How poisonous is selenium? : LUSENET : B&W Photo - Printing & Finishing : One Thread

If I have a large print order to tone, I sometimes get lazy and lift prints out pf the selenium/HCA solution (1:20 dilution) with my bare fingers insted of the usual tongs or rubber gloves. Today I did that for about two hours. How poisonous is selenium, and Hypo Clearing agent for that matter? Any symptoms one should look for? Thanks

-- Ted Davis (, March 26, 2001


I haven't used print tongs for 15 years. I found in the past the once in a while my skin would have a very mild rash from selenium. I know that no responsible person or doctor will tell you that it is safe to have direct contact with selenium although you will find it in the multivitamin that you take every day. After is death, Ansel Adams had an autopsy performed to see if the life long exposure to photographic chemicals did any damage to his body. The finding was that no damage was found that could be attributed to chemical exposure. I would suggest that you continue to do what ever procedures that you feel are safe but I doubt that any long term damage has occured from this couple hours of exposure.

-- Jeff White (, March 27, 2001.

The short answer is: very...On the other hand,many old timers use nothing but their bare hands throughout the development and toning.I know one printer who's been dipping his hands in photographic chemicals on a daily basis for over 35 years (he also smokes like hell on top of that!), and he is still alive and kicking -quite famous actually.Go figure...The moral of the story is that i wouldn't worry about a session,or two (i've done it myself many times);but if you are toning prints on a continuous basis,it's probably a good advise to use rubber gloves (surgical gloves work great,for exemple;don't confuse them with inspection gloves which are pretty much useless for this purpose).I don't like tongs,especially for toning,they make damaging prints too easy.
Hypo clearing agent is not poisonous,as far as i know.

-- Cem Topdemir (, March 27, 2001.

Thanks guys, I feel a bit less nervous. You see, all afternoon post toning session I had a slight metallic taste in my mouth that the paranoid in me swore was the beginning sign of some sort of poisoning. I won't take any chances tomorrow though, will wear the surgical gloves.

-- Ted Davis (, March 27, 2001.

Well, although selenium is in fact an important trace element, and you can buy pills containing selenium (and other antioxidants) in health food stores, selenium is extremely toxic, and may lead to cancer in case of long-term low-level exposure. AFAIK, it is readily absorbed through the skin, so I would NEVER put my hands into selenium toner.

Hypo clearing agent is far less hazardous, but I would want to pour it over my breakfast cereals either. I always regarded it as good printing practice to handle prints either with tongs or with gloves, not only for my own health, but also to avoid contaminating the prints, thus jeopardizing their permanence. What is the point of washing prints to archival standards if you handle them with fingers that have been immersed in hypo-containing solutions (such as Se toner)?

As for the danger of damaging prints using tongs: There are a lot of good tongs around, and leaving an unexposed rebate around a print is a good idea anyway. So?

Regards, Thomas Wollstein (

-- Thomas Wollstein (, March 27, 2001.

I guess there are as many opinions as there are people. I think you are in more danger from inhaling the fumes than from absorption through your skin. Be sure to use selenium toner in a well-ventilated darkroom. I've had very bad luck with tongs, particularly with large prints. I generally pick up prints by two corners with my thumb and forefingers--I can't see that this small amount of exposure could be particularly hazardous. I carefully wash my hands in soap and water after any contact with fixer or selenium toner, so as not to contaminate other prints. I have tried using gloves, but find them inconvenient to take off and put back on--still, they're a better choice than print tongs.

-- Ed Buffaloe (, March 27, 2001.

Pure Selenium is extremely toxic, and the main symptom of low level poisoning by it is chronic halitosis (bad breath). Salts of Selenium should be treated with the same care and respect.
I had to Ion-beam mill some selenium composite material in a vacuum chamber a couple of years ago. Even after being pumped down to a fraction of a part per million, the vapour left a horrible lingering smell of rotten cabbage in the machine. I would hate my, or anyone else's, breath to smell that way.

-- Pete Andrews (, March 27, 2001.

If you don't like tongs, use latex gloves when handling prints in selenium.

NEVER let spilt selenium toner dry. Wipe it up, then wipe down with damp paper towels. Repeat. Repeat. Put the towels you used to wipe it up in a sealed plastic bag before you throw them out.

The dust is exceedingly hazardous to your lungs.

-- Charlie Strack (, March 27, 2001.


According to the MSDS on Kodak's Rapid Selenium Toner, exposure by skin contact for short periods is not very dangerous because of the high level of dilution. Short term exposure can cause problems with skin rashes and the like for some people. Long-term exposure by skin contact can result in liver damage. Two hours won't hurt you, two hours a day for 40 years can have dire consequences. Exposure by ingestion is the most dangerous route of exposure. That should be pretty obvious. If your breath and sweat smell like garlic, according to the MSDS, you are ingesting and/or absorbing excessive amounts. A metallic taste in the mouth is another sign, as well as rashes and skin lesions. Exposure to the concentrate will have proportionately greater effects, and exposure to sodium selenite in powder form can be highly toxic.

As for HCA, it consists mostly of sodium sulfite, which is about the most benign of all the chemicals we use in the darkroom. It is not significantly toxic by skin contact, but can cause problems with ingestion or inhalation. Sodium sulfite is also one of the components of Rapid Selenium Toner as is sodium thiosulfate. Both sodium sulfite and sodium thiosulfate will put out sulfur dioxide if they come into contact with acids.

-- Ken Burns (, March 27, 2001.


>> I think you are in more danger from inhaling the fumes than from absorption through your skin.

I think that's not true. I don't expect selenides in solution to be very volatile, just as sodium chloride (salt) does not evaporate from salt water. (The fact that the air near the sea contains salt is not due to the salt being volatile but to sea water aerosols generated by wind and waves.) The unpleasant and irritating smell emanating from selenium toner is not selenium but ammonia, which is also toxic, but - according to what I've read - not as dangerous in the long run. Also, it has the additional benefit of warning you of its presence by its smell, which selenium-contaminated dust fails to do.

Regards, Thomas Wollstein (

-- Thomas Wollstein (, March 28, 2001.

I don't think there is a thing as being too safe. My wife was recently diagnosed with lymphoma and I highly suspect it was her long- term exposure to fertilizers, pesticides and cleaning chemicals. She is an obsessive housekeeper and has spent many hours each week caring for her orchids and outside plants. We will never know for sure the source.

I have changed my darkroom habits dramatically. When I mix chemicals (powders), I use a mask(eyes and nose). When moving prints from one tray to another I either use my hands with gloves or plastic print tongs with rubber tips. Today, prescription medication comes in many forms such as ointments, gels, patches etc. These work effectively by osmosis and darkroom chemicals would as well. I wish I had been practicing "Safe Darkroom" many years ago.

-- Robert Bedwell (, March 29, 2001.

Thomas is right. Selenium compounds are not very volatile, so inhalation of the them is unlikely. But as someone else pointed out, spilled RST that dries can produce a powder that is easily inhaled.

And there are plenty of other darkroom chemicals that are volatile and potentially hazardous. So good ventilation is very important in a darkroom.

Se is very skin absorbable and toxic. Personally I would not handle prints in RST with bare hands.

However, I recommend NOT using latex gloves due to the very serious consequences of latex allergies. Latex allergies have lead to deaths in health care workers, IN THE HOSPITAL. I suggest nitrile gloves for most chemical usage. You don't have to throw them away after each use, but be VERY careful to keep the outside outside, and the inside inside. It is not normally recommended to wash gloves with your hands in them, because any flaw will allow the water to carry contaminates into the glove. However if you are working with liquid chemicals, this can happen anyway.

-- Terry Carraway (, March 29, 2001.

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