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Thread: Mytol Mixup

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    blackmelas's Avatar
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    Mytol Mixup

    I mixed some Mytol for the first time the other day from "The Darkroom Cookbook." I only had ascorbic acid on hand so I substituted per Anchell (p. 33) at a ratio 8.89gr Ascorbic acid to 10gr sodium ascorbate. Thus I used 10.7gr of ascorbic acid for the 12gr sodium ascorbate in the Mytol. A first test roll came out ok but a little flat.

    However today I read the following at at http://www.photosensitive.ca/vitC-devs.shtml for the same substitution in Mytol--"Sodium ascorbate can be generated from ascorbic acid as follows: 13 g of sodium ascorbate is replaced by 130 ml of a solution made by dissolving 88.9 g sodium bicarbonate and 42.5 g ascorbic acid in 1000 ml water (careful of fizzing -- allow it to complete). This solution goes off quickly. Take your 130 ml and dump the rest, or scale down accordingly."

    Which method is correct?
    Thanks,
    James

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    If you substitute ascorbic acid for sodium ascorbate, you must make an adjustment in pH by adding more alkali, or the developer becomes less active.

    Either way will work as long as the acid is neutralized.

    PE

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    What PE said. Or you could just adjust your development time. I usually use just phenidone + ascorbic acid + sulfite, trusting to the sulfite to neutralize the acid.

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    James -- You could have e-mailed me directly via my site; I would have been happy to answer your question.

    The others are correct. The numbers I posted on that page, in fact, are directly from the MYTOL recipe that appears in the formulas section here on APUG.

    You could also compensate for the use of the acid instead of the salt by adding more sodium metaborate in your Mytol mix, as PE mentions. I haven't determined how much extra metaborate is required -- perhaps I'll do that someday.

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    blackmelas's Avatar
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    Thanks to all for the explanation. Jordan, Sorry I didn't realize it was your site. Had I known I would have PM'd you directly. It looks as though I should just try again with the Mytol, this time with your ascorbic acid/sodium bicarbonate solution. It'll be better to compare results with XTOL and with others who use a standard Mytol mix. BTW you have some really beautiful photos on your site. I like your sense of composition.
    Many thanks,
    James

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    I think you will get better results if you directly use sodium ascorbate and don't try to make it from ascorbic acid. The presence of bicarbonate in the developer can throw off the final pH and thus affect the activity. Sodium ascorbate is often sold by places that sell health products since it is nonacidic and better tolerated in large doses as a vitamin.

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    James -- The sodium bicarbonate trick comes right from APUG, it's not my invention. It works (measure carefully!) but as Jerry says, using powdered sodium ascorbate would be more convenient and precise.

    Lately, when I want something like MYTOL, I use the "PC-Gly-TOL" that is also described on the page you linked to. It's more convenient than mixing up MYTOL.

    Thanks for your kind comments on my site!

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    Quote Originally Posted by Gerald Koch
    I think you will get better results if you directly use sodium ascorbate and don't try to make it from ascorbic acid. The presence of bicarbonate in the developer can throw off the final pH and thus affect the activity. Sodium ascorbate is often sold by places that sell health products since it is nonacidic and better tolerated in large doses as a vitamin.
    If you were assured of getting the same quality every time, yes. The acid keeps better than the salt. I think as a matter of fact that the accuracy required is such that a slight excess of the bicarbonate will change the developer pH very little. Bicarbonat has no water of hydration to contend with, and it is USP grade from the grocery store. Both it and the ascorbic acid are more stable than the ascorbate, and the person who only makes a liter or so a month might be better off. A pound of the ascorbate would make about 3 years worth of developer at that rate, if it would last that long.
    Gadget Gainer

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    I'm just glad someone is mixing some mytol, I have heard very little feedback on this formula. I hope you will post your results after using it for a while. 5 liters of Xtol is just too much for me to use most of the time, since I photograph and develop in spurts.


    Wayne

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    Quote Originally Posted by Wayne
    5 liters of Xtol is just too much for me to use most of the time, since I photograph and develop in spurts.
    FWIW, I'm nearing the end of my first 5 liters of XTOL; I'm down to about 500ml. It's now slightly over a year old and still working fine, although I'm at the point where I do wonder every time I open the tank whether I'll see actual images on the film....

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