Fun with Sodium Metaborate?

Discussion in 'B&W: Film, Paper, Chemistry' started by horacekenneth, Dec 5, 2012.

  1. horacekenneth

    horacekenneth Member

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    I've got almost a whole thing of Sodium Metaborate from trying Barry Thornton's two-bath method a couple months ago. I couldn't see any differences and I ended up ruining a whole roll so I gave up. (I've since found out I have a problematic patterson tank) Anyways, what can I do with it? Anything fun or interesting to do in a darkroom with sodium metaborate?
     
  2. Photo Engineer

    Photo Engineer Subscriber

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  3. Ian Grant

    Ian Grant Subscriber

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    Don't waste it, availablity is getting more difficult, although it can be made in situ in a developer from Borax and Sodium Hydroxide.

    Ian
     
  4. albada

    albada Subscriber

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    There are two kinds of sodium metaborate. Do you know if you have 4-mol (dihydrate) or 8-mol (tetrahydrate)?
    If it's 8-mol, I'll buy some from you. I'm designing developers using sodium metaborate, and I'd like to test them with both kinds.

    Anyway, there are a number of other developers you can mix using it.

    Mark Overton
     
  5. RidingWaves

    RidingWaves Member

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    Make DK-50
     
  6. horacekenneth

    horacekenneth Member

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    Albada, I can't tell, it's just from the photo formulary, I'm sure you already have it.

    That slime sounds fun.

    DK-50? Tell me about it
     
  7. jochen

    jochen Member

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    Sodiummetaborate-tetrahydrate (x 4 H2O) and -octahydrate (x 8 H20) are in fact the same. The formula for the first is NaBO2 x 4 H2O and for the second Na2B2O4 x 8 H2O which is the double of the first. You can see a good data sheet on the website of 20 Mule Team Borax (www.borax.com). Also on the market is the dry (sicc.) version without crystal water, but "Kodalk" was the hydrate.
     
  8. Adrian Twiss

    Adrian Twiss Member

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    Don't tell me this is another chemical the Home Office have decided to restrict.
     
  9. Rudeofus

    Rudeofus Subscriber

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    This is, unfortunately incorrect, and if you do the research you will find that there is NaBO2 * 2 H2O, NaBO2 * 4 H2O, Na2B2O4 * 4 H2O and Na2B2O4 * 8 H2O

    The first and the third in this list are the tetrahydrate, the second and the fourth are both the octohydrate, and tetrahydrate and octohydrate are indeed different in water content.
     
  10. Photo Engineer

    Photo Engineer Subscriber

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    Actually, these are all the same chemical, but in different relationships and with different waters of hydration. With correct adjustment based on the Sodium content, you get the same results from all of them.

    In water, at the same Sodium molar content, they form the same ions.

    PE
     
  11. Robert Ley

    Robert Ley Subscriber

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    OP, What didn't you like about Thornton's Two Bath? I recently tried it and like it very much. I can now do two or more emulsions at the same time with time, temp and agitation not being that critical. I like the way my highlights don't blow out in contrasty light and the mix is easy and cheap as I have had all the chemicals for many years.
     
  12. RidingWaves

    RidingWaves Member

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    DK-50 is a old common formula that was for deep tank and "press" use so it times are very short for 1:0 and even 1:1, but it has a nice 'brilliance' and a very nice and pronounced grain effect. Works much better than the common wisdom would have you think. Lasts a Long time, is easy to make and cheap, especially if you have the Sodium Metaborate around.
     
  13. horacekenneth

    horacekenneth Member

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    That sounds really nice. Pronounced grain, lasts a long time. Yes please. I have a bottle of undiluted rodinal I'm working through very slowly, any idea how long that is supposed to last?
    Ever used DK-50 as a paper developer?

    Robert, I may not have used it for the right situation. And I probably didn't know what I was looking for anyways. Would you tell me some more about your experience with it? I guess it might be worth trying again, I'm still a novice at judging exposure and development factors.