Mytol Mixup

Discussion in 'B&W: Film, Paper, Chemistry' started by blackmelas, May 22, 2006.

  1. blackmelas

    blackmelas Subscriber

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    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
     
  2. Photo Engineer

    Photo Engineer Subscriber

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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
     
  3. psvensson

    psvensson Member

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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.
     
  4. Jordan

    Jordan Member

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

    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.
     
  5. blackmelas

    blackmelas Subscriber

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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
     
  6. Gerald Koch

    Gerald Koch Member

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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.
     
  7. Jordan

    Jordan Member

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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!
     
  8. gainer

    gainer Subscriber

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    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.
     
  9. Wayne

    Wayne Subscriber

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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
     
  10. srs5694

    srs5694 Member

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    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....
     
  11. blackmelas

    blackmelas Subscriber

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    Thanks again for all the info. Maybe now I can go back to unblinking eye and read Mr. Gainer's articles with 'new eyes.' I see now that is a little more complex than following simple recipes in the Darkroom Cookbook. I'm probably going to be using a liter per month or less and was looking to Mytol as a good general and push processing developer that required relatively few, powdered(easier to ship), and non-hazardous chemicals. Obviously I'm a newbe at the homebrewed darkroom chemistry and I'm still working to cobble together EU and local Greek suppliers for various chems. You all are a great help in this journey!
    Thanks,
    James
     
  12. srs5694

    srs5694 Member

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    I found it was simpler than I expected it to be, at least when following a known-working recipe like PC-Glycol, DS-14, E-72, etc. (just to name a few I've used). There are potential pitfalls, such as the bad substitutions information being discussed in this thread, but the formulas I've tried have all worked. Even if you do something wrong, there's a good chance that the developer will work, just not in quite the way it was intended to work.
     
  13. blackmelas

    blackmelas Subscriber

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    Yes, you're right. Its wasn't such a big error. The negs I developed in my acidic Mytol were printable at grade 4 or 4 1/2. I'll remix with the Ascorbic Acid/Sodium Bicarbonate solution to see if I can bring them in at grade 2 or 3. Then when I'm finished with the Dektol that I have, I'll try to brew some E-72.
    James
     
  14. Gerald Koch

    Gerald Koch Member

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    I would not recommend E-72 as it is a rough copy of D-72 made on a couple of general assumptions. The first is that you can always substitute Phenidone for Metol and the second is a similar assumption for substituting ascorbic acid for hydroquinone. No attempt was made to come up with a balanced formula or provide good keeping properties. Does it develop prints -- yes. Is it a good print developer -- no. There are better formulas. I would suggest DS-14 or DS-15. A lot of thought and development was put into these two formulas and they produce good results and have good shelf life.
     
  15. srs5694

    srs5694 Member

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    Concerning E-72, DS-14, and DS-15: I've got prints of the same negative made with the metol variant of E-72 and with DS-14. I made these explicitly for comparison purposes and for comparison to DS-14 as it ages. Aside from print-specific flaws (dust specks in particular places, etc.), I can't tell the two apart. Maybe I'm just not observant enough, or maybe the paper I used (Agfa MCP310 RC) just happens to respond very similarly to the two developers.

    That said, I prefer DS-14, the reason being its excellent keeping qualities and replenishability. As described on its Web page, DS-14 can be replenished with itself minus potassium bromide. After each printing session, I pour my DS-14 back into the bottle and top it off with the replenisher. The first time I did this, I stopped after using 1 liter of replenisher because the solution was getting darker and cloudy. I then mixed another fresh batch of DS-14 and am now nearly done with the first liter of replenisher for it. (I mixed both about three months ago.) I did a comparison test print when I'd used about 600ml of the replenisher and saw no difference from the test print I made with the fresh developer. I'll do another test print soon and, if I don't see a difference, I'll forge ahead into a second liter of replenisher, despite the changing color and cloudiness in the developer.

    I've not tried keeping E-72 (made with either metol or phenidone) for longer than a month or two. My suspicion is that it wouldn't last extraordinarily long. OTOH, E-72 is a simpler formula than DS-14, so it's likely to be less intimidating to somebody who's just starting out with the mix-it-yourself approach.
     
  16. Gerald Koch

    Gerald Koch Member

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    The main problem with E-72 may be in its name. It is not equivalent to D-72 and does not produce the same image tone.

    Unlike DS-14 or DS-15 it does not contain anything to prevent the sudden death syndrome that ascorbate developers can exhibit.
     
  17. Ryuji

    Ryuji Member

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    My local photog friend left an open tray of DS-14 (actually it was a modified DS-14 but two generations before Tektol) for more than a full day and he compared prints from the same enlarger setting. No difference in image quality.

    I keep DS-14 in my Nova for many months and top up. Sometimes the inner surface of Nova gets dirty but I just use a buret washing brush to clean. (The stuff falls at the bottom of the slot until I start over the tank.) My Nova has loose lid that's not airtight, but the stuff goes for months. (By then the solution looks orange brown.) It makes sense that the same can be done with a tray and a bottle.

    I can't comment on DS-14 vs E-72 vis-a-vis, but I had several revisions of the print developer before DS-14, and I know DS-14 keeps much better than earlier ones that didn't use salicylic acid and TEA.