What's the idea...

Discussion in 'The Darkroom' started by JamesD, Nov 11, 2005.

  1. JamesD

    JamesD Between darkrooms

    Joined:
    Mar 20, 2005
    Messages:
    1,002
    Likes Received:
    3
    Location:
    Living in Snapshot reality.
    behind hardening vs nonhardening fixer? I've read that it should be used with film, but not with paper? What gives? The fixer I have, so far as I know, is non-hardening... does this mean that I can't use it to fix film?

    Thanks
     
  2. terri

    terri Administrator Staff Member Supporting Member

    Joined:
    Sep 2, 2003
    Messages:
    25,290
    Likes Received:
    2,078
    Location:
    In the mental ward of this forum
    Can others edit my Photos:
    Photos NOT OK to edit
    A lot depends on what you want to do with your final print. For your negatives, one should always use a fix with hardener to help protect the emulsion from scratches and whatnot. It's always desirable to do this for your film. For paper, it's sort of up to you.

    Will you want to tone your prints, now or later? If you think the answer is yes, use less than the manufacturer's recommendations on the hardener - or, none at all. There are several good books on toning out there, and it seems every author has his own opinion on how much hardener to use, if any. A hardener, as its name applies, will prevent additives from reaching the paper base, which can have a negative impact on the appearance of a toned print.

    I like making bromoil prints, and everything I read on the subject called for plain hypo (sodium thiosulphate), since, in a process similar to toning, the silver is to be bleached out of the print and a hardening agent will prevent that. So I keep sodium thiosulphate crystals around and make my own fix that way, when I am preparing prints exclusively for bromoil printmaking.

    If you have no intention of doing anything further to your prints, a fixer/hardener will protect your print's emulsion. Never a bad idea. :)

    Again, we shall await the inevitable descent of Mr. Know-it-All into this thread, for additional clarification and edification. :mrgreen:
     
  3. Hertz van Rental

    Hertz van Rental TPF Noob!

    Joined:
    Nov 8, 2004
    Messages:
    16,728
    Likes Received:
    45
    Location:
    Where am I now?
    Just for that, I won't. :hertz:
    Terri said it all anyway, so you don't want me throwing chemistry at you.
     
  4. Hertz van Rental

    Hertz van Rental TPF Noob!

    Joined:
    Nov 8, 2004
    Messages:
    16,728
    Likes Received:
    45
    Location:
    Where am I now?
    Oh go on then.

    Gelatine is a protein* and so it's chemistry is very complicated and difficult to understand as there is so much to understand.
    Hardening fixers contain chemicals like Boric acid, aluminium potassium sulphate or a chromium compound. They serve as pH buffers but have the added advantage of hardening the gelatine which process aids the drying process and improves mechanical strength and stability.
    Gelatine has a microscopic structure that is a bit like a sponge - it absorbs water easily and swells considerably. Hardening it turns the structure into more of a latice that resists swelling and so reduces absorbency. This is why certain post-processing manipulations require you not to harden - you need the emulsion to either swell a lot (Bromoil) or absorb chemicals easier (toning and such).
    If you want a more detailed explanation then I will have to start talking about the formation of cross-link bonds between amino acid spines.
    Do we really want to go there? :hertz:


    I only provide this in-depth technical information because it's like talking dirty to Terri - and we all know a moist Terri is a happy Terri.


    *Like egg white, which was used in early emulsions (before gelatine) - albumen prints.
     
  5. terri

    terri Administrator Staff Member Supporting Member

    Joined:
    Sep 2, 2003
    Messages:
    25,290
    Likes Received:
    2,078
    Location:
    In the mental ward of this forum
    Can others edit my Photos:
    Photos NOT OK to edit
    And gooey. :mrgreen: Let's not forget gooey.
     
  6. Hertz van Rental

    Hertz van Rental TPF Noob!

    Joined:
    Nov 8, 2004
    Messages:
    16,728
    Likes Received:
    45
    Location:
    Where am I now?
    A moist and gooey Terri? I can feel my emulsion hardening as we speak :lol:
     
  7. terri

    terri Administrator Staff Member Supporting Member

    Joined:
    Sep 2, 2003
    Messages:
    25,290
    Likes Received:
    2,078
    Location:
    In the mental ward of this forum
    Can others edit my Photos:
    Photos NOT OK to edit
    And you say chemistry is complicated. :sillysmi:
     
  8. Hertz van Rental

    Hertz van Rental TPF Noob!

    Joined:
    Nov 8, 2004
    Messages:
    16,728
    Likes Received:
    45
    Location:
    Where am I now?
    It is.
    Hardening is supposed to stop swelling but it just isn't working.
    I'm going to have to get you into the lab for some tests.
     
  9. terri

    terri Administrator Staff Member Supporting Member

    Joined:
    Sep 2, 2003
    Messages:
    25,290
    Likes Received:
    2,078
    Location:
    In the mental ward of this forum
    Can others edit my Photos:
    Photos NOT OK to edit
    I will defy such attempts.
     
  10. Hertz van Rental

    Hertz van Rental TPF Noob!

    Joined:
    Nov 8, 2004
    Messages:
    16,728
    Likes Received:
    45
    Location:
    Where am I now?
    Dang! That means I'll have to send Igor with the mad coachman to get you.
    Mad coachmen aren't cheap, you know.






    no consideration, some damsels
     
  11. terri

    terri Administrator Staff Member Supporting Member

    Joined:
    Sep 2, 2003
    Messages:
    25,290
    Likes Received:
    2,078
    Location:
    In the mental ward of this forum
    Can others edit my Photos:
    Photos NOT OK to edit
    But they can be bought....and re-bought, as needed. :)


    .....JamesD? Why haven't you returned to this thread? We did reply to your query, after all.



    Some people..... :roll:
     
  12. DocFrankenstein

    DocFrankenstein Clinically Insane?

    Joined:
    Apr 29, 2004
    Messages:
    1,646
    Likes Received:
    6
    :lmao: He probably doesn't want to interrupt. :lmao:

    BTT: Hertz - is hardener included in D76 (or D73)... whichever is for film?

    You've made me curious as to what bonds are formed. And what structures? Are those alpha helixes or beta plated sheets? Sulfur bonds?
     

Share This Page