varying development & dev time) and I don't use it because I find it too finicky and even the best tonality seemed inferior to Delta 100 as far as I was concerned. Others will probably say the exact opposite, but my point is that films 'like' Acros is not an outstandingly meaningful grouping: TMX, Delta 100 and Acros all respond rather differently.

    With 'old technology' films I find I am quite happy with only three dev times (per film, of course):

    'Normal' = subjects with an average brightness range print well on grade 2-1/2 paper

    -15% = subjects with a long brightness range

    +50% = subjects with a short brightness range

    This will elicit howls of rage from some, and accusations that I am a lousy photographer than others. Tough. I suggest it merely because you might be interested.


    Roger (take a look at The Photo School at for free modules on ISO speed, subject brightness range and more).
  4. As mentioned, test away. I have not found some of the new films, like Acros in particular, to put up well with developing variances. It's one of those films that is hard to get a straight image, let alone use for zone system photography.
  5. "exhaustive tests" not true...

    if you want exact times, pick up a book on the zone system and test, it doesn't really take much time, certainly no more than " several rolls". :)
  6. Dear Mark,

    I have half a dozen books on the Zone System -- I write for the photographic press for a living -- and some 30 years ago I tried the Zone testing bit. I found it substantially a waste of time when I did it, and now I know a great deal more about the sensitometry, chemistry, etc., behind it, I regard it as an almost complete waste of time.

    I am not quite sure about your reference to 'rolls'. Determining multiple, precise N+/- dev times is substantially pointless except with sheet film; if there are multiple subjects with different brightness ranges on the same roll the N+/- must always be an approximation and the wider the range of subjects, the less suited to all is the approximation.

    Some people love and embrace the Zone System, and the very best of luck to them. Many others, who are at least as good photographers, do not. It's a matter of personal preference.


  7. Thank you!
    I have read many books on the Zone System. I have tested my films, but I am tired to test new films, so I thought I can simplify my methods ;-)

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