Two Hard or No Harder or ??

Discussion in 'B&W: Film, Paper, Chemistry' started by dancqu, Dec 4, 2004.

  1. dancqu

    dancqu Member

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    Perhaps it was not the case many years ago but it is generaly
    understood that today's print and film silver gelatin emulsions are
    hardener incorporated. Perhaps they are only more hard now than
    in the past.

    My question is, will the use of in process hardening render the
    emulsion two hard or no harder or less hard? For that matter
    can an emulsion be too hard? Dan
     
  2. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member

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    Hardener is only meant to protect the emulsion when the print is wet. Most modern papers don't really need it. It will increase toning times and can make spotting more difficult.
     
  3. clogz

    clogz Subscriber

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    As far as I know Efke films are the only ones for which a hardening fixer is recommended.
     
  4. dancqu

    dancqu Member

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    I'm not sure that makes sense. Emulsions are wet from the developer
    on. In-process hardening is in the fix, away from the high ph
    gelatin swelling alkaline developer.

    "Most modern papers don't really need it" Is that because they've
    already plenty of the incorporated type? Dan
     
  5. Tom Hoskinson

    Tom Hoskinson Member

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    Speaking from personal experience, hardening fixers are not needed with the Efke films. It is necessary to be careful with them when the emulsion is wet - but this is a good general practice anyway.
     
  6. clogz

    clogz Subscriber

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    To tell you the truth, Tom, I'm not talking from personal experience but I got this info from the Fotoimpex (J&C) website.

    Hans
     
  7. rbarker

    rbarker Member

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    That's hard to say. (sorry, couldn't resist)

    The only film I use a hardening fixer with is Polaroid PN-55, because the emulsion is scratch-prone even when dry. I've also heard the same suggestion for Efke films, but haven't tried any Efke yet. For prints, I avoid hardeners altogether, as it affects toning.
     
  8. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member

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    There are hardeners that have been used at the development and stop stage, but those have been even longer out of fashion. I'm guessing is that the case for using a hardener at the fix stage was to protect the print in the wash, since the archival washer with separate compartments for each print is a relatively recent innovation (1970s or so?), and before that you had things like the Arkay Rotary Print Washer, where prints sloshed around in a hopper--a much more potentially hazardous situation than being moved from the developer to the stop to the fix.
     
  9. dancqu

    dancqu Member

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    Some may have caught the Two for Too. That was a little play
    on words as I was thinking both 2 and too; two, 2, hardenings
    being too much hardening.

    Apparently the one incorporated must be lived with while the one
    included while fixing is optional.

    Dr. Chapman who writes for Photo Techniques included in one of his
    articles a graph on which a non-hardened and a hardened emulsion
    were compared. Gelatin swell is plotted against ph. Swell is least
    at ph 5 +/- a tenth or two. Both curves rise symmetrically on
    either side of that value.
     
  10. jnanian

    jnanian Advertiser

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    if you do large format work, you will not be able to retouch negatives with lead, if the emusioned was bathed in hardened fixer. you will also have a harder time washing chemistry out of your negatives and prints.
     
  11. gainer

    gainer Subscriber

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    Certain developing agents tan the gelatin in proportion to the image density. Hydroquinone, catechol and pyrogallol are the ones we commonly use. I use a process of bleaching and redeveloping in a staining-tanning developer for negative intensification. I sometimes repeat the process. Once I did it one too many times and tha emulsion cracked in certain places as a result. It surely had a strong stain image, though.