Clean and Clear PaRodinal
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
Here is a picture of the "clear" paRodinal in its bottle:
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. :o 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.
Happiness is a load of bulk chemicals, a handful of recipes, a brick of film and a box of paper. - desertrat
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 .
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?
"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?
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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.
Originally Posted by desertrat
Yes, I do. Any connection with UST?
Doesn't paRodinal also fall under the category of substances used for recreational consumption?
Originally Posted by 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(?)
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
Originally Posted by gainer
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.
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.
Originally Posted by ZorkiKat