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  1. #11

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    Quote Originally Posted by Bruce Osgood View Post
    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, 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.
    Tom Hoskinson
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  2. #12

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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.

  3. #13
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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

  4. #14
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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.
    "The secret to life is to keep your mind full and your bowels empty. Unfortunately, the converse is true for most people."

  5. #15

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    Quote Originally Posted by Photo Engineer View Post
    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
    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.
    Tom Hoskinson
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  6. #16
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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

  7. #17

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    Quote Originally Posted by Photo Engineer View Post
    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
    Thanks for the additional information, PE
    Tom Hoskinson
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  8. #18

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    Quote Originally Posted by Snapshot View Post
    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.
    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.
    Tom Hoskinson
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