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  1. #171
    Mike Bates's Avatar
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    Quote Originally Posted by albada View Post
    This is a good idea!

    I would give you one caution though: You'll notice from nearby postings by kb3lms, Dave Krueger and myself that XTOL tends to form a thin film of precipitate on the bottom after storage for a few weeks or a couple of months. Since your tap is on the bottom, any precipitate will come out first. So if it's been a few weeks since you dispensed some XTOL, I suggest examining the beaker for bits floating around.

    Mark Overton
    The tap is actually an inch or so above the bottom, so I'd have to tip the bucket to get the last of the Xtol. I dispense into a clear graduated cylinder and add water to make a 1:1 solution. I've never seen any precipitate in the solution. I mix the stock solution with heat distilled water to avoid any extra minerals that may precipitate out. I understand some people have seen some in spite of that.

    In reality, there might be a little precipitate in the bottom of the bag and I wouldn't notice it. Xtol is pretty cheap, so when it starts getting low, I mix a new batch and store it in a new bag waiting to be installed in the bucket. I rarely try to drain the old back completely dry because of the potential for dregs at the bottom.

    Keep up the good work. I'm a big fan of Xtol and your work may lead to a perfect (or better!) substitute if Kodak eventually stops making it.

    mike

  2. #172
    MattKing's Avatar
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    Here is a Canadian source for this dispenser - it may in fact be where it originates: http://www.winemakeri.com/Wine_dispenser_p/17132.htm

    With respect to the precipitate, it seems to me that if one is using X-Tol in a replenishment regime, small amounts of precipitate in the replenisher solution are unlikely to be a problem, so the dispenser should be perfect for it.
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  3. #173

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    Quote Originally Posted by Alan Johnson View Post
    Is it needed to multiply the weight of metaborate by 1.354 (see post 85) if 8-mol metaborate is supplied?
    Is there an approximate multiplier of Xtol time for development?
    Hello Alan,

    This developer is the same as your D316, except that the metaborate is 2.0 g/L instead of 2.2 g/L. The slightly lower pH means the times will need to be lengthened a bit from D316. For TMY2, the multiplier is 2.19, but that assumes it's formulated as a concentrate. The PG in a concentrate slows development a little, hence a slightly longer time.

    And yes, I assumed the use of metaborate 4-mol (dihydrate), so 8-mol will need more.

    BTW, if you want to use D316, you can add 40 g/L of sulfite instead of 45, and that will give similar results and the same times as above. I tested 40 g/L with D316, and the grain matches XTOL. This new brew has a hint finer grain, but I suspect most folks would not consider the improvement to be significant.

    Yesterday, I tested 50 g/L of sulfite and dropping the metaborate to 1.8 g/L to keep pH unchanged. My preliminary results give an XTOL time-ratio of 2.15, slightly finer grain, and slightly lower true speed (1/5 stop speed-loss). The appearance of the grain is also more attractive due to fewer worms, so this is a promising brew.

    Mark

  4. #174

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    Quote Originally Posted by foto_mike View Post
    Keep up the good work. I'm a big fan of Xtol and your work may lead to a perfect (or better!) substitute if Kodak eventually stops making it.
    mike
    Mike and Jason: Thanks for the encouragement. My original motive for creating a concentrate was to avoid waste because we occasional shooters can't use 5 litres in 6 months. But Kodak's bankruptcy has heated the fire under me. I love XTOL, and want to be certain a proven replacement is available in case Kodak's B&W division is dismantled.

    Mark Overton

  5. #175
    kb3lms's Avatar
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    ...want to be certain a proven replacement is available in case Kodak's B&W division is dismantled.
    Not only that, though. I've started reading photo journals and magazines from the late 1800's, ie pre-Kodak. In fact, one issue from 1884 gave details of one of Eastman's original patent submissions. Another article I read was about going out for a demonstration (we'd call it a review today) of the original Kodak box camera with 100 exposures inside that you sent back for processing. (The newspaper editor receiving the demo was rather dubious that the product would ever catch on!) Anyway, my point is that there was no Kodak and although there were small vendors of materials it was an enthusiast market and they all made their own stuff. There was an atmosphere of experimentation and sharing as they each found the next great thing. It was all incredibly "high-tech" stuff. But also, the amatuer enthusiasts could be, and were, just about as deep into it as the corporate giants (such as they were) of the time. And, you might be surprised at how little the technology has changed since that time, other than the major leaps like panchromatic dyes. It's amazing what those guys knew!

    In a post-Kodak world, should that come to pass - and maybe even if it doesn't, I believe we analog folks will come full circle and pick up much where these guys left off when Kodak, Agfa and Ilford seriously entered the picture and it became much more practical to buy economical well made materials than to try to understand and make them your self.

    The big difference for us being that we know what's possible because it has already been done. But unless the treasure trove knowledge vaults of Eastman Kodak are suddenly spilled open, we will have to follow the bread crumbs and re-discover it all. So. it's you filling in a developer here, me figuring out how to coat PET in another thread, Denise with an emulsion, PE sharing everything that he knows, Holmbergers up to something, and someone else creating a great new formula or method for something else that will pick up all these pieces and everyone can play a part. Maybe the world is opening up - not shutting down.

    So, your developer is great stuff! Can't wait to try it!

    (enough of the cathartic now)
    All this has happened before, and all this will happen again.

  6. #176
    kb3lms's Avatar
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    To continue with the technical discussion, Mark, you mention that development times are longer for this formula than XTOL. I see above where you say the time multiplier for TMY is 2.19. Do you have a general idea where we might start with development for a given film (say HP5 or Fomapan 100) based on XTOL? Do you think 2.2 might be a good number? I'm sure it will vary somewhat for each individual film. Just looking for general guidance.

    -- Jason
    All this has happened before, and all this will happen again.

  7. #177

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    Quote Originally Posted by kb3lms View Post
    To continue with the technical discussion, Mark, you mention that development times are longer for this formula than XTOL. I see above where you say the time multiplier for TMY is 2.19. Do you have a general idea where we might start with development for a given film (say HP5 or Fomapan 100) based on XTOL? Do you think 2.2 might be a good number? I'm sure it will vary somewhat for each individual film. Just looking for general guidance.
    -- Jason
    Jason, thanks for sharing the experimenters' approach and attitude. You got it right! I find that it is an adventure. It's almost like explorers of old looking for new lands: I enjoy discovering something new. Surprisingly, even after all these decades, there are still discoveries to be made in B&W developers. Anyway, the formula for this developer looks like something that was diluted 1+1, but it was actually designed that way, and is matching or even beating XTOL's image-quality.

    The 2.2 is as good a guess as any for different films. The pH is lower, which films probably respond differently to, so a little dialing-in will be needed for each film.

    I didn't know you were working on coating PET. Wow! Maybe I should pay attention to the other forums out there. A quick search showed the long substrates thread.

    Mark Overton

  8. #178
    polyglot's Avatar
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    Quote Originally Posted by albada View Post
    Mike and Jason: Thanks for the encouragement. My original motive for creating a concentrate was to avoid waste because we occasional shooters can't use 5 litres in 6 months. But Kodak's bankruptcy has heated the fire under me. I love XTOL, and want to be certain a proven replacement is available in case Kodak's B&W division is dismantled.

    Mark Overton
    I absolutely do not want to discourage you from this work, because access to a liquid-concentrate long-life XTOL would be fantastic even if it's just a recipe. But I should point out that Xtol-equivalent developers are available from Freestyle under generic brands, though I've not tried them. Personally, I just bought 15 bags of the yellow and I expect they'll last me a decade.

  9. #179
    Murray Kelly's Avatar
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    It is with increasing awe and wonderment at Mark's work on this project as I sit on the side, sandbagging. Thanks for all you have done, Mark.
    For the chemists here I ask if oxalic acid would work as an Iron getter? Perhaps it would ruin the developing agent too? I find it easy to get tho others may have difficulty.
    Murray

  10. #180

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    No oxalic acid is a poor chelator for iron (III).
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery



 

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