PCTEA anyone?

Discussion in 'B&W: Film, Paper, Chemistry' started by AshenLight, Mar 13, 2009.

  1. AshenLight

    AshenLight Member

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    Hi,

    I'm about to make my first batch of PCTEA. Mr. Gainer's formula suggests a mixing temperature of 250F according to The Darkroom Cookbook. He suggests a dutch oven but has anyone here mixed this with a lab hotplate/stirrer without blasting the darkroom portion of the house into the outer limits?

    Thanks,

    Ash
     
  2. ntenny

    ntenny Member

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    I've done it with a hot (just below boiling) water bath, stirring by hand. It worked OK, but I rushed too much in adding the ascorbic acid and got some solid glops of it in the bottom of the final product. If I'd been a bit more patient I think there would have been no problem at all.

    I'd premixed a stock solution of phenidone in propylene glycol, though, so I didn't have to worry about dissolving that. (I did that one the same way, with a hot-water bath, and let it sit for a few days in a warm room for the last of the phenidone to dissolve. No problems.)

    -NT
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    I believ Patrick revised his temperature recommendations when it was pointed out to him that there is a fire hazard when heating some of the organics to those temperatures.

    I'll let him speak for himself on the revision, but I myself would not use a stove, microwave or that high of a temperature.

    PE
     
  4. AshenLight

    AshenLight Member

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    I guess what has me wondering is that the warning on the bottle from Photographer's Formulary states that TEA is to be kept away from heat, sparks, open flame, etc. The MSDS for TEA states the flash point is 185C which is well below the 250F stated in the formula, but I don't want to take any chances. I'm very allergic to vigorous explosions in the immediate vicinity of my face and/or body.

    Ash
     
  5. Photo Engineer

    Photo Engineer Subscriber

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    Ash;

    There are numerous threads on flash point here and on PN. I suggest you look them over.

    PE
     
  6. AshenLight

    AshenLight Member

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    WIll do PE. Thanks...

    Ash (still in one piece)
     
  7. Jordan

    Jordan Member

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    I have mixed PC-TEA on a stirrer-hotplate with no ill effects, but I did it in a fume-hood. My advice to you is to work in a well-ventilated area and heat gently with good magnetic stirring until the components dissolve. You shouldn't need to go to 250F.

    250 degrees Fahrenheit is about 120 degrees C.
     
  8. AshenLight

    AshenLight Member

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    Whoops, meant to say the stated flash point of 185C is well above 250F. 185C = 365F
     
  9. Keith Tapscott.

    Keith Tapscott. Member

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    How would you make up the PC-TEA formula? Just curious.
    It seems to be a popular developer. http://www.flickr.com/search/?q=PC-TEA+
     
  10. Photo Engineer

    Photo Engineer Subscriber

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    Keith;

    I don't use PCTEA. I have my own formulas. In addition to which I don't believe in magic bullets for solving problems. Good old D-76 and HC-110 work well for me, or one of my own specialty formuolas if I want something special - but not magic.

    PE
     
  11. gainer

    gainer Subscriber

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    I never claimed anything magic, just a sulfite free developer concentrate that lasts a long time in storage.

    My revised advice about mixing included a covering of microwave-proof plastic wrap with edges sealed but loose enough so that the first signs of vapor pressure higher than atmospheric could be observed. That temperature is more than enough, and gives time to remove the source of heat before any contact between the atmosphere and combustible vapor can occur.

    Heating over an open flame or electric heating element is best done with low heat and a candy thermometer in the liquid. 150-200 F is hot enough. In fact, the precautions that are prescribed for making sugar syrup or taffy should be safe enough.
     
  12. dynachrome

    dynachrome Member

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    PC TEA

    When I last mixed up PC TEA I used the water bath method. I poured the TEA into a stainless steel cup and then placed the cup into an aluminum pan. I then poured boiling water into the pan and waited a few minutes to start stirring the TEA. The acsorbic acid should be added first to prevent oxidation of the phenidone. After the ascorbic acid is dissolved I add the phenidone. At the temperature I was working, the phenidone did not fully dissolve. I poured the mixture into a bottle and the rest of the phenidone dissolved on standing.
     
  13. AshenLight

    AshenLight Member

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    Thanks for all the advice everyone. Holding the TEA at 175F while adding first the ascorbic acid then the phenidone with constant stirring on a magnetic stirrer seems to have done the trick as far as mixing the developer goes. I'll be trying it out on HP5+ over the weekend.

    Ash
     
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  15. aparat

    aparat Member

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    I wonder your reasons are for trying a developer that requires so much effort (and hazard) to even have it mixed properly. There are so many developers out there that come pre-packaged. Why PC TEA?
     
  16. AshenLight

    AshenLight Member

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    The idea of a developer with D-76 like characteristics but a very long shelf life is appealing. Patrick's description of extremely fine grain with HP5+ (my favorite 400 speed film) was also interesting. It turned out that at the lower temperature, 175F, it wasn't so dangerous to try and the immediate availability in my darkroom of both ascorbic acid and phenidone made it worth trying. In fact, it seems less dangerous to make than a Rodinal type developer.

    Regards.

    Ash
     
  17. CBG

    CBG Member

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    Effort? Two components and a solvent. Stir and store. As simple to make as D-23 and arguably easier to use. The concentrated liquid stock means it can be measured out for use as a liquid. Very convenient to dose out with a child's medicine syringe.
     
  18. P C Headland

    P C Headland Subscriber

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    There's not much effort in making PC-TEA, and once you've made a batch up (I usually make 1 litre at a time), it keeps in concentrate form for ages. Plus it's cheap, and the ingredients are relatively easy to get hold of, and relatively safe.

    I make mine using Patrick's formula, but I mix the phenidone in a little methylated spirits (alcohol), and the vitamin C powder in a little warm water. Then I gently heat the TEA in a glass jug in the microwave until the jug feels about as hot as a hot cup of tea. Then I stir in the phenidone, when that has all been mixed in, I gradually stir in the vitamin C. I reheat it as necessary (to hot tea stage) and continue mixing until everything is mixed in. Then I bottle it into 250ml dark brown glass jars, let it cool down till it is warm, then cap it and cellar it!

    It is a nice developer that seems to give the better qualities of Rodinal along with the better qualities of Xtol.
     
  19. Keith Tapscott.

    Keith Tapscott. Member

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    Ron, I never considered PC-TEA as a magical-miracle brew, but more as a Phenidone + Ascorbate variant of the Kodak HC-110 type. I believe that HC-110 also contains ethanolamines. I also use D-76 as my standard developer.:smile:
     
  20. Photo Engineer

    Photo Engineer Subscriber

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    Keith;

    Good point in the underline. But my point, that you missed, was that if a formula exists, it exists to solve a problem. In this case it exists to reducing mixing hassle and keeping of concentrates. Does it do that in a safe, economical, reliable fashion and still give high quality results? IDK, the results are not in yet.

    I have seen reams of data showing the effects of D-76 and HC110 along with other film developers, along with picture data. I have seen a lot of things related to commercial products, but the entire story on PCTEA is not out there, just parts of it. So, there is no "magic", just feelings of comfort with it. Thats about it.

    I tend to believe that it is good for quality, but without proof, I cannot say for sure. I am concerned about people mixing it up in their kitchen in a microwave to the temperature of a "cup of tea". So, I am fence sitting until I see a reason for using it that is compelling.

    As I said, I can mix up similar formulas that take no heating.

    PE
     
  21. Jordan

    Jordan Member

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    A hot water bath is probably the safest way to heat triethanolamine in a non-lab environment.

    That said, working solutions of PC-TEA can just as easily be made by adding the constituent components directly to water in the right proportions -- 20 ml of triethanolamine, 1.8 g of ascorbic acid, and 0.05 g of phenidone in one litre of water (best to pre-dissolve the phenidone in a little alcohol). You lose the advantage of having a single-solution, very long-lasting developer, but no heating is required.
     
  22. P C Headland

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    You don't need to heat it (I didn't the first time I made some), but it makes it easier to ensure everything disolves.

    Can you explain what worries you have about warming TEA gently in a microwave (or water bath)?

    As for the fence sitting, maybe you could make make some up, then you can give us a run down on what you find. I'd certainly be interested in seeing your analysis. Remember, not everyone in this world has easy (or affordable) access to commercial developers, any many of the chemicals for other better known developers can be very hard to source.

    For me, PC-TEA is great since the ingredients are easy to get hold of, they are not especially harzardous, it is easy to mix, and it is long lasting. Last, but not least, it gives me great results.
     
  23. Photo Engineer

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    TEA is an organic base and as such is toxic to humans. If a microwave is used for chemicals and food, cross contamination is possible. TEA is also flammable and is subject to ignition on a stove or in a microwave if the flash point is exceeded. There are extensive posts on this subject here on APUG and on PN. I don't care to rehash them.

    As for making it without heating, see my previous post on this. I can make equivalent or better at room temperature and use more modern technology based on my EK experience. So, you are asking me to try a 50s Chevy that might catch fire when I have a brand new BMW that will not catch fire under any circumstances.

    Now, that is an an exageration of course, but I used it to emphasize that PCTEA is a rather simplistic formula with no hard data to back up image structure or curve shape. At least, none that I have seen here!

    The bottom line is that if it works for you, use it. For me, my negatives involve a lot of work. I prefer to use one of the industry standards to insure quality results.

    PE
     
  24. P C Headland

    P C Headland Subscriber

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    PE, thanks.

    I am well aware of the risks, but I don't think it useful if someone just says "it's dangerous", and doesn't qualify why. Adding the why to these threads helps to ensure that everyone is kept well informed - not everyone will search (or get their search right to return the right results) all previous threads.

    You're BMW analogy is not so great - even the new ones do, from time to time, go up in smoke!

    My images are important to me too, and I'm not going to gamble on something that might or might not work, or is inconsistent either. But, if I've tested something (to my own satisfaction), and others who I know come up with similar results, then I'm going to trust that it works.

    Maybe if we continue to use the car analogy, PC-TEA is an Ariel Atom - simple modern ingredients, with nothing extra added :wink:

    Given your extensive experience, would you be willing to do some tests with PC-TEA, so that there is some hard data?
     
  25. gainer

    gainer Subscriber

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    50's? In 1952 I graduated from WVU with a BS in Aeronautical Engineering, got married, went to work for NACA, and started learning how to DO engineering. Analysis of flight test data led to research in simulation and human factors, which led to design of a planetarium star projector that we could make in-house, which led to design of a compact device for observing a pilot's lookpoint on the instrument panel, which led to study of mathematical models of The Human Operator, so that by the time I retired, my position description read "Internationally known for non-linear mathematical modelling of the human operator." We had analog computers to do our simulations. Each user had a plug board for programming the computer. The other guys used to say "You can tell which board is Gainer's because it always has something hanging on it that doesn't belong there."

    Simplistic? Yes, indeed. The simplest way you can do a task is the best way.

    Toxic? How many of the chemicals we use in good old fashioned developers are not toxic? If you worry about TEA, mix the PC in propylene glycol and add whatever alkali suits your fancy at time of use. Throw in some sulfite if you think it will improve the results. You can also mix PQ-TEA or PQ-Glycol. See if I care, is how we ended other childish arguments.
     
  26. Photo Engineer

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    I'm not worried about TEA Patrick, I'm worried about HOT TEA in my microwave or on my stove! I use TEA all the time. I would like to mention that DEA is a big impurity in some samples of TEA and it is more volatile.

    I really don't care what anyone uses, as long as they are aware of any potential problems or dangers. Nothing more nor less. And, while you were chalking up all of those kudos in Aeronautical Engineering, I was getting similar ones in the field of photographic science and engineering and in chemistry. So?

    PE