Clean and Clear PaRodinal

Discussion in 'B&W: Film, Paper, Chemistry' started by ZorkiKat, Oct 4, 2006.

  1. ZorkiKat

    ZorkiKat Member

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    Finally, I was able to brew some paRodinal which is free from undissolved matter. Instead of using paracetamol tablets, I used pure, powdered paracetamol which is available from a local chemical house in quantities as little as 250 grammes.

    It wasn't the use of pure paracetamol alone which accounted for the clear brew. It was also probably due from the revamped mixing method. Using the procedure given for making paRodinal from paracetamol tablets (dissolve paracetamol, sulphite, then lye) resulted in a botched solution. A salt-like insoluble precipitate formed at the bottom of, and a foam-like froth floated on the mixing solution.

    The sulphite was dissolved first in a volume of water half the amount needed for the total volume of developer. Sulphite has to be dissolved in room-temp water. Then this is set aside.

    Then lye is dissolved in a similar amount of water. While the solution is still hot, paracetamol powder is added, which dissolves almost immediately. The lye+paracetamol solution is very clear at the start and shortly starts becoming slightly pink. The solution is then cooled by immersing its container in a pan of cold water.

    When the lye+paracetamol solution has cooled to room temperature, the sulphite solution is added to it. The resulting solution is neither murky nor dark. It's just like Rodinal as it comes out of a freshly unsealed bottle. My new batch of paRodinal is five days old and has not darkened yet. Initial
    tests with clipped film show that it develops just like paRodinal derived from
    paracetamol tablets.

    Here is a picture of the "clear" paRodinal in its bottle:

    [​IMG]
     
  2. desertrat

    desertrat Member

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    It's great to see that there is more work being done on this unique and useful developer. Just out of curiosity, do you teach at the University of Santo Tomas?

    I've figured out how to separate the paracetamol from the inert fillers in the commercial tablets, which are available very cheaply in the states. While searching for a suitable solvent, I stumbled across a very nefarious website dedicated to the synthesis of controlled substances for recreational consumption. :surprised: But I discovered that paracetamol is very soluble in alcohol, either ethanol or methanol.

    The procedure I used was to crush the tablets and put the powder in a jar. Enough alcohol was added so the powder at the bottom was about one fourth the final volume of solution. After resting overnight, the clear alcohol with paracetamol in solution was decanted off the top into a wide shallow bowl, leaving the insoluble fillers behind in the jar. The bowl was taken outside to the garage with the door open, and a hairdryer was propped up on a bench so it blew across the top of the bowl at a shallow angle. After a couple of hours running the hair dryer at the low setting, with the garage door open for ventilation, all the alcohol was evaporated and crystals of paracetamol remained in the bowl. Then the paracetamol was used to make a batch of developer, which is still in storage.

    The downside to this method is that the evaporation must not be done in a house, apartment, or densely populated residential neighborhood. Living on the outskirts of town, I was able to do this out in my garage, near the front, with the door open, and nothing else electrical running except the hair dryer.

    Disclaimer: I must state emphatically that I cannot recommend for anyone to repeat this experiment. Evaporating alcohol in a house can cause fire, explosion, or asphyxiation from the alcohol fumes mixing with air. Also, methanol and its fumes are intensely poisonous. I did this once to satisfy my curiosity. :rolleyes:

    Obviously, it would be much preferable to obtain paracetamol crystals when available, depending on where a person lives.
     
  3. marcsv

    marcsv Member

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    paracetamol capsules

    I get mine from paracetamol capsules, I'm currently using returned units by drugstores. I recently struck a deal with a pharma company, they agreed to supply me with the paracetamol I need for the brew, the catch is they are all in capsules, but I'm not complaining. I also got the same results. I'm not sure how long it would stay that way. The second version i mixed stayed pink up to the time I added KBr (roughly a month after mixing), the next day it turned brown. I gave Tom Hafalla a batch to test last week and sending out a couple more in a few weeks .
     
  4. derevaun

    derevaun Member

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    Brilliant! I wonder if you could just use the alcohol-paracetamol solution and count on it evaporating soon enough. Would it react with the hydroxide or sulphite? Would a little unevaporated alcohol affect the development process?
     
  5. eli griggs

    eli griggs Member

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    "But I discovered that paracetamol is very soluble in alcohol, either ethanol or methanol."

    "Disclaimer: I must state emphatically that I cannot recommend for anyone to repeat this experiment. Evaporating alcohol in a house can cause fire, explosion, or asphyxiation from the alcohol fumes mixing with air. Also, methanol and its fumes are intensely poisonous. I did this once to satisfy my curiosity."

    What about using grain alcohol, such as Everclear, rather than methanol?

    Also, what effect on the final product, if any, would this method bring about?

    Cheers,
    Eli
     
  6. gainer

    gainer Subscriber

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    For those who can get p-aminophenol base from Photographer's Formulary, are you saving money by using paracetamol? I can see using it if it's what you can get, but I'll bet the same chemical supplier who gets you the pure powder can get the paraminophenol base as well.
    Color of Rodinal or its clones, IMO, is not a good clue as to its condition. It takes only a little of oxidized Rodinal to make a strong color, and there's lots of the good stuff remaining in the stock. Even if you leave excess paraminophenol in the bottom to replenish the oxidized stuff, the color remains. It's the opposite of Xtol, which can die with little or no change of color.
     
  7. ZorkiKat

    ZorkiKat Member

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    Desertrat:

    Yes, I do. Any connection with UST?

    Doesn't paRodinal also fall under the category of substances used for recreational consumption?:D
     
  8. ZorkiKat

    ZorkiKat Member

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    marcsv

    Why not split the capsules and use the contents? That should be like the paracetamol I got from Alysons. What I got wasn't crystalline in form. It was
    fine powder, just like talcum. Perhaps its being in powder form accounted for its difficulty in dissolving in water. The crystalline form may dissolve more easily(?)
     
  9. ZorkiKat

    ZorkiKat Member

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    The local supplier only stocks "common" industrial chemicals. Paraminophenol isn't in their stock. They'd probably import it if I order a drum full :smile:

    My 3 year old Rodinal (half-full in its 125ml plastic bottle) has a lovely rich rust colour and it still works. My 9 month old paRodinal (also half-full in a plastic bottle) is muddy brown and slick from what remained of the tablet binders which went in with the rest when the developer was made. It also still develops film quite well.
     
  10. marcsv

    marcsv Member

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    splitting capsules

    That is what I do. I find i t theraputic...in some strange way. Yeah, it's hard dissolving the powder I'll try what you detailed in the previous post.
     
  11. desertrat

    desertrat Member

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    Hello Jay,

    I didn't know UST existed until recently. I did some googling to see if there were some other sites where your photography was posted, because I particularly like what you've been able to do with older Russian cameras, which are not generally held in very high esteem over here. I enjoy using them. I used to visit the Russiancamera forum at Beststuff.com, and I vaguely remembered a post you made that referenced teaching. I'm just a hobbyist, but there are educators here at APUG, and if they knew you were an educator also, I think they would like to know that. Would you tell us what you teach at UST?

    "What about using grain alcohol, such as Everclear, rather than methanol?
    Also, what effect on the final product, if any, would this method bring about?

    Cheers,
    Eli"

    Hello Eli,

    Everclear isn't avaliable in California. We can buy denatured alcohol, which is mostly ethanol with a little methanol and a few assorted ketones thrown in for good measure. This would probably work fine. I used methanol because I can get it dirt cheap in the form of Heet brand fuel additive for automobiles. It is nearly anhydrous methanol with one percent additives to prevent corrosion in fuel lines. Since I did the evaporation outdoors, and there are no homes nearby in the downwind direction, the fumes would be quickly diluted to a point well below the OSHA guidelines for workplace exposure. I don't have any way to determine how the alcohol and its additives effect the finished product of parodinal, but it seems to work OK. The paracetamol was still slightly damp with methanol when I made the developer, but it seemed to work about the same as a previous batch that had all the clumps and floating chunks in it.

    Since marcsv discovered that paracetamol capsules have little if any filler, the alcohol extraction is pretty much unnecessary unless a person lives where the capsules aren't available. If I had known this when I did the extraction, I might have still done it anyway just to satisfy my mad scientist cravings. But in the future I will probably use the contents of the capsules, after I run out of the tablets.
     
  12. ZorkiKat

    ZorkiKat Member

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    Hi desertrat

    I handle some photography (what else? :D)classes in UST. Just basic courses.

    Yep, I also used to visit Russiancamera at beststuff, but haven't been there because of some email glitches. The situation is probably true in many places- FSU cameras are looked down for being unreliable, or even unable to
    work at all. May be true in some cases, but a well-calibrated FED or Zorki is able to do what their Leica equivalents can do. Been able to "convert" a few to the creed too. Spreading paRodinal gospel is next :D

    Jay
     
  13. desertrat

    desertrat Member

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    Crystals?

    Hi Jay,

    Does your latest batch of parodinal have crystals at the bottom of the bottle? I looked hard at the image you posted, and thought I saw something along the bottom rim of the bottle, but couldn't be sure. Some have said that there must be a few crystals of PAP present, or the solution will deteriorate rapidly. What has been your experience with this?
     
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  15. ZorkiKat

    ZorkiKat Member

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    There is something settling at the bottom. It's something that's so fine but does not make the solution murky if ever they get stirred up. And they sink quickly too. I don't know if this is excess PAP. The dark areas seen on the bottom rim of the bottle isn't part of the solution at all, rather it's there as an effect of the way the bottle was photographed. There's a similar effect on the upper right portion of the bottle as well.

    Jay
     
  16. Xmas

    Xmas Member

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    Jay
    My opened '79 year 500ml plastic bottle is like tea and I'm going to need a new bottle soon even at 1:100, (when I get down to the solid dregs). I'd not worry about using immature 3 year opened bottles.
    What do you use for paper developing?
    Noel
     
  17. titrisol

    titrisol Member

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    Why evaporate???
    if you have filtered the starches and fillers form the acetaminophen you might as well just add water to your methanol/acetaminophen mixture.


     
  18. desertrat

    desertrat Member

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    The alcohol extraction was an interesting diversion, and it was kinda fun. But if you can get paracetamol without fillers, there's no need to use alcohol at all. And I guess there's no need to be too concerned about whether or not there are crystals in the bottom of the paracetamol bottle. If it doesn't start looking like strong coffee, and develops film, that's all that really matters!
     
  19. titrisol

    titrisol Member

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    IIRC, Rodinal/PaRodinal have to be supersaturated solutions of p-aminophenol
    It is therefore vey important to have those cristal at the bottom

     
  20. Fanshaw

    Fanshaw Member

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    When I made mine from tablets, I filtered it through coffee filter paper. Crystals formed at the bottom of the bottle afterwards.
     
  21. Gerald Koch

    Gerald Koch Member

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    This is not true!

    What is present in there solutions is either sodium or potassium paraminophenolate.

    Paraminophenol is amphoteric which means that it can react with either acids or strong bases. It reacts with hydroxides to form a paraminophenolate which is very soluble in water and explains its use to make highly concentrated developers. However, if there is an excess of sodium or potassium hydroxide used to make the phenolate then the resulting solution will oxidize rapidly. The presence of small amount of unreacted paraminophenol base insures that there is not an excess of hydroxide present. It's presence is only useful during the making of the concentrate as an an indicator. Afterward it's presence serves no purpose. There is nothing mystical going on here, just acid base chemistry.
     
  22. titrisol

    titrisol Member

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    Thanks Gerald, I stand corrected.
    I thought that having some p-aminophenol base helped with keeping the activity even though it looks like pepsi
     
  23. karavelov

    karavelov Member

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    Could we make a step further and react it with chloroacetic acid in order to obtain photo-glycin (N-(p-hydroxyphenil) aminoacetic acid) ?

    Just curious
    luben
     
  24. marcsv

    marcsv Member

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    I read somewhere that we can convert the excess of NaOH to Borax by the addition of Boric acid. What is the implication of the presence of borax in this brew?
     
  25. Blighty

    Blighty Subscriber

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    Dear all,
    Really intrigued by this formula, so I made some up today following Donald Quall's post: 6 Paracetmol tabs 500mg, 4g Sodium hydroxide and 10g sodium sulphite in 50ml of water. I haven't tried it yet, but at the moment it doesn't look to have changed colour and indeed looks very cloudy, thick and colourless. Is this usual?
     
  26. titrisol

    titrisol Member

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    YOu actually have to wait 3 or 4 days before it is ready to be used.
    The change from acetaminphen to p-aminophenol is quite slow at room temperature I believe