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Thread: Xtol Oxidation

  1. #11

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    The presence of an iron chelating agent in Xtol only slows oxidation by the Fenton reaction it does not completely stop it. Remember the reaction is dependent on the amount of iron (III) ions in the water. So those experiencing problems with tap water should use distilled or de-ionized water.
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  2. #12
    Rudeofus's Avatar
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    Quote Originally Posted by analoguey View Post
    I am seeing xtol turning deep blue. With usage. Working solution that is. Mixing it 1:3~
    Do you use a prewash? And if you use it 1:3, you use it single shot, yes?

    Quote Originally Posted by analoguey View Post
    Also, is anyone experiencing that thesolution is getting evaporated with use -that happens even if stored in cool conditions, in shade? (relatively cool -current temps 27-8c in night and 35+c in daytime)
    What do you store your Xtol in? Some containers will allow for more evaporation losses than others ...
    Trying to be the best of whatever I am, even if what I am is no good.

  3. #13
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    Quote Originally Posted by Gerald C Koch View Post
    The presence of an iron chelating agent in Xtol only slows oxidation by the Fenton reaction it does not completely stop it. Remember the reaction is dependent on the amount of iron (III) ions in the water. So those experiencing problems with tap water should use distilled or de-ionized water.
    Not experiencing problems with Xtol - negatives come out quite nice - I like they way they turn out actually. I don't know the process that you refer to - the Fenton reaction?

    With sheet film, I do pre-wash, not with 120. 120 I go direct to developer.
    Quote Originally Posted by Rudeofus View Post
    Do you use a prewash? And if you use it 1:3, you use it single shot, yes?
    Hmm, well I tried a bit of replenshing this time and it worked similarly as before, replenished with 100ml stock.

    Quote Originally Posted by Rudeofus View Post
    What do you store your Xtol in? Some containers will allow for more evaporation losses than others ...
    Thats the thing, it evaporated when I was using it - in the tray! The initial volume I poured into the tray was much higher than the final volume poured *back* into the bottle!! In-storage no evaporation.

    Developed at night, and only the xtol evaporated, not Dektol, not fixer. Not the water - well, okay I didnt measure that exactly.
    Last edited by analoguey; 04-16-2014 at 02:52 PM. Click to view previous post history.

  4. #14
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    Surely the sensible advice to ensure longevity of storage, regardless of what developer you are using, is to keep it in air tight containers prior to use.

    “The contemplation of things as they are, without error or confusion, without substitution or imposture, is in itself a nobler thing than a whole harvest of invention”

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    I don't know the process that you refer to - the Fenton reaction?
    The Fenton reaction is a particular type of oxidation catalysed by iron and copper ions. In the worst case it can destroyed the ascorbate in Xtol in a matter of hours.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

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  6. #16
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    Right, thanks Gerald!
    I dont see that happening here, but what I do see is the blue colouring - somewhat copper hue actually, like copper sulphate. Goes deeper with a bit of time and exposure to sun (in storage). But as of how, hasn't diminished in developing quality.
    I will shoot some more B&W and see how it goes, right now, most of 120 and sheet developing is done unless I shoot immediately - so might try some later on.

  7. #17
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    You do realize that you lose quite a bit of developer due to carry over, yes? Take a precise scale, weigh one of your film sheets, then soak it in alkaline solution, then weigh it again. That's the amount of developer you lose every time you develop a sheet.

    And about the blue color: look at the wash water if you prewash a roll of film. Without a prewash these dyes end up in your developer, are then changed by the Sulfite in your developer, but don't always go away completely. AFAIK these dyes do not interfere with development.
    Trying to be the best of whatever I am, even if what I am is no good.

  8. #18
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    Quote Originally Posted by Rudeofus View Post
    sun of sand, the difference in stability can be easily explained by the difference in tap water across the globe. People from Australia report, that their Xtol goes bad within days, while yours evidently lasts forever. The key issue seems to be Iron content of tap water. While Xtol uses a powerful sequestering agent (DTPA) to control the Fenton reaction, more Iron still means more remaining effect and less stability.
    Who are these Australians of which you speak? It's a big country. Is it those pesky South Australians with their "hard" water. Most Australians live in big cities with "normal" water supplies. I have always stored my XTol in "wine" bladders (usually 5 litre ex "pure" water bladders) and have never had a problem. Has been perfectly fine after 2 years in one case. I prefer my wine from bottles.
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  9. #19
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    Quote Originally Posted by Tony Egan View Post
    Who are these Australians of which you speak? It's a big country. Is it those pesky South Australians with their "hard" water. Most Australians live in big cities with "normal" water supplies. I have always stored my XTol in "wine" bladders (usually 5 litre ex "pure" water bladders) and have never had a problem. Has been perfectly fine after 2 years in one case. I prefer my wine from bottles.
    I have no idea whether Adelaide is a big town or a small hamlet, but Dr. Croubie and some Mr. polyglot both report that their tap water kills Xtol. Since their water won't pass the metal detector for air transport, and I am afraid of standing upside down for prolonged periods, I have no way to confirm or deny this.
    Trying to be the best of whatever I am, even if what I am is no good.

  10. #20
    Tony Egan's Avatar
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    Quote Originally Posted by Rudeofus View Post
    I have no idea whether Adelaide is a big town or a small hamlet, but Dr. Croubie and some Mr. polyglot both report that their tap water kills Xtol. Since their water won't pass the metal detector for air transport, and I am afraid of standing upside down for prolonged periods, I have no way to confirm or deny this.
    OK, that makes sense. Adelaide is special in so many ways, but not typical of the rest of Australia :-)
    http://www.tonyeganphotography.com/index.html
    "Those are my principles, and if you don't like them... well, I have others." Groucho Marx

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