density of mfgrs markings on film

Discussion in 'B&W: Film, Paper, Chemistry' started by rexp, Jan 4, 2005.

  1. rexp

    rexp Member

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    I usually shoot Ilford FP4 in 120 format and develop in Perceptol, but last weekend I developed a couple rolls of HP5. Same developer, close to recommended times for development, pretty normal process. There is a large difference in the density of the markings along the edges of these two films (exposure #, film type, etc.). The HP5 is much denser than the FP4. I can't complain about the results of either sets of negatives (I guess that is what matters, isn't it?) but surprised by the text.

    I suppose it could be due to the film speed. If the machine that exposes this info is set up to expose at a constant light flux, then a slower film would appear to be exposed less than a faster film. I would think they would either overexpose enough to compensate for this, or adjust for consistent exposure.

    I am trying to stick with one film until I feel I can utilize its potential (OK - SOME of its potential) as opposed to trying many types of film, therefore I don't know if this is the case with other types of film. Maybe some of you can take a peek at the markings on your films and let me know.

    Interesting......
     
  2. BradS

    BradS Subscriber

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    Wierd coincidece...This morning, I was droping some B&W negs at my lab to have them make prints -- I don't have a darkroom. I had a mix of HP-5 and Plus-X. The guy at the counter noticed the same thing you mention. The frame numbers on the HP-5+ were very dense and those on the Plus-X were a little thin. I just chalked it up to my dev process....figured I shorted the dev on the Plus-X but I think your explanation is plausible too.

    Need more data on this one.
     
  3. pschauss

    pschauss Member

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    I have noticed something similar with Kodak bulk film (Tri-X and Plus-X). The frame numbers on the bulk film are much lighter than those on the corresponding pre-packaged version. I have never seen this problem with Ilford films.
     
  4. rexp

    rexp Member

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    It just dawned on me that I should post this on the Ilford forum. Maybe one of the Engineers will chime in...
     
  5. ElrodCod

    ElrodCod Member

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    That's probably because the film base of the bulk film is thicker.
     
  6. titrisol

    titrisol Member

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    I have noticed that those marks are very variable from film to film... even between lots.
    They are just used for identification so I wouldn;t even give them much thought.
     
  7. rbarker

    rbarker Member

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    Don't bother. None of the Ilford people monitor their forum at the present time. Those who did in the past were terminated several months back.
     
  8. rogueish

    rogueish Member

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    :sad:
    I sad to hear that. I found they were helpful to me with my queries when I was visited the site regular.
     
  9. pschauss

    pschauss Member

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    Is this true of all bulk film or just Kodak? (The Ilford bulk film I have used does not have the lower density labels).

    Does the thicker film base have any impact on EI rating or processing?
     
  10. ElrodCod

    ElrodCod Member

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    Kodak Tri-X is the only bulk film that I've ever used but it may be true of others as well. The only impact that I've experienced is that it's harder to get max black through the thicker film base when printing. Take a piece of processed unexposed negative of each; lay them side by side and make a test strip & you'll see what I mean.