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Thread: PC-TEA 1:100

  1. #11

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    My tests only showed that PC-TEA 1:100 is finer grained than PC-TEA 1:50.I kind of assumed Larry's developer would be similar to the PC-TEA 1:50 for grain.I wonder if anyone would care to comment on how the other Vit-C developers really compare to PC-TEA 1:50.

  2. #12
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    Quote Originally Posted by Alan Johnson
    My tests only showed that PC-TEA 1:100 is finer grained than PC-TEA 1:50.I kind of assumed Larry's developer would be similar to the PC-TEA 1:50 for grain.I wonder if anyone would care to comment on how the other Vit-C developers really compare to PC-TEA 1:50.
    In my opinion - the best vitamin C developer on the planet is XTOL or a variation of XTOL called MYTOL. Mytol uses sodium ascorbate instead of ascorbic acid and does contain sulfite. I have used it to push process 120 TRI-X to 1600 and make 16x20 prints that were wonderfully sharp and smooth with very little grain. The reason I do not use it for everything is that it doesn't have many of the properties of staining developers and it has a finite shelf life - maybe 6 months. It is not expensive to make and it is not very toxic.
    My photos are always without all that distracting color ...

  3. #13
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    Quote Originally Posted by fhovie
    In my opinion - the best vitamin C developer on the planet is XTOL or a variation of XTOL called MYTOL. Mytol uses sodium ascorbate instead of ascorbic acid and does contain sulfite. I have used it to push process 120 TRI-X to 1600 and make 16x20 prints that were wonderfully sharp and smooth with very little grain. The reason I do not use it for everything is that it doesn't have many of the properties of staining developers and it has a finite shelf life - maybe 6 months. It is not expensive to make and it is not very toxic.
    The difference between ascorbic acid and the ascorbate is a tiny bit of carbonate or bicarbonate or borax or Kodalk. It would be better if you did use ascorbic acid and baking soda in place of the ascorbate, as the ascorbate powder does not keep as well as the acid. Use 2.1 g ascorbic acid and 1 g baking soda for each 2.36 g sodium ascorbate. Mix them in a little water and let the fizzing subside before mixing with the rest of the ingrdients. You can use this with any formula calling for sodium ascorbate.

    In PC-TEA, the salt of ascorbic acid is of TEA, which I suppose makes it an analog of ammonium ascorbate. You will find that it too will make wonderfully sharp and smooth negatives and will have a much longer shelf life. You might try reducing the sulfite in the Mytol to see if it makes any difference. Most who formulate developers containing sulfite seem to take as a given that it will have 80 grams or more. In the case of ascorbate developers, you can go all the way to zero with no fear of staining. The next time you mix a batch, try using it before you add the sulfite, just for fun.
    Gadget Gainer

  4. #14
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    Pat,

    Can you remind me once more why ascorbate is to be preferred over ascorbic acid? Not sure I understand the rationale. If the acid keeps better, why not just use it instead of ascorbate in any formula that calls for it?

    Larry

  5. #15
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    Quote Originally Posted by Maine-iac
    Pat,

    Can you remind me once more why ascorbate is to be preferred over ascorbic acid? Not sure I understand the rationale. If the acid keeps better, why not just use it instead of ascorbate in any formula that calls for it?

    Larry
    In any of the developers that are, like Xtol, water solutions with developing agents, activator and preservative, and in my own sulfite free developers, whether you use ascorbate or ascorbic acid is immaterial in the working solution, since whatever base you are using as activator will provide whatever is needed to give the ascorbate part of sodium ascorbate when it is needed in the reaction. In water solution, the sodium and ascorbate parts of sodium ascorbate are pretty much free to behave the same as if you had put sodium hydroxide and ascorbic acid in the solution. I do not know why there are formulas calling for sodium ascorbate and formulas calling for ascorbic acid. The pH will certainly be different if you substitute one directly for the other, but if you make sodium ascorbate out of ascorbic acid and baking soda in the proper proportions, you will get sodium ascorbate and carbon dioxide. True, the CO2 in water is slightly acidic, which is why carbonated beverages tingle the tongue, but using a minimum of water and allowing most of the CO2 to escape (go flat) will make that not a serious hazard. If you used the right amount of sodium hydroxide, there would be no CO2 and the pH would be the same as if sodium ascorbate had been used. Many are loath to use NaOH, even though it was used for many things in house and shop by their parents and grandparents, of whom I am one.

    At any rate, the specification of sodium ascorbate is not written in stone. I can think of valid reasons for preferring the acid in split stock developers, as a low pH generally prolongs storage life.
    Gadget Gainer

  6. #16

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    The formula for MYTOL calls for sodium ascorbate. In principle, you could just substitute ascorbic acid and add enough base to make up for it (sodium metaborate in the case of MYTOL). My guess is that they use sodium ascorbate (which forms slightly alkaline solutions in water on its own) as the starting material so that less base will be needed, either for cost savings or because you would have a solubility problem for the metaborate.

    Sometime soon I plan coming up with a MYTOL-like formula that uses ascorbic acid directly instead of sodium ascorbate (without the need to pre-neutralize with NaOH or NaHCO3). I'll post my results.

  7. #17
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    Quote Originally Posted by gainer
    I do not know why there are formulas calling for sodium ascorbate and formulas calling for ascorbic acid. The pH will certainly be different if you substitute one directly for the other. . . At any rate, the specification of sodium ascorbate is not written in stone. I can think of valid reasons for preferring the acid in split stock developers, as a low pH generally prolongs storage life.
    Quote Originally Posted by Jordan
    My guess is that they use sodium ascorbate (which forms slightly alkaline solutions in water on its own) as the starting material so that less base will be needed, either for cost savings or because you would have a solubility problem for the metaborate.
    Thanks, both of you for the explanations. I think that since I've got my Phenidone/Ascorbic Acid/Metaborate formula working so well and giving me the kind of negs that almost print themselves, I'll forego the joys of experimenting with ascorbate. My 1/2 tsp. AA, 1 tsp. Kodalk, and 2.5 ml Phenidone stock is so easy and so consistent and so fine-grained and sharp that it's pretty hard to beat. With ACROS or Delta 100, I can substitute 1 tsp. of carbonate for the metaborate and shorten the development time from 91/2 minutes to 7 which I like better, with no visible increase in grain.

    Larry

  8. #18

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    Hi , Have you tryed the PC-TEA with one of the alcohols in place of the water? I Have plenty of Methanol out in the shop. I ask because I made up some of the "basic" PC-TEA formula and about an hours stirring didn't seem to dissolve all of the A/A in 170 deg TEA. I dislike using water in developers until I am ready to use the stuff since film developing around here sometimes gets rather sporatic. Dave

    Quote Originally Posted by gainer
    P.S.: This method leaves the stock solution much less colored. It also works with ascorbic acid, phenidone and glycol. It will not work as well for mixing TEA or glycol and hydroquinone as the same amount of hot water makes a paste with hydroquinone. Hydroquinone is very soluble in alcohol, so I plan to try using alcohol to do the same trick.

  9. #19
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    I haven't tried it recently. I don't think methanol gives the same protection against aerial oxidation, but I really don't know why. I'm fresh out of methanol. They will only sell one 12 oz bottle of it at a time, in the form of gasoline drier. Afraid I'll start a meth lab, I guess. I think they would call the cops if I tried to buy Pseudephedrine and methanol at the same time.

    The small amount of water that aids in the solution doesn't seem to have any effect on storage life. You could try the methanol, but it will still probably have to be heated somewhat, and for that I recommend a water bath. Methanol is much more volatile and combustible than either TEA or propylene glycol. Its octane rating is 100.

    According to the CRC handbook, ascorbic acid is very soluble in water, but only soluble in alcohol. Hydroquinone is the other way round.
    Gadget Gainer

  10. #20

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    Ok, well I may try it time permiting as I have plenty of the stuff left over from my racing days but you are probably right. There should be a bounty on dopers and all of their ilk, You know, turn their ears (or something else) and get a $1.00. Dave

    Quote Originally Posted by gainer
    I haven't tried it recently. I don't think methanol gives the same protection against aerial oxidation, but I really don't know why. I'm fresh out of methanol. They will only sell one 12 oz bottle of it at a time, in the form of gasoline drier. Afraid I'll start a meth lab, I guess. I think they would call the cops if I tried to buy Pseudephedrine and methanol at the same time.

    The small amount of water that aids in the solution doesn't seem to have any effect on storage life. You could try the methanol, but it will still probably have to be heated somewhat, and for that I recommend a water bath. Methanol is much more volatile and combustible than either TEA or propylene glycol. Its octane rating is 100.

    According to the CRC handbook, ascorbic acid is very soluble in water, but only soluble in alcohol. Hydroquinone is the other way round.

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