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  1. #131

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    Quote Originally Posted by albada View Post
    First, thank you for contributing to this thread. I seem to remember that you are the creator of the excellent Caffenol blog. Is that true?

    I chose propylene glycol because it's much less toxic than ethylene glycol. Also, the engine coolants available in America (are you in Europe?) have many additives in them, and I don't know what they'll do in a developer. So I was forced to order the glycol online, and PG is easy to buy online.

    I'm keeping a list of chemicals that can dissolve in PG:

    Phenidone to >= 2% (g/ml)
    Ascorbic acid to >= 20% (g/ml)
    Hydroquinone to >= 20% (g/ml)
    Borax deca/pentahydrate 21.53% weight/weight (25C)
    Boric acid (in insecticides)
    Sodium metaborate
    Citric acid
    Benzotriazole
    Do you know of more developer-chemicals that are glycol-soluble?

    Mark Overton
    No, I am not the creator of the Caffenol blog.
    I am just a computer and electronics engineer with great interest in photo and photographic processses.
    I have worked at a large photo finishing lab for some time, but that is some years back in time.
    Since I am used to set up and run test of different kinds, I am a practical kind of guy. I read about things and if it sparks my interest, I set up and run a test.
    If it works, well, great. If it doesn't work, well, that is valuable information too.

    The additives in engine coolants doesn't play havoc with developing agents as far as my experiments shows. They even may help us protect the developing agents from oxidation since they are introduced to prevent oxidation of engine components. One downside is that they contain lubricants to protect the waterpump bearings from wear. How much of a problem that is can be discussed. In working dilutions of 1:50 it doesn't seem to be a problem. The developer wets the film evenly without any problem.

    BTW. Engine coolants DO contain borax. Maybe the amount of added borax can be reduced since some borax is already in the liquid?

    Propylene glycol is difficult to find here in europe, at least here in Norway. Cheap engine coolant is availabe at every gas station. They may differ somewhat in what and how much anti-corrosion additives they contain, but borax is by far the additive in highest concentration.

    Sodium hydroxide pearls can be dissolved in small quantities in ethylene glycol. I suppose it may be dissolved in about equal small quantities in PG.
    4-5g in 100ml engine coolant is ok. If more can dissolved I don't know, but it isn't important, since 4g is already too much.

    I just read that popylene glycol wil degrade rapidly in air.

    From: http://www.ams.usda.gov/AMSv1.0/getf...TELPRDC5067083

    Degradation: In air, half will break down within 24-50 hours. In water and soil, it will break down within several days to a week.

    If this is correct, propylene glycol is not the container to use.
    Can anyone comment on this?

    Trond Solem.
    Last edited by Tronds; 12-22-2011 at 03:44 PM. Click to view previous post history.

  2. #132
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    From: http://www.ams.usda.gov/AMSv1.0/getf...TELPRDC5067083

    Degradation: In air, half will break down within 24-50 hours. In water and soil, it will break down within several days to a week.

    The above quote is inaccurate and misleading in this context. PG is very stable up to quite high temperatures. I think that they are referring to degradation in the open environment. In that case, a human body will go bad in about the same time perion!

    Both PG and EG are stable but EG is very much more toxic. Otherwise, their properties are quite similar for our purposes here.

    Both taste sweet and attract children and animals due to the sweet flavor. EG kills the subject, but PG can be used as a food additive.

    As for heating either with water, you run the risk of water boiling out. IDK what temperature is bad here due to the nature of both alcohols and their interaction with water.

    PE

  3. #133

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    Conclusion is EG can be substituted for PG as long as you have no plans drinking it!
    Both works and under normal circumstances (not trying to put any esoteric chemicals into the mix) no excessive heating nor boiling takes place; EG is perfect because it can be found anywhere there is a gas station.

    I use EG, in the meaning of engine anti-freeze concentrate (no water added), but prefer a simpler mix than Trond, but for me ts a fine container of AA and Phenidone (PC-Glycol) that last more than long enogh for me.

  4. #134
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    Umm, that is if the EG in antifreeze is free of ingredients that harm film or imaging. No one has come forth and proven that one yet!

    PE

  5. #135

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    Quote Originally Posted by Photo Engineer View Post
    Umm, that is if the EG in antifreeze is free of ingredients that harm film or imaging. No one has come forth and proven that one yet!

    PE
    The number of films I hva developed in PC-glycol with EG proves that.

    Absolutely no negative results except the negative itself, which in fact is positive, or well, it is a negative. :-)

    Remember that it is formulated to not attack rubber hoses, aluminium or other metal parts in the engine at high temperatures.


    I have tried just one brand of engine coolant, but if you try the cheapest one with the least advertized snake-oil additives you should be safe.
    I havent tried the red long-life versions since the blue one is more than good enough for the task.

  6. #136

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    Very simple PE or anyone else, just look up the recipe for PC glycol, go to the auto parts store or where appropiate and find one bottle of concentrated anti-freeze, blue type. Mix and test for yourself, it will be a peach.

    This is for PRACTICAL people, not theorizing.........
    If one haven't tried for oneself, there is no business telling anyone this will not work - on the other hand if one tries it, and reports back it did not work, it is very interesting to be part of the team figuring out why it did not work and what was done wrong - because it works without any trouble at all, when done properly.

  7. #137

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    The concentrated ethylene glycol antifreeze I found locally in 2 versions:
    For cars made after 1998-silicate free organic acid technology.
    For cars made before 1998-not stated.
    I wonder if there would be a preference for one of these two types.

  8. #138

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    Quote Originally Posted by Alan Johnson View Post
    The concentrated ethylene glycol antifreeze I found locally in 2 versions:
    For cars made after 1998-silicate free organic acid technology.
    For cars made before 1998-not stated.
    I wonder if there would be a preference for one of these two types.
    The first version is probably the long-life version that I never tried.
    Go for the version for cars made before 1998.

    If you can test pH of the silicate-free organic acid technology version and parhaps mix a small batch to see if it works, it would be great.
    Don't use it on a film with important pictures though.
    It may be even better, but it may also be a total disaster.

    You can read about antifreeze here: http://en.wikipedia.org/wiki/Antifreeze

    Note the part about propylene glycol.

    A little bit of poison in the solutuion may be beneficial since it inhibits bacterial growth.

  9. #139

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    Quote Originally Posted by analog what is that? View Post
    Conclusion is EG can be substituted for PG as long as you have no plans drinking it!
    I would worry that the manufacturer might change the formula of the antifreeze. For example, Trond mentioned that it contains borax. If the manufacturer changes the amount of borax next year, the pH will change, and the developer's activity will change. That's why I want to use pure chemicals: I'm guaranteed to get the same results every year.

    Having said that, I agree about using EG: I would be happy to use pure EG. I can safely change antifreeze in the car, so mixing EG in a developer is no problem.

    Mark Overton

  10. #140
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    As for practicality, my formulas have been on sale commercially since about 1970 and in modified form the first one is still being sold by Kodak. So, I have a lot of practical experience. I was also present during the development of some of the formulas mentioned here and knew the players in this area.

    Now, here is something for you to think about!

    I have used a particular home brew process and the results looked good, but I run keeping tests. After 5 years, some processed examples are showing varying degrees of brown or orange stain. These samples all looked identical at the start. I did run some analytical tests 5 years ago and found some differences between the samples. This is not related to the present case, but does show how things can go bad with keeping.

    The blue color is a dye. Who cares what color the inside of your car radiator or coolant tubing is? We do care about the color of our film! So, what if the blue colorant or film vehicle changes due to manufacturing changes by the companies involved? The film may end up blue! And, the blue color may change with time and pH as the CO2 in the air changes the pH of the film.

    Here are two theories based on practical results that I have observed in the lab at one time or another.

    So, as I said above, no one has proven that anti freeze is a fool proof solvent, and no one can prove that it will remain so into the future. If you are doing this, it is worth doing well, but then after all, these are only your photographs..

    Have fun with these ideas.

    PE



 

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