Testing film - did I do it wrong?

Discussion in 'B&W: Film, Paper, Chemistry' started by modafoto, Sep 19, 2005.

  1. modafoto

    modafoto Subscriber

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    Hi

    Yesterday I tested Delta 100 using this method (part II here).

    I ended up finding EI 160 to be optimum. I am surprised to find it 2/3 stops higher than the ISO rating. I developed for 14 minutes in Rodinal 1+50 with 1 minute agitation to start with and 5 sec every minute.

    Did I do the test wrong?


    Morten
     
  2. mono

    mono Subscriber

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    No, I think not!

    I came to EI 200 in xtol 1+1 Kodak agitation modus!
    Examples: Front page of MonoArt...
     
  3. JHannon

    JHannon Member

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    How can you go wrong with Rodinal? :smile:
     
  4. modafoto

    modafoto Subscriber

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    Thanks :D

    I will be continuing my tests and I hope that the result will help me a lot. I am very happy with the film, but it is hard to tame when shooting outdoor. I can use it @ EI 100 in the studio and develop for 12 minutes (for greater skin tones) but outdoor...it is harder.
     
  5. JHannon

    JHannon Member

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    Morten, I have never tested Delta 100 but when I did test Tri-X, FP4, the ISO was lower than the rated value. I have heard that sometimes variations in shutter speed and meter accuracy can make it appear higher. From what I read it is best to use avoid the slower shutter speeds when testing. Keep it at 1/60 or 1/125 if you can.

    Just some ideas...

    Regards,
    John
     
  6. modafoto

    modafoto Subscriber

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    Thanks. I will try this. I shot most of the test with 1/15 on a tripod. I will try the 1/60 and 1/125 if anything goes wrong.
     
  7. Paul Sorensen

    Paul Sorensen Member

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    You might take a look at Les Mclean's book and his film testing method. It seems to me to be easier. That said, shouldn't it be based on your own personal needs and preferences? Perhaps you were looking for higher contrast than what is considered "standard." In that case you might want a higher ISO and longer dev time than the box indicates.
     
  8. Bob F.

    Bob F. Member

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    The proof of the pudding is in the eating... How do your real (as opposed to test) negatives print?

    It is unusual to get higher speeds, but not unheard off. One of the problems with that method in the article is in deciding which exposure is actually maximum black. When doing this myself, I have found around a third-stop difference depending on the intensity of the light under which I examine the test prints. Best idea is probably to examine the tests to find max-black time under the same type and intensity of light that you expect to display them.

    Also, I'm not keen on the idea of using any old metering method as suggested in the article. Expose for the shadow detail and use Zone placement: that sort of method (or equivalent) is the only way to get consistent exposure data for such tests. Relying on in-camera or general reflectance meter readings is too hit and miss.

    Cheers, Bob.
     
  9. Gerald Koch

    Gerald Koch Member

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    What you have established for this film is your own personal exposure index. Such personal exposure indices are dependent on the users camera, developing method and equipment, personal contrast preference, ... When you do this you are not disproving the ISO rating that Ilford has determined for this film.
     
  10. Ara Ghajanian

    Ara Ghajanian Member

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    I know I'm going to get slapped for this one, but...

    If you regularly scan your film could you adapt this test? I honestly have no way of making darkroom prints, but I do want to standardize my processes.
    Ara