TEA 85%

Discussion in 'B&W: Film, Paper, Chemistry' started by Harold33, Mar 5, 2012.

  1. Harold33

    Harold33 Member

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    I would like to try the PC-TEA formula, but Triethanolamine (TEA) is not very easy to find in France (where I am), at least for small quantities.
    I have found one on-line shop who sells "85% TEA" but my knowledge in chemical matters is too weak to understand if such a solution is suitable for a phenidone-ascorbic acid developer. Here is the composition:

    Triethanolamine >85%
    Diethanolamine <15%
    Monoethanolamine <0.2%


    Thank you for your help.
     
  2. Photo Engineer

    Photo Engineer Subscriber

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    This is what is called Photograde and is the common variety sold just about world-wide.

    I use it effectively in several formulas with no problem whatsoever.

    You will pay a huge premium for anything better than this.

    PE
     
  3. Harold33

    Harold33 Member

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    Actually, the price of 85% TEA is very low compared to "pure" grade (1:12).

    Thanks a lot !
     
  4. albada

    albada Member

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    You can buy 98% TEA from Mistral in the UK.

    If you buy the 85% kind, as I did, the pH might be too high, which will make the developer work faster and might produce more grain. We don't know if Pat Gainer's PC-TEA formula used 85% or 99% TEA. Also, TEA is very hygroscopic, meaning it absorbs water from air quickly. So keep the bottle capped except when using it. And you might consider transferring the TEA to a glass bottle so that the TEA can not absorb water through the plastic jar-wall.

    Mark Overton
     
  5. Harold33

    Harold33 Member

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    According to this: http://mistralni.co.uk/catalogue/product/9/TEA-Triethanolamine, Mistral sells only 85% TEA + 15% of water. With such a mixture, it's normal to get a change of pH.
     
  6. cdholden

    cdholden Member

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    I recently discussed this with someone in relation to shelf life of Pyro-510. I was told that since I had used 99% TEA instead of 85% it wouldn't oxidize as quickly, making it's shelf life last longer. The 85% would work, but my preference would be for longer shelf life. Your preference and/or availability may be different.
     
  7. Photo Engineer

    Photo Engineer Subscriber

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    Look at the data in the OP. The 15% is not water. It is a mix of other ethanol amines.

    I'm sure there is water present, but not the full 15%.

    PE
     
  8. albada

    albada Member

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    A line at the top of that page says ">98%", which I'll guess refers to what's in the TEA-portion of that "85% TEA".

    15% water is not a problem because you can remove it. Heat the beaker to 90C and the water will come out as steam. But be careful to keep the temperature below 99C because the flash-point of TEA is 99C and above that, TEA vapor can get onto the heater and ignite, causing a fire. Also, at 100C and above, the water might "bump" (suddenly boil) and splash hot TEA everywhere. I know Pat Gainer recommended heating TEA over 100C, but you should be aware of the dangers of doing that.

    Mark Overton
     
  9. Rudeofus

    Rudeofus Subscriber

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    If you are totally paranoid about this, Fototechnik Suvatlar in Hamburg/Germany sells 99% TEA. Here's the price list and contact details, unfortunately only in German, but chem names are quite international anyway. They ship at least within the EU AFAIK.
     
  10. Harold33

    Harold33 Member

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    Interesting link: are you sure it's 99ยจ% TEA ? purity is not specified in this price-list. You tried it ?

    I'm not paranoid (I hope I'm not), but I like to understand what I'm doing when I buy some unknown product on the internet.