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  1. #21

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    The first bottle of Phenidone I bought in 1983 was from Ilford and it was plastic. It is still fine.
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  2. #22
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    Quote Originally Posted by Kirk Keyes View Post
    The first bottle of Phenidone I bought in 1983 was from Ilford and it was plastic. It is still fine.
    There's a lot of disinformation about Phenidone and it's keeping properties. Whether as a compond or as a made up solution the keeping properties are excellent, but in solution it outlasts Metol by a huge factor.

    Ilford's Autophen developer, also known as the Axford Kendall photo-finishing developer had an indefinite life replenished. It was a PQ variant of Ilfords ID-11 (D76) but unlkke the MQ formula wasn't prone to sudden death due to bromide etc build up.

    Ian

  3. #23

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    All I can say is that I have a plastic jar of black tar that once was phenidone. A glass jar of phenidone that is far older remains fine. The high humidity and temperatures in Florida may be the difference.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  4. #24

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    This is interesting. If Phenidone keeps well in solution as Ian says, why do formulas like POTA have a reputation for being extremely short lived?

  5. #25

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    Quote Originally Posted by Michael R 1974 View Post
    This is interesting. If Phenidone keeps well in solution as Ian says, why do formulas like POTA have a reputation for being extremely short lived?
    Phenidone hydrolyses easily in solution particularly alkaline solution. There are at least two products formed a red form and a blue form both free radicals. The presence of reducing agents such as other developing agents like hydroquinone help stabilise it. Presence of the red form is used to quantitatively measure the amount of phenidone in developers. There is an extended discussion in Mason.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  6. #26
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    Due to the instability of Phenidone in alkali, Kodak was converting or had converted all developers to Dimezoen or better still to Dimezone-S to avoid hydrolysis.

    PE

  7. #27
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    Quote Originally Posted by Michael R 1974 View Post
    This is interesting. If Phenidone keeps well in solution as Ian says, why do formulas like POTA have a reputation for being extremely short lived?
    It's relative PQ solutions tend to keep much longer than MQ and there do appear to be big differences in keeping properties of Phenidone synthesised in the US compared to the UK.

    I can only speak from experience. I regularly use Phenidone developers made up from raw chemistry up to 2 or 3 years before with no issues the only caveat is stored in full bottle for most of the time.

    Ian

  8. #28

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    The hydrolysis of phenidone is pH dependent. The higher the pH of the solution the faster the rate of hydrolysis. So low pH developers will keep longerr than those with a higher pH.

    If you have ever made up the POTA developer you will notice that the solution quickly becomes pink. In the early steps of the hydrolysis the reaction IS reversible.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  9. #29

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    Quote Originally Posted by Gerald C Koch View Post
    All I can say is that I have a plastic jar of black tar that once was phenidone. A glass jar of phenidone that is far older remains fine. The high humidity and temperatures in Florida may be the difference.
    Most certainly environmental conditions can have a huge effect on chemical storage. I live in the Pacific Northwest - much liwer humidity and temp conditions than Florida.

    I was only trying to show it can last a long time.
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

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