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  1. #21
    Donald Qualls's Avatar
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    Quote Originally Posted by George Papantoniou
    my claim was based on some things I read about the dangers of having your dental fillings (that contain Mercury) removed, a procedure which is causing some quantity of the amalgam to evaporate and (as stated by some alarmists on the web) create methyl mercury vapors.
    Unless you really like dentists, or have reason to believe the tiny quanities of mercury in your fillings is doing you serious harm, I wouldn't recommend getting your fillings removed. The process does *NOT* create methyl mercury, however -- all that's done is the old filling is drilled out and replaced by either a gold filling (expensive) or one made from dental epoxy (cheapish, relatively speaking, though I don't like epoxy fillings much and they don't hold up well on chewing surfaces). Either way, you're paying a dentist to perform a completely unnecessary procedure; the amount of mercury you absorb from a mouthful of amalgam fillings (after the initial curing period of several hours, that time when the dentist tells you not to eat anything and to rinse your mouth several times) is probably less than you'd get by being around locations where fluorescent tubes are carelessly disposed of.

    The fillings are effectively harmless where they are, and the process of having them removed isn't much worse (short term -- long term, it's a wash). I just don't see any reason to spend money on it, and your insurance company is likely to agree with me (which means you'll foot the bill out of pocket).

    Mercury *is* a poison, don't ever mistake that -- it's just not one that will chase you around the room, tackle you, and force itself into your system, unless already in an organic molecule (of which methyl mercury is the most virulent).
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

  2. #22
    Donald Qualls's Avatar
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    Quote Originally Posted by JG Motamedi
    That said, there was a case of serious mercury poisoning in recent years of a Daguerreotypist in Australia. He was improperly using the wrong kind of fume hood, and exhausted the mercury fumes directly back into his darkroom.
    I think a good case could be made that use of potassium cyanide as a fixer for wet plate/ambrotype/ferrotype is much more hazardous than use of mercury vapor to develop Daguerreotypes. However, if you're really, really concerned, there's always the Becquerel method, in which the exposed Dag plate is placed in a cabinet and exposed to dim red light for several days, then fixed when judged to be sufficiently developed. The plate is much slower when developed this way, and you don't see results for the best part of a week (compared to a half hour or so for mecury process), but there's no mercury in sight.

    Fuming the plates seems no great big deal to me -- bromine has such a strong smell that you couldn't breathe enough of it to do harm without noticing it, and it's also strongly colored, so a concentration high enough to do great harm with a single breath is actually quite visible. The same is true of iodine, plus the vapor pressure is so low that you have to heat the crystals to get enough vapor to treat the plate. The greatest potential for an accident, IMO, is in preparing the bromine fuming mixture, and working under a properly vented hood makes this little if any more hazardous than refilling the cells in a car battery without removing the battery from the car.
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

  3. #23
    JG Motamedi's Avatar
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    Donald,

    Great comments. Actually in current usage, Becquerel development can be done in about 2 hours using amberlith or rubylith with either a 500watt light or direct sunlight. Since Becquerel plates don't benefit from bromine fuming it is a simpler process, but about 2.5 stops slower. Also, Iodine doesn't have to be heated. The fumes created at room temperature are enough.

  4. #24

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    now this is one of the many reasons why i love this site
    (one big "knowledge-base")
    - john

  5. #25

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    Quote Originally Posted by JG Motamedi
    Donald,

    Great comments. Actually in current usage, Becquerel development can be done in about 2 hours using amberlith or rubylith with either a 500watt light or direct sunlight. Since Becquerel plates don't benefit from bromine fuming it is a simpler process, but about 2.5 stops slower. Also, Iodine doesn't have to be heated. The fumes created at room temperature are enough.
    Interesting thread as a friend and I are about to try making a Becquerel daguerreotype this summer - we are in the very early phase of trying to figure this out.

    You say that the speed is about 2.5 stops slower than a mercury fumed daguerreotype. What ISO would be a good place to start our exposure calculations?

    Thanks.

    Ehud

    PS: If anyone knows a place in Vancouver BC where I can buy some rubylith, please let me know.

  6. #26
    JG Motamedi's Avatar
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    What ISO would be a good place to start our exposure calculations?
    .005 ISO

    But don't forget they are orthochromatic, and a meter reading will only indicate how much light, not what color.

    Charlie Schreiner's site http://www.newdags.com/ has lots of information.

  7. #27
    MattKing's Avatar
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    Quote Originally Posted by eyaniv
    PS: If anyone knows a place in Vancouver BC where I can buy some rubylith, please let me know.
    Try here (kudos to Google):

    Stanley

  8. #28

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    Quote Originally Posted by MattKing
    Try here (kudos to Google):

    Stanley
    I called them this afternoon and they said that they do not carry Rubylith. Their claim was that all screen printers use emulsions now.

    Not a very helpful person on the phone.

    Thanks for the suggestion and yes, Google often deserves kudos.

    Ehud

  9. #29

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    Quote Originally Posted by JG Motamedi
    .005 ISO

    But don't forget they are orthochromatic, and a meter reading will only indicate how much light, not what color.

    Charlie Schreiner's site http://www.newdags.com/ has lots of information.
    Thanks. I have been to the site and quite enjoy looking at their pictures.

    An ISO of .005 will require some calculations but that is part of the fun, right?

    Ehud

  10. #30
    htmlguru4242's Avatar
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    This seems like such an interesting process to do, and seems like something interesting to try.

    Just out of curiosity, what is used nowadays as a silver plate to actually take the daguerrotype on? Obviously its a silver coated something, but is it still coated on copper? Do people make these plates themselves, or purchase them? If so, where?

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