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Thread: Chemistry 101

  1. #11
    richard ide's Avatar
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    I completely agree with you Gerald. Another important item which seems to rear it's head here is: Never ever put a chemical in a bottle which could be mistaken for a beverage. Besides not tasting good; there is a real possibility of serious harm.
    Richard

    Why are there no speaker jacks on a stereo camera?

  2. #12

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    Do not dispose used fixer down the drain. It will kill necessary bacteria at the sewage plant and will deposit toxic heavy metal ions in the environment. Recover the silver or dispose of at a hazardous waste facility.

  3. #13
    Photo Engineer's Avatar
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    And remember, that all of this is used against analog photographers by digital photographers. Ho hum.

    PE

  4. #14
    Roger Cole's Avatar
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    Quote Originally Posted by Monito View Post
    Do not dispose used fixer down the drain. It will kill necessary bacteria at the sewage plant and will deposit toxic heavy metal ions in the environment. Recover the silver or dispose of at a hazardous waste facility.
    Are you so sure of that in normal hobbyist quantities? It contains silver ion but the ions won't stay ions for long in nature much less a sewage plant. Metallic silver is microbicidal but in hobbyist quantities is it really any worse than washing with antibacterial soap and washing it down the drain?

  5. #15

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    I congratulate Gerald for starting this thread. He has said what has needed to be said on this and several other forums. I am not a chemist but I studied, enjoyed and absorbed the subject in high school and at introductory college level. I probably know just enough to understand how little I really do know but certainly enough for it to have been useful in a 40 year photography career (I am totally out of my depth when guys like PE who are chemists discuss things like organic synthesis).
    The lack of knowledge of chemistry displayed by people who propose mixing wierd and wonderful concoctions appalls me. People who don't seem to even understand the purpose of the components in a simple developer write seeking help as to the possible effect of adding some obscure chemical they have read about that is most likely unobtainable in any modest quantity.
    I saw last year on another forum a suggestion that it was cheaper to make silver nitrate from scrap silver and nitric acid than to buy the substance. The guy who made the suggestion was under the impression that this reaction produced silver nitrate and water - as it does but he was unaware of the deadly nitric oxide also produced. There is also a video on YouTube that demonstrates this reaction but some good samaritan who cautions about the dangers also gets it wrong by saying that the gas produced is nitrogen dioxide (also dangerous but at least it is brown so you can see it).
    As others have said, you can fully enjoy photography, including the darkroom, without knowing much about chemistry apart from general common sense safety precautions but if you want to start mixing chemicals together for any purpose you owe it to yourself and others to learn some chemistry. OzJohn

  6. #16
    Maris's Avatar
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    Quote Originally Posted by Roger Cole View Post
    Are you so sure of that in normal hobbyist quantities? It contains silver ion but the ions won't stay ions for long in nature much less a sewage plant. Metallic silver is microbicidal but in hobbyist quantities is it really any worse than washing with antibacterial soap and washing it down the drain?
    Roger Cole is right. In moderate quantities (pounds, not tons) silver tetrathionate and similar compounds which characterise used fixer don't harm sewerage treatment systems. The silver very quickly gets converted to silver sulphide in the presence of the free sulphide ion. Silver sulphide is geologically stable and inert and has one of the lowest solubility products known in chemistry. The stability and inertness of silver sulphide is the key to the remarkable archival properties of sepia toned photographs.

    Before my darkroom was approved by my local council I had to calculate the silver concentration in my total household effluent. I'm pretty busy and use a few thousand sheets of film and paper per year but the result came to about 5 parts per billion. By the time this mixes with the output of the other 20 000 households that don't process photographic materials the silver concentration is below any conceivable detection limit down at the sewerage treatment plant.
    Photography, the word itself, invented and defined by its author Sir John.F.W.Herschel, 14 March 1839 at the Royal Society, Somerset House, London. Quote "...Photography or the application of the Chemical rays of light to the purpose of pictorial representation,..". unquote.

  7. #17
    MattKing's Avatar
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    Quote Originally Posted by Monito View Post
    Do not dispose used fixer down the drain. It will kill necessary bacteria at the sewage plant and will deposit toxic heavy metal ions in the environment. Recover the silver or dispose of at a hazardous waste facility.
    It is a good idea to recover silver, but used fixer doesn't contain enough silver to cause damage unless you produce relatively huge quantities.

    If you are looking for a way to recover silver, check with jnanian here on APUG - he sells a unit that can do this for you.
    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

  8. #18

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    It may be true that we can get away with disposing silver down the sewers with little environmental impact, but I still think it is not responsible unless it is really necessary. There is so little mercury in batteries, for example, yet we are strongly encouraged to keep them out of landfills. I have only just recently begun fixing (and developing) again after many years not doing it, during which environmental awareness and understanding has increased.

    Perhaps the silver ions get bound up with sulfide but that material gets deposited somewhere. Environmental leaching is much harsher than what a gallery print experiences. Further, microbes and invertebrates eat it and digestion can free up the ions again in the food chain.

    An added reason to recover silver is the value of the metal. It is likely that the quantities we can recover can hardly repay us for our time as an economic activity, but if nothing else it appeals to my hobbyist side. I have researched a little about the electrical requirements and would like to design and make a simple solar powered recovery system, which would require only a small cell area I think (rough estimate less than a square foot).

    So, dump your silver if you insist, but I think we can do better. Doing better would either be the responsible thing to do or it would be good PR by appearing to be responsible.
    Last edited by Monito; 09-28-2011 at 06:03 AM. Click to view previous post history.

  9. #19
    Steve Smith's Avatar
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    Quote Originally Posted by Maris View Post
    Before my darkroom was approved by my local council
    You have a council approved darkroom?


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  10. #20
    ruilourosa's Avatar
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    a little explosion and some toxicity gives a adrenalin rush not possible with digital photography...
    vive la resistance!

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