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  1. #1

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    why TEA in DS-14

    I'm considering trying DS-14, as I have a Nova processor and like the idea of a developer that can be replenished. However, I'm wondering what the purpose of TEA in this formula is. Is it doing something that other more regular developer components can't?

  2. #2
    Snapshot's Avatar
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    It's my understanding that it is used as a chelating agent, which can extend the shelf life of the stock solution. In addition, TEA can be used as a buffering agent.
    "The secret to life is to keep your mind full and your bowels empty. Unfortunately, the converse is true for most people."

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    Quote Originally Posted by Snapshot View Post
    It's my understanding that it is used as a chelating agent, which can extend the shelf life of the stock solution. In addition, TEA can be used as a buffering agent.
    TEA is not a chelating agent, it is a viscous liquid alkali that can be used as a buffering agent. The (iron) chelating reagent in DS-14 is Salycilic Acid.
    Tom Hoskinson
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  4. #4
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    Quote Originally Posted by Tom Hoskinson View Post
    TEA is not a chelating agent, it is a viscous liquid alkali that can be used as a buffering agent. The (iron) chelating reagent in DS-14 is Salycilic Acid.
    To quote from the Silvergrain website...

    At that time, my preferred chelating agent was triethanolamine and diethanolamine. These are more effective than those above, and they can be used as a buffering agent, but their efficacy in stabilizing developers was unpredictable depending on the formula, until much later time.

    Here is where the quote can be found....

    http://wiki.silvergrain.org/wiki/Ascorbate_Developers

    It seems that Ryuji thought it had useful chelating properties.
    Last edited by Snapshot; 02-19-2008 at 11:44 AM. Click to view previous post history.
    "The secret to life is to keep your mind full and your bowels empty. Unfortunately, the converse is true for most people."

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    Triethanolamine is an accelerator

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    Snapshot's Avatar
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    At 5ml per litre of DS-14 solution, TEA isn't much of an accelerator.
    "The secret to life is to keep your mind full and your bowels empty. Unfortunately, the converse is true for most people."

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    Quote Originally Posted by Snapshot View Post
    At 5ml per litre of DS-14 solution, TEA isn't much of an accelerator.
    Suzuki on Salicylate:

    http://wiki.silvergrain.org/wiki/Ascorbate_Developers
    “In the summer of 2003, I found a relatively recent research that salicylic acid is an effective iron chelator, and this form of iron is inactive as the oxidation catalyst. I compounded a few ascorbate developers incorporating salicylic acid, and observed how long the solutions lasted. The result was very promising.”


    TEA 99% (a tertiary amine used to react with acidic compounds to form salts) – a weak base that can be used as a pH adjustor.

    http://www.sciencelab.com/xMSDS-Triethanolamine-9927306

    TEA Physical state and appearance: Liquid. (Clear viscous liquid.)
    Odor: Ammoniacal. (Slight.)
    Taste: Not available.
    Molecular Weight: 149.19 g/mole
    Color: Colorless to light yellow.
    pH (1% soln/water): 10 [Basic.]


    Haist on Triethanolamine (pages 248-250 of Modern Photographic Processing, Volume 1).

    “Triethanolamine was suggested in 1937 by Maurice Ney for fine-grain development. Triethanolamine is weakly alkaline, does not attack gelatin or film base and is odorless and non-irritating (unlike acetone). The developer containing it was said not to lose its alkalinity…”
    Tom Hoskinson
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  8. #8
    Snapshot's Avatar
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    Throw all the data sheets and Haist quotes you want as I'm not arguing that TEA isn't used as an accelerator (nor am I'm arguing salicylic acid isn't being used as a chelator). However, I am under the belief that Ryuji included TEA in DS-14 to act as a chelating agent. Salicylic acid is included as an iron chelating agent but it doesn't preclude other agents being added, unless there is some law that I am unaware of that precludes such.

    The question that was posed is why TEA included in DS-14, a Ryuji formulation. I'm very doubtful it was intended an alkali accelerator as 5ml not enough to provide this action. That is why there is 30 grams of carbonate. It very possible TEA has been included as a buffering agent. However, with DS-14 having a pH 10.4 I'm a little doubful of this. Regardless, Ryuji has clearly stated that he used TEA as a chelating agent. Anyway, unless someone knows his mind this isn't going to get settled.
    Last edited by Snapshot; 02-19-2008 at 02:25 PM. Click to view previous post history.
    "The secret to life is to keep your mind full and your bowels empty. Unfortunately, the converse is true for most people."

  9. #9
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    Take what Ruyuji writes with pinch of salt. There are many errors on his Silvergrain website, and even when others point him to the correct original (primary) sources he still perpetuates his mistakes.

    Ian

  10. #10
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    Quote Originally Posted by Ian Grant View Post
    Take what Ruyuji writes with pinch of salt. There are many errors on his Silvergrain website, and even when others point him to the correct original (primary) sources he still perpetuates his mistakes.

    Ian
    Fair enough. I'm not trying to redefine what the role of TEA plays in photographic chemistry, just trying to answer the OP question. Heck, I use TEA as an accelerator in some developer formulas.
    "The secret to life is to keep your mind full and your bowels empty. Unfortunately, the converse is true for most people."

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