Acceptable base+fog levels for HP5 and FP4????

Discussion in 'B&W: Film, Paper, Chemistry' started by naaldvoerder, May 25, 2008.

  1. naaldvoerder

    naaldvoerder Member

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    I think my bulk film is getting fogged. Can anyone tell what should be a toleberal base + fog level for both these films???

    Thanks Jaap Jan
     
  2. Jim Noel

    Jim Noel Member

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    MIne run .07 - .15. I think anything up to about .20 would be tolerable.
     
  3. gainer

    gainer Subscriber

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    You could try removing the emulsion from a sample of film to see how much antihalation dye is in the base itself. Ordinary Clorox will do the removal. Some films use a gray base, others use a dye in the emulsion. The density of the gray base adds to the base density caused by development fog. There are three conditions to test:1) unexposed, fixed. 2) unexposed, developed, fixed. 3) removed emuldion.
     
  4. RobC

    RobC Member

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    Anything upto .2 is normal depending on the developer and dilution. 0.3 is still quite useable as you just print through. What fb+fog are you getting and is it the same both sides of the film?
     
  5. naaldvoerder

    naaldvoerder Member

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    Something like 0.45.....
     
  6. RobC

    RobC Member

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    that is quite high. What developer and dilution are you using and is it fresh?
     
  7. naaldvoerder

    naaldvoerder Member

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    Ilfotec hc mixed from syrup....
     
  8. FilmIs4Ever

    FilmIs4Ever Member

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    Hey, could you post a sample of clear negative base non-inverted?

    You need to tell us the film type, the date of purchase, and the expiration date for us to able to contribute anything relevant besides idle speculation.

    Faster films fog more quickly (even when frozen).

    Storage conditions affect fog rate.

    Ambient background radiation will continue to fog film (especially fast film) even when frozen.
     
  9. RobC

    RobC Member

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    I wouldn't have thought that would cause any problem with either of those films. Certainly looks like a film problem but exactly why I couldn't say.
    As has been suggested, develop a strip of unexposed film and check it for even fb+fog. If it had been fogged from your bulk loader I would be surprised if the fogging was even all over. So if the film does has even fb+fog all over, then it would most likely be a bad batch of film.
     
  10. naaldvoerder

    naaldvoerder Member

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    Thanks a lot, i will do the test...
     
  11. djkloss

    djkloss Subscriber

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    Please forgive my ignorance, but what radiation and where's it coming from?