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Thread: Formula?

  1. #11
    gainer's Avatar
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    I never did say what the original formula was. It was in my article on The Role of Antifreeze in Photographic Science in Mar/Apr Photo Techniques. That recipe called for 10 grams of hydroquinone and 0.25 grams of phenidone dissolved in propylene glycol to make 100 ml. It is necessary to heat the mixture condiserably to get it to dissolve. Once dissolved it does not precipitate. There is no sulfite, bisulfite or bromide in it. It is used with the same B solution as Pyrocat-HD, to which bromide may be added if fogging is a problem. This is not, IIRC, the same formula that Tom Hoskinson posted. The glycol served the function of preservative without contributing any activity, and in fact inhibiting activity until water is added. This allows experimenting with sulfite free developers of many kinds. If sulfite is desired, it is easily added to the B solution.
    Gadget Gainer

  2. #12
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    Thanks Pat, everything I can gather will make the experience more fun and rewarding. Maybe one day I'll know enough to develop an interesting developer. (pun might be intended- I'll never tell!)
    Gary Beasley

  3. #13

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    glbeas:

    The recipe I posted simply replaced the 5 grams of catechol in Pyrocat-HD with 5 grams of hydroquinone. The amount of phenidone remained at 0.2 grams. Bisulfite and potassium bromide were eliminated from the "A" solution (bromide or benzotriazole to be added later as required). I dissolved the phenidone and hydroquinone in about 30 ml of methanol at room temperature. I then added ethylene glycol to make 100 ml total.

    The "B" solution remained as 100 grams of potassium carbonate dissolved in water to make 125 ml total.

    As Pat Gainer has said, propylene glycol works just as well (in the inert solvent/preservative role) as ethylene glycol and is less toxic.

    Friday, I used a variation of Pat Gainer's method of heating propylene glycol to mix some percentage solutions (pyrogallol, catechol and phenidone) for PPPD testing. I used a hot plate and magnetic stirrer plus a digital thermometer and found that these developing reagents dissolved around 140 to 160 degrees F.

    Metol doesn't dissolve in any of the alcohols/glycols. I expect that Glycin won't either.
    Tom Hoskinson
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  4. #14
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    If you do not specifically need a staining developer, the PQ-Glycol solution may be diluted with an equal amount of triethanolamine. Dilute the result for use 1+25 and add a pinch (very unscientific, I know) of sulfite. Development time for FP4+ will be about 7 minutes at 70 F with intermittent agitation. The amount of sulfite is not critical, so for "pinch" you can substitute 1/4 tsp per liter. Just enough to activate the synergism between phenidone and hydroquinone.
    See what can happen when you spend too much time in the darkroom and not enough taking pictures?
    Gadget Gainer

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