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  1. #11
    Photo Engineer's Avatar
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    Quote Originally Posted by Tom Hoskinson View Post
    Yes, TEA and DEA are best at gettering water and oxygen
    Tom;

    Both DEA and TEA are rather inert to oxygen chemically. They are strongly alkaline and very mildly chelating. TEA is used as a base in developers.

    DEA is a mild silver halide solvent.

    PE

  2. #12
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    You can do searches for Sodium Hexametaphosphate and buy it in a lifetime supply on Ebay. 1 lb. is $8 3 lb. is $13 10 lb. is $27. I have to use it out in the desert where I live or I get calcite bits on my negs after they dry.
    He is no fool who gives what he cannot keep..to gain that which he cannot lose. Jim Elliot, 1949

    http://tonopahpictures.0catch.com

  3. #13

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    Quote Originally Posted by Photo Engineer View Post
    Tom;

    Both DEA and TEA are rather inert to oxygen chemically. They are strongly alkaline and very mildly chelating. TEA is used as a base in developers.

    DEA is a mild silver halide solvent.

    PE
    You are right on all counts, PE.

    I goofed, sorry!
    Tom Hoskinson
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    Everything is analog - even digital :D

  4. #14
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    Tom;

    Maybe I should point out that you had reason for your answer. Both TEA and DEA react with air, but not oxygen (readily). It is the Carbon Dioxide that they react with, gradually forming the carbonate salt.

    This will drag the pH more acidic.

    PE

  5. #15

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    Quote Originally Posted by Photo Engineer View Post
    Tom;

    Maybe I should point out that you had reason for your answer. Both TEA and DEA react with air, but not oxygen (readily). It is the Carbon Dioxide that they react with, gradually forming the carbonate salt.

    This will drag the pH more acidic.

    PE
    Thanks very much for the clarification, PE
    Tom Hoskinson
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  6. #16

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    See 'Complex Phosphates' here:
    www.chemistry.co.nz/deterg_inorganic.htm
    It may be tripolyphosphate has sesquicarbonate added to reduce alkalinity. I can see no obvious reason why tripolyphosphate should not work provided it does not affect the pH.

  7. #17
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    Quote Originally Posted by Photo Engineer View Post
    Tom;

    Maybe I should point out that you had reason for your answer. Both TEA and DEA react with air, but not oxygen (readily). It is the Carbon Dioxide that they react with, gradually forming the carbonate salt.

    This will drag the pH more acidic.

    PE
    That explains why a working solution of PC-TEA or the like, made with my hard well water and left standing in an open pitcher, will turn cloudy as would a developer like Dektol. I'm assuming that the TEA makes a carbonate out of CO2 from air which it hands over to the Mg and Ca in the well water making limestone as the cloudy stuff. OTH, even a glass of well water standing open should become cloudy. Anyway, it's very good drinking water from 110 feet down. If I ever get a water softener, I shall put a tap between the well and the softener for drink.
    Gadget Gainer

  8. #18
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    P.S.
    110 feet down is still about 800 feet above sea level where I live.
    Gadget Gainer

  9. #19
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    Quote Originally Posted by gainer View Post
    P.S.
    110 feet down is still about 800 feet above sea level where I live.
    Patrick;

    Get a high capacity Reverse Osmosis unit. It will turn out deionized water and concentrate the salts in another output.

    Some will produce many gallons per day.

    I meant to add that my wife and I both grew up in the same area at about the same altitude.

    PE
    Last edited by Photo Engineer; 03-05-2008 at 08:42 AM. Click to view previous post history.

  10. #20
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    Just a general note.

    Our atmosphere is acidic and oxidizing due to the CO2 and O2 in it. Any alkaline solution left out in the open will react with CO2 and form a salt while decreasing in pH. Any reducing solution left out in the air will oxidize. This goes for the solids as well as the solutions I might add.

    Therefore, developer, which is an alkaline solution of reductants goes bad when exposed to air. The CO2 makes it more acidic and the O2 oxidizes the reducing agents including HQ, Metol, Phenidone, Glycin and etc.

    PE

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