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  1. #1

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    Mixing Mytol and other developers for longer shelf life?

    I'm going to mix Mytol, probably also FX-37.

    I got the impression that Mytol, like Xtol, doesn't have long shelf life and may loose its activity all of the sudden, without prior warning.

    I also got the impression that mixing developers with alcohol, instead of water, prolongs their shelf life.

    First, are my above assumptions correct?

    Second, how is it recommended to mix developers in alcohol? Which alcohol?

  2. #2

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    Alcohol is not a great all-purpose solvent for developers. For one thing, neither ascorbic acid or ascorbate is soluble in alcohol. You will find it useful for dissolving phenidone before adding that to a water-based solution.

    Glycol, glycerine and triethanolamine are more useful solvents - Google up the recipes for PC-TEA and Pyrocat-MC to get some ideas.

  3. #3

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    If you are scratch mixing then one way to extend life is to forget about making up stock solutions. Instead make things up to working strength when you need it. This works for many formulas. Some supposedly need to age in stock form.

  4. #4

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    As has been mentioned, glycols and TEA are a couple of solvents that often get used. You can find formulas for PC-TEA, PC-Glycol, and a few others here. That site once had a recipe for a PC-Glycol/Mytol hybrid, but it's no longer there. (It seems to have been replaced by "Instant Mytol.") I have some notes on it, but they're confusing; I think I must have miscopied something.

    Another approach is to use a very simple developer that you can mix from dry chemicals at time of use, such as this one (credit to LR Kalajainen, who posted this on Usenet):

    phenidone: 0.04g
    ascorbic acid: 4g
    sodium carbonate (monohydrate): 6g
    water to make: 1000ml

    I believe he originally posted this using teaspoon measurements, but I don't have the equivalents at hand. The trouble is that measuring such a small amount of phenidone is difficult (particularly when making less than 1000ml of working solution), so a stock solution of phenidone is a practical necessity. If you add the ascorbic acid to that stock solution, you're most of the way to PC-Glycol.

  5. #5

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    Quote Originally Posted by psvensson View Post
    Glycol, glycerine and triethanolamine are more useful solvents - Google up the recipes for PC-TEA and Pyrocat-MC to get some ideas.
    Thank you.
    I prefer stick to Mytol.

    Quote Originally Posted by Nick Zentena View Post
    If you are scratch mixing then one way to extend life is to forget about making up stock solutions. Instead make things up to working strength when you need it.
    Thank you.
    For working solution of Mytol, 100 ml, I'll need 0.015 gram Phenidone, which is impractical.

    Quote Originally Posted by srs5694 View Post
    Another approach is to use a very simple developer that you can mix from dry chemicals at time of use, such as this one (credit to LR Kalajainen, who posted this on Usenet):
    Thank you.
    I prefer stick to Mytol.

  6. #6

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    Quote Originally Posted by Joshua_G View Post
    Thank you.
    I prefer stick to Mytol.

    Thank you.
    I prefer stick to Mytol.
    Well, it seems you have all your answers already. But 0.015 g phenidone is an easily measured 1.5 ml of a 1% solution of phenidone in alcohol, which makes it quite feasible to mix Mytol from scratch. I already supplied you, in another thread, with a formula for an easily scratch-mixed developer that give results similar to Mytol (though you will have to figure out your own times).

    I make the phenidone solution using 91% solution isopropyl alcohol, but I think other alcohols will work just as well. It lasts a long time, at least a year, with minimal loss of activitity. I generally add some potassium metabisulfite. It doesn't really dissolve, but goes into suspension and, at least in theory, should bind some of the water and act as an antioxidant preservative. I don't know how much good it really does.

  7. #7

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    Quote Originally Posted by psvensson View Post
    Well, it seems you have all your answers already. But 0.015 g phenidone is an easily measured 1.5 ml of a 1% solution of phenidone in alcohol, which makes it quite feasible to mix Mytol from scratch. .
    Thank you very much, a very helpful suggestion. Probably this is the answer I was looking for.
    For 1% solution, what are the proportions between the Phenidone (in grams) and the 91% IPA (in liters).

    Quote Originally Posted by psvensson View Post
    I already supplied you, in another thread, with a formula for an easily scratch-mixed developer that give results similar to Mytol (though you will have to figure out your own times).
    Thank you. You mean:
    Quote Originally Posted by psvensson View Post
    For D400, I used to dissolve in 1l:

    2 tbsp sodium sulfite
    2 g ascorbic acid
    5 ml 1% solution of phenidone in alcohol

    and use immediately at 24 C, 13.5 min.
    You recommended it for D400, while I'm looking for a developer for various films, medium speed and high speed, convention and T-Grain.

  8. #8

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    Quote Originally Posted by Joshua_G View Post
    Thank you very much, a very helpful suggestion. Probably this is the answer I was looking for.
    For 1% solution, what are the proportions between the Phenidone (in grams) and the 91% IPA (in liters).
    By convention, a "1% solution" is 1g of solid dissolved in 100ml of liquid. I use small syringes to add, for instance, 1.5 ml of solution to the developer.

    Quote Originally Posted by Joshua_G View Post
    You recommended it for D400, while I'm looking for a developer for various films, medium speed and high speed, convention and T-Grain.
    That scratch-mix developer will most likely give you results that are indistinguishable from Mytol 1:1 on all those varieties of films. It gives fine grain, very good speed, and mediocre accutance. While I use a non-solvent developer (i.e. one that has much less sulfite) for D400 now, I still use this high-sulfite brew for D3200, because it gives good speed while keeping the grain small.

  9. #9

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    Quote Originally Posted by psvensson View Post
    While I use a non-solvent developer (i.e. one that has much less sulfite) for D400 now, I still use this high-sulfite brew for D3200, because it gives good speed while keeping the grain small.
    Thank you.
    What developer do you use for higher acutance?

  10. #10

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    Quote Originally Posted by Joshua_G View Post
    Thank you.
    What developer do you use for higher acutance?
    A variant of Patrick Gainer's MC-TEA:

    100 ml triethanolamine, on low heat on stove
    25g ascorbic acid
    6g metol

    add triethanolamine to 150ml when solids have dissolved, let cool

    For working solution, mix up right before use:

    1l water
    10 ml MC-TEA
    10g sodium sulfite (2 tsp)

    Delta 400 35mm 74F 12min.

    It gives extremely good accutance and fine grain. It's especially good for large enlargements, because the grain structure isn't mushy, like you'll get from a solvent developer. The only downside is that the film speed is low: D400 needs to be exposed at 160-200 with this developer, Tri-X at 125, and D3200 at 640(!). Needless to say, I don't use it for the last two films.

    It may be that doubling the amount of sulfite will increase the speed while maintaining its other great characteristics, but I have yet to investigate. For maximum convenience, you can make a single-solution developer by adding more TEA, perhaps 50ml, to the stock, and leaving out the sulfite. I expect that will exacerbate the speed loss, however.

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