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  1. #11

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    The article doesn't mention the many photographers who used pyro for years and did not get Parkinsons. To make such a broad generalization with regard to one individual (E Weston) is totally irresponsible.

    His claims are what is known as junk science. Junk science is speculation that has no basis in hard evidence or scientific research. Jorge presented hard data. If there is a research study somewhere that quantifies the death rate for photographers that use Pyro or similar compounds is higher than other photographers, that is hard science.
    "Fundamentally I think we need to rediscover a non-ironic world"
    Robert Adams

  2. #12

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    Garryl,

    I saw that report on the internet. I do not understand why the EPA and the FDA do not restrict its use. The only answer can be a conspiracy. A conspiracy so big that both John Kerry and G W Bush are covering it up.

    I have seen reports on the net that they both take very large contributions from the spigot of the DiHydorgen Monoxide corporate interests. It might even be part of the agenda of the Tri-Lateral Comission.

    The facts were pretty surprising to me. I mean I used to literally bath myself in the stuff in the darkroom. The most frightening thing is my oldest daughter dropped a tray containing some and was doused from head to toe. If I would have known then what I know now we would have gone straight to the emergency room.
    "Fundamentally I think we need to rediscover a non-ironic world"
    Robert Adams

  3. #13

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    I read Bond's article awhile back. It never should have made it into print. His methodology was poor. He failed to present scientific justification to back his technical arguments - heresay is not evidence. He did the community a disservice by publishing the piece.

    When you work with chemicals, wear personal protective equipment: gloves and safety glasses. Also get fresh air flowing through your workspace so you're not inhaling nasty fumes. Very simple steps can go a long way to mitigating risk. Weston (and many others) practically took baths in pyro and amidol. Not smart. We know they're bad enough that bathing in them is a very bad idea. But wear gloves and you've likely dropped your exposure level by a few thousand over not doing so. Hazardous chemicals only make you ill if you're exposed to them.

    I'd argue that the relevant figure-of-merit for expose is not LD50 but OSHA's specified 8 hour maximum permissible exposure level. EPA often offers a max exposure level of their own. The LD50 is the "lethal dose" at which 50% of those exposed die. The maximum permissible exposure level is usually much, much lower. That said, often times OSHA and EPA don't have enough data to make particularly scientific estimates of their max exposure numbers, so take them with a grain of salt.

    Wear gloves. Wear safety glasses. Put a fan in your darkroom. You do those things and you've probably got more to fear from meeting your end in a traffic accident than by being done in by Pyro.

    Chris

  4. #14
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    lol@dihydro mono oxide....or water! another product that contains pyrogollic acid that was not mentioned is topical medicinal ointments. Err on the side of caution and wear gloves. examination gloves are fine. If not your fingernails begin to turn brown from dyes. By the time you have processed your film the PMK has oxidized completely. Another thing. Gordon Hutchings who developed the formula, has been using the stuff without the gloves for a very long time well over 20 years. The harm from pyrogolic acid comes when it crosses the blood brain barrier. That happencs only when inhaled and quickly goes into the blood stream. Even at that it would take a large amount to do damage.

    I read the article. Funny how he didn't have an unsharp mask of the PMK negative to compare it to the unsharp mask of the Kodak one. As far as I remember you do tests that compare two items doing the same thing, except of one item of that process. In this case the change would only have been what developer and it's attendant processing that was used. All other variables should be exactly the same.

    BTW I want to thank the computer gods that with a new reformat of our main computer got rid of a gemlin preventing me from posting. Sean I don't know what it was, but it is gone now.

  5. #15

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    Quote Originally Posted by chrisg
    I'd argue that the relevant figure-of-merit for expose is not LD50 but OSHA's specified 8 hour maximum permissible exposure level. EPA often offers a max exposure level of their own. The LD50 is the "lethal dose" at which 50% of those exposed die. The maximum permissible exposure level is usually much, much lower. That said, often times OSHA and EPA don't have enough data to make particularly scientific estimates of their max exposure numbers, so take them with a grain of salt.


    Chris
    Not in this case Chris. While PELs are a safer guide for people who are in constant contact with toxic material, for the purpose of examining the maximum possible dose when exposed for short periods of times the LD50 is better, since we are looking for doses that are big enough to cause acute harm in a short period of time. This is an important distinction for those of us who develop infrequently but perhaps do it for longer than the 8 hour period used by OSHA.

    IOW, you can feed an animal 250 mg/kg of pyro for 1 month and kill it, or you can feed it 5 mg/kg for one year and kill it. You need to pick the appropriate dose for the appropriate length of time exposed.

  6. #16
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    I wonder if it is worse than some of the nasty chems in the E-6 process? Or C-41 for that matter? These are used regularly in both home and commercial labs.
    That is called grain. It is supposed to be there.
    =Neal W.=

  7. #17

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    Quote Originally Posted by Flotsam
    I wonder if it is worse than some of the nasty chems in the E-6 process? Or C-41 for that matter? These are used regularly in both home and commercial labs.
    Certainly not, color processes contain aldehydes to aid in the process and prevent mold and bacteria formation.

  8. #18

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    A useful document about the toxicity of pyrogallol is at:

    http://ntp-
    server.niehs.nih.gov/htdocs/Chem_Background/ExecSumm/Pyrogallol.html#humanexp

    I hope the line break does not break the url.

    Pyrogallol is clearly one of the things that you should protect yourself from, along with many other substances in the environment, our food, our workshops etc. A small amount of common sense is in order.

  9. #19

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    And I'd rather use PMK than make an unsharp mask for every negative. Call me lazy if you want.

    I've been a loyal reader (and buyer) of Photo Techniques for years, but I'm reviewing the situation.

  10. #20
    RAP
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    I have been printing for my 2006 calendar and was working on a negative, developed in HC110, because I needed a N+2 contrast. (N+2 in PMK is not recommemded) It is a mountain scene with white puffy clouds. Suffice it to say, the PMK negatives printed so much easier; better contrast control, tones, feel of substance. The HC110 negatives were much more diffucult to print. To try to get the feeling of puffy clouds was very diffucult with HC110. I will probably never develope cloudscapes in HC110 again. I used almost half the paper with PMK negatives and almost half the time.

    Right now, my favorite combo is TRI-X in PMK. I get far better results for extreme contrast reduction, N-3 in PMK, then I do with compensating development in HC110.

    BTW, I just tested the new TRI-X sheet film, with PMK, nothing has changed for me, same personal ASA and same development time.
    Time & tides wait for no one, especially photographers.

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