Shelf Life Of Phenidone

Discussion in 'B&W: Film, Paper, Chemistry' started by Snapshot, Nov 26, 2007.

  1. Snapshot

    Snapshot Member

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    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?
     
  2. Photo Engineer

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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
     
  3. Rlibersky

    Rlibersky Subscriber

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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. Snapshot

    Snapshot Member

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    Thanke PE. So, I guess as long as I keep it in poweder form, phenidone should not lose much potency.
     
  5. Snapshot

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    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.
     
  6. Photo Engineer

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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
     
  7. srs5694

    srs5694 Member

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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. Photo Engineer

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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. Tom Hoskinson

    Tom Hoskinson Member

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    Long Lived Phenidone Stock Solution

    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.
     
  10. Bruce Osgood

    Bruce Osgood Membership Council Council

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    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?
     
  11. Tom Hoskinson

    Tom Hoskinson Member

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    Bruce, my Phenidone Stock Solution contains .03 grams Phenidone per ml

    7.5 grams of Phenidone dissolved in 250ml of Propylene Glycol.

    Thus: 33.33ml of my stock concentrate = 1 gram of Phenidone

    Most of my recipes require less than 0.5 gram of Phenidone.
     
  12. srs5694

    srs5694 Member

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    Concerning glycol stock solutions, this is the basis of Pat Gainer's PC-Glycol. This uses 0.25g of phenidone and 10g of ascorbic acid in enough propylene glycol to make 100ml. This "A" solution can be combined with various "B" solutions. In terms of phenidone concentration, this is obviously much less than what Tom is using, but it's still concentrated enough that you don't need a whole lot of stock solution to develop a roll of film. With a 15% sodium carbonate solution for the "B" stock, PC-Glycol can be used at 1+1+48 for normal development times (5-10 minutes for most films). This is 5ml of each stock solution plus water to make 250ml of working-strength developer. If you want to create a solution with which to make larger quantities of other developers (DS-10, Mytol, etc.), going with a higher concentration of phenidone alone makes more sense to me.
     
  13. Photo Engineer

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    I don't like working with syrups or thick solutions. This is why I design solutions to be easily poured and very stable and the same time. It can be done.

    PE
     
  14. Snapshot

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    I'm concerned that storing phenidone in chemical solutions will have an impact on development, as you have to add this solution along with the phenidone. I am presuming that glycol has no adverse effects on most developer formulas, since this seems to be a popular way of storing phenidone.
     
  15. Tom Hoskinson

    Tom Hoskinson Member

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    My Propylene Glycol stock solutions (like my Phenidone stock solution) are low viscosity and thus pour quite easily.

    Triethanolamine based stock solutions, on the other hand, are quite viscous and difficult to pour. However, they can easily be thinned with Propylene Glycol. Pyrocat - MC is a good example.
     
  16. Photo Engineer

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    Tom;

    I have plenty of PG and EG here and work with it. I know that the viscosity of both are relatively low, but still enough to make me work with weight/weight measures instead of wt/volume when putting Phenidones into PG. Pouring it out is still a minor pain.

    In fact, in the darkroom, with emulsions, you learn real quick that wt/wt is a better method with liquid emulsions due to the varying viscosities of the gelatins.

    Anyhow, it is a learned habit of mine for accuracy that I don't wish to impress on anyone else. I was just expressing my opinion. In any event, a 1:9 dilution is good enough for me for most situations. This will probably be the case for the High Acutance developer I'm working on right now. And I always work for very high stability in stock and working solutions. You don't need A+B solutions or concentrated organic solvents like PG to achieve this.

    PE
     
  17. Tom Hoskinson

    Tom Hoskinson Member

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    Thanks for the additional information, PE
     
  18. Tom Hoskinson

    Tom Hoskinson Member

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    Regarding the use of Propylene Glycol as a phenidone solvent, I have seen no adverse impact on my negatives - or on my Fiber prints, either (I use print developer concentrates dissolved in a solution of Propylene Glycol, Triethanolamine and water). Propylene Glycol, Triethanolamine and Water are fully miscible.