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  1. #1
    Snapshot's Avatar
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    Shelf Life Of Phenidone

    Hi All,

    I have purchased a quantity of phenidone, 25 grams to be exact, to use in home mixed formulas. However, I understand that phenidone can lose potency over time and I doubt that I can use 25 grams of it in a reasonable time. Does anyone know the shelf life of phenidone and any way to store it for the long haul?
    "The secret to life is to keep your mind full and your bowels empty. Unfortunately, the converse is true for most people."

  2. #2
    Photo Engineer's Avatar
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    The solid powder is pretty stable, but it loses strength in alkaline solutions.

    Dimezone is better for keeping all around, and Dimezone-S is even better.

    PE

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    Rlibersky's Avatar
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    Excuse the ignorence and I know I could look it up, I thought this would answer it in one spot. What is Dimezone and Dimezone-S

    Randy

  4. #4
    Snapshot's Avatar
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    Quote Originally Posted by Photo Engineer View Post
    The solid powder is pretty stable, but it loses strength in alkaline solutions.

    Dimezone is better for keeping all around, and Dimezone-S is even better.

    PE
    Thanke PE. So, I guess as long as I keep it in poweder form, phenidone should not lose much potency.
    "The secret to life is to keep your mind full and your bowels empty. Unfortunately, the converse is true for most people."

  5. #5
    Snapshot's Avatar
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    Quote Originally Posted by Rlibersky View Post
    Excuse the ignorence and I know I could look it up, I thought this would answer it in one spot. What is Dimezone and Dimezone-S

    Randy
    Dimezone is an analog of phenidone. It is supposed to have better solubility in water and is more stable in solution. However, you'll get better answers shortly.
    "The secret to life is to keep your mind full and your bowels empty. Unfortunately, the converse is true for most people."

  6. #6
    Photo Engineer's Avatar
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    Dimezone is Dimethyl phenidone, and Dimezone-S (MOP or HMMP) is Hydroxymethy, methy Phenidone.

    I'm sure that didn't help at all.

    PE

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    As a practical matter, you can use phenidone and Dimezone S interchangeably, although some sources say you need a slight adjustment in quantity (more Dimezone S, IIRC) to get equal activity. Most home-brew formulas that use one of these ingredients specify phenidone, presumably because it's less expensive and easier to acquire. A few formulas (notably some of Ryuji Suzuki's) specify Dimezone S because of its superior keeping qualities in solution. My understanding is that most commercial "phenidone-based" developers, such as XTOL, actually use Dimezone S; however, this is just "common knowledge" that's been passed around, so it could easily be inaccurate.

    Personally, I've only used Dimezone S, not phenidone, so I can't comment on subtle differences between the two. I've never had problems using Dimezone S in 1:1 substitution in formulas that call for phenidone, but in practice I might have ended up with slightly lowered activity level if the claim of a need for more Dimezone S is accurate. If so the effect wasn't big enough to cause me any real problems.

  8. #8
    Photo Engineer's Avatar
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    We used HMMP or MOP as we called it (Dimezone-S in the outside world) at Kodak almost exclusively. It is the most stable and most soluable of all of the phenidone family. It was used in PR-10 print material pods and a few other products as well.

    We sometimes used it as an incorporated developer in coatings, but when dry, Phenidone itself was just as good.

    PE

  9. #9

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    Long Lived Phenidone Stock Solution

    Quote Originally Posted by Snapshot View Post
    Hi All,

    I have purchased a quantity of phenidone, 25 grams to be exact, to use in home mixed formulas. However, I understand that phenidone can lose potency over time and I doubt that I can use 25 grams of it in a reasonable time. Does anyone know the shelf life of phenidone and any way to store it for the long haul?
    I've posted this on APUG several times before: Phenidone is readily soluble in Propylene Glycol. I have a Phenidone/Glycol stock solution in my darkroom that is over 3 years old and is still fully active.
    Tom Hoskinson
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  10. #10
    Bruce Osgood's Avatar
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    Quote Originally Posted by Tom Hoskinson View Post
    I've posted this on APUG several times before: Phenidone is readily soluble in Propylene Glycol. I have a Phenidone/Glycol stock solution in my darkroom that is over 3 years old and is still fully active.

    Tom,
    I recall seeing this post but can't find it anymore.

    How rich is your Glycol solution? If you are dealing in per-cent solution how do you equate to X amount of Phenidone in a formula? I'm not sure that's clear... let me try again:

    How many mL of your Phenidone Glycol do you use to equal 1g Phen in a formula?
    Bruce Osgood
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    "Print with #3.5 and burn with #1.5." B.J. Confucius
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