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.
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.
Originally Posted by john_s
So although this isn't claiming a case for dropping precautions, with good darkroom practice there should be no problems with selenium.
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.
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!
Originally Posted by tim rudman
So sorry for the error.
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.
Originally Posted by Tom Hoskinson
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.
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Amen to that Dave! With sensible handling and disposal, nothing presents a major hazard.
Originally Posted by Dave Miller
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.
"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.
Indeed. If you eat enough fresh green spinach, it will kill you.
Originally Posted by Jordan
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.
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.
Originally Posted by bonk
My photos are always without all that distracting color ...
"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.