Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,912   Posts: 1,556,249   Online: 1062
      
Page 3 of 7 FirstFirst 1234567 LastLast
Results 21 to 30 of 62
  1. #21
    bonk's Avatar
    Join Date
    Mar 2007
    Shooter
    Med. Format Pan
    Posts
    129
    Images
    3
    I guess I will get some of those "nitrile gloves" you mentioned. Is there anything to watch out for or do I just google "nitrile gloves" and buy what I find? I mainly find those medical ones. Can I use them for everything else in the darkroom as well? Can I wash and reuse them?
    Last edited by bonk; 11-18-2007 at 04:00 AM. Click to view previous post history.

  2. #22
    Martin Reed's Avatar
    Join Date
    Sep 2004
    Location
    North London
    Shooter
    Multi Format
    Posts
    325
    Quote Originally Posted by john_s View Post
    If you've done a good rinse down I doubt that you're in the slightest danger. Many people take a selenium supplement for health reasons and you might have just got a one or two day dose of selenium.
    I tend to agree. A few years ago a colleague regularly used a technique he had worked up which included selenium toner heated on a dishwarmer, and his darkroom was non too well ventilated either. On one occasion he became convinced he had poisoned himself with selenium and took himself off to the relevant London hospital (forget which one, but it was that one dealing with poisoning issues like this). After going through this little used test it transpired that on a scale of 1-10 he wasn't even registering on the bottom rung.

    So although this isn't claiming a case for dropping precautions, with good darkroom practice there should be no problems with selenium.

  3. #23
    Dave Miller's Avatar
    Join Date
    Dec 2003
    Location
    Middle England
    Shooter
    Medium Format
    Posts
    3,894
    Images
    2
    My understanding is that with sensible handling none of the chemicals we use in our darkroom should present any hazard to health.

    As an aside I recall that the selenium required by our bodies, and that used in toning are two different forms. Can anyone confirm, or refute that? It seems relevant least someone take a swig of the Kodak product as a diet supplement.
    Regards Dave.

    An English Eye


  4. #24
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,187
    Images
    65
    Quote Originally Posted by tim rudman View Post
    I didn't write this book PE. Did you mean Gordon Hutchings?
    Tim
    Apologies to Tim, yes it was Gordon Hutchings. And IDK how I did that as his (Gordon's) book and A&T were sitting side by side next to me as I wrote that!

    So sorry for the error.

    PE

  5. #25
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,187
    Images
    65
    Quote Originally Posted by Tom Hoskinson View Post
    Sorry, Argument from authority, argumentum ad verecundiam is a logical fallacy, because the validity of a claim does not necessarily follow from the credibility of the source.

    Also, If one wants to avoid contact with hydroxybenzenes (like hydroquinone, catechcol and pyrogallol) avoid barbeque's, smoke from wood fires and especially avoid tobacco smoke. Also, avoid Coffee. Include Dektol and any other developers that contain hydroquinone in your avoidance list.
    This is quite true, however it is difficult to get volunteers to test the toxicity of tri hydroxy benzenes. Many sources do quote LD50 in rats and mice of all of these hydroxy compounds, and of them all, hydroquinone and metol are rather low causing kidney and liver damage but have a rather high LD50.

    The tri hydroxy compounds kick toxiciity up a notch as Emeril would say, at least according to several sources. As you say, quoting them does not make them valid, but why take a chance and be an unwilling 'volunteer'. Use rubber gloves and use a mask when mixing powders.

    BTW, the most toxic materials in charcoal fires and tobacco smoke by far are the benzopyrans as a class. They are major carcinogens and are also found on the surface of BBQd meats. In fact, you are getting more of the pyrans than you are of the HQ derivatives in smoke. HQ in smoke is almost an oxymoron as a reductant is not a major product of oxidation. You might want to check your sources on that.

    Quinones OTOH are found in smoke and also in colored autumn leaves. Anthroquinones are a product of ageing of leaves when frost damages them. Quinhydrone was used for years as the colorant in green ink. It is a green byproduct of the oxidation of HQ in the absence of sulfite.

    PE

  6. #26
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,187
    Images
    65
    Quote Originally Posted by Dave Miller View Post
    My understanding is that with sensible handling none of the chemicals we use in our darkroom should present any hazard to health.

    As an aside I recall that the selenium required by our bodies, and that used in toning are two different forms. Can anyone confirm, or refute that? It seems relevant least someone take a swig of the Kodak product as a diet supplement.
    Amen to that Dave! With sensible handling and disposal, nothing presents a major hazard.

    And, the selenium in toner is quite different in chemical form than that used in dietary supplements. IDK offhand the difference as I have not looked into it for years.

    BTW, one of the major portions of my research in graduate school involved the use of selenium oxidations. So, I have used it by the pound as selenium oxide. It smells like garlic to me.

    At Kodak, selenium is used in large quantity in chemical syntheses, but they take great precautions to prevent chemical spills and vapor leaks.

    Selenium is a major dopant in computer chips. If you have a short in any electronic equipment and smell that characteristic garlic or 'electronic' odor, that probably contains some seleniium compound or other. And, I am not referring to the smell of burning insulation. That is different.

    PE

  7. #27

    Join Date
    Sep 2004
    Location
    Toronto, Canada
    Shooter
    Multi Format
    Posts
    587
    "The dose makes the poison" -- a statement first made in the 1600s, I think, and that still holds today for most substances (some hormone-like organic small molecules violate the rule). Selenium is indeed considered a "micronutrient" -- many otherwise toxic elements are too -- but IMO you can't use that fact to diminish the potential health risks of working with these kinds of substances.

    In the case of selenium, the line between micronutrient benefit and risk for selenosis seems to be at 400 ug per day for adults (see http://dietary-supplements.info.nih....s/selenium.asp -- Table 4, about 2/3 of the way down the page) and about half that for children. That's less than half a mg of elemental Se, which I would estimate to be equivalent to maybe 2 mg of dried KRST.

    PE did SeO2 oxidations as a grad student and survived unscathed because he handled it properly and was careful to avoid inhaling or ingesting the dust (i.e. didn't eat in his work area).

    My $0.02 only.

  8. #28
    JBrunner's Avatar
    Join Date
    Dec 2005
    Shooter
    35mm
    Posts
    6,780
    Quote Originally Posted by Jordan View Post
    "The dose makes the poison" -- a statement first made in the 1600s, I think, and that still holds today for most substances (some hormone-like organic small molecules violate the rule). Selenium is indeed considered a "micronutrient" -- many otherwise toxic elements are too -- but IMO you can't use that fact to diminish the potential health risks of working with these kinds of substances.
    Indeed. If you eat enough fresh green spinach, it will kill you.

    FWIW- I always wear nitrile gloves in the darkroom, have good ventilation, and wear a mask when mixing powders. These measures are common sense. Some of the things in my darkroom are toxic, so I eliminate as much exposure as possible.

    Common sense in personal protection, safe handling, responsible storage, and proper disposal of chemicals goes a long way, very much farther IMHO than worrying about the individual toxicity of a given compound. That said, it behooves one to know what one is handling, as well.

    J

  9. #29
    fhovie's Avatar
    Join Date
    Mar 2003
    Location
    Port Hueneme, California - USA
    Shooter
    Large Format
    Posts
    1,247
    Images
    92
    Nitrile gloves - ebay? I think that is where I bought my last 3 boxes. They should be as easy to get as anything else on the the internet. They are not reusable. They are not as stretchy as latex but are a better barrier to smaller molecules. They also do not lead to a latex sensitivity that is common in people that wear a lot of latex gloves. you don't want to get that problem. Getting ones that fit right is more difficult than with latex - latex will fit to you, nitrile will not be as forgiving. If you get them too big, you will not have the tactile response you need and too small and they rip going on.

    This whole thread is like discussing reloading ammunition, if you are careful and sober, it is very safe. If you are careless, the angels sing. In my darkroom there are chemicals that can produce amazingly toxic gases. There are chemicals that I can taste if they get on my skin. But with respect and care, they are safe and easy to work with. Gloves and a face mask for powders. None of them are so toxic that a drop on my skin will kill me. It is preventing the repeated and prolonged exposures that makes it safe. A drop splattered in the sink is not an event - Rinse like you would a drop of food coloring and you are good to go. No fear! Just respect and care.

    Quote Originally Posted by bonk View Post
    I guess I will get some of those "nitrile gloves" you mentioned. Is there anything to watch out for or do I just google "nitrile gloves" and buy what I find? I mainly find those medical ones. Can I use them for everything else in the darkroom as well? Can I wash and reuse them?
    My photos are always without all that distracting color ...

  10. #30

    Join Date
    Nov 2005
    Location
    Los Angeles, CA
    Shooter
    Multi Format
    Posts
    5,137
    "Symptoms of selenosis include a garlic odour on the breath, gastrointestinal disorders, hair loss, sloughing of nails, fatigue, irritability and neurological damage."

    And all this time my wife thought it was just my natural personality. I'll have to let her know it is the toner that makes me like this.

Page 3 of 7 FirstFirst 1234567 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin