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Thread: Life of Amidol

  1. #11
    gainer's Avatar
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    By now, someone should have tried it. I don't know if amidol is sufficiently soluble in any of the glycols to be useful, but if it is, such a solution should last a long time. The bit of amidol I had oxidized begore I began playing with glycol, and I don't use enough to spend the money on more.
    Gadget Gainer

  2. #12
    fhovie's Avatar
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    I guess what I was looking for was the true nature of the demise of the Amidol solution. I know that many have reported an almost endless capaicty but that in a tray it goes dead in 24 hours of exposure to air. Here I have denied air but a few hours of exposure and it seems to hold up at least a few weeks which reduces the cost of a tray of developer considerably (per print). The brew I use is this ...

    30g Sodium Sulfite
    3g Citric Acid
    11g Amidol
    .2g Potassium Bromide
    per liter water

    Could I expect even more shelf life? Is it the water that ruins the Amidol?

  3. #13
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    I only make working solution ... As with all my chemicals, I make up kits once a month or so by pre-weighing dry chemicals into little plastic packets and heat sealing them into little kits so when I need a solution, I grab the scizzors and mix up a fresh solution ready to use. I believe the shelf life of most dry powders is very good. Amidol is the second most expensive chemical I use; Silver Nitrate being the first.


    Quote Originally Posted by jdef
    Frank, I think that somebody should make the distinction between stock solution and working solution, so I'll volunteer. A glycol-based stock solution would undoubtedly have a very long shelf life, but once the stock is made into a working solution, we're right back in the same boat, longevity-wise. I think that denying your working solution oxygen is about the best that can be done to extend its useful life, although there might formulaeic tricks that would further that cause. I usually just hang around and wait for the smart guys to figure that kind of stuff out.

    Jay

  4. #14

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    Quote Originally Posted by fhovie
    I only make working solution ... As with all my chemicals, I make up kits once a month or so by pre-weighing dry chemicals into little plastic packets and heat sealing them into little kits so when I need a solution, I grab the scizzors and mix up a fresh solution ready to use. I believe the shelf life of most dry powders is very good. Amidol is the second most expensive chemical I use; Silver Nitrate being the first.
    Yes indeed, the shelf life of dry Amidol is very long (many years according to reports).

    My own experiments with Amidol dissolved in Propylene Glycol have been very successful. The advantage I see in this method is that I minimize the safety problems associated with handling dry amidol powder. I mix up enough stock concentrate for several printing sessions at one time under a vented chemical hood.
    Tom Hoskinson
    ______________________________

    Everything is analog - even digital :D

  5. #15
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    If the caps are not liquid tight, then they are not air tight. I cut a disc of neoprene to make a good air-tight seal for the cap when I re-use old chemical containers.

    You can buy zillions of glass marbles at your local toy shop cheaply - but be aware, it takes a lot more marbles that you would think! I've had stock ID-11 still 100% OK after 10 months by topping the bottle (reused Ilford MG developer bottle) up with marbles.

    I've tried the accordian bottles but you can only compress by about 25% and the necks are quite wide so I'm not sure how well they perform in practice without replacing the air with another gas; besides, I've never been able to get a decent tune out of one...

    Cheeers, Bob.

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