Toxicity and risks of selenium toning

[Mainecoonmaniac]

While I might quibble with the designation, "extremely toxic substance," I certainly recommend handling selenium toner with utmost care. And, contrary to what has been mentioned above, I believe that selenium can be absorbed through the skin, albeit slowly. So, although Saint Ansel used his bare hands to tone with, do wear gloves or use tongs when toning, wipe up spills and wash trays and hands after the toning session.

I also recommend the practice of replenishing and reusing toner. I have a couple gallons that have been going for well over ten years; they still tone just fine. When toning times to achieve the desired tone become too long, simply add a bit of the toner concentrated stock solution to the working solution to increase its activity. Start small, it doesn't take much. Then, simply filter the working solution before and after use (coffee filter or the like) to filter out the black precipitate that forms. Replenishing and reusing toner is not only more economical and keeps you from discarding selenium into the sewer or septic system, it also has the advantage that the working solution smells less.

Best,

Doremus

Hi Doremus. Do you mix hypo clear into your toner?

 

[Doremus Scudder]

Hi Doremus. Do you mix hypo clear into your toner?

Absolutely not. The whole "mix-the-tone-with-hypo-clear-and-save-a-step" thing was promoted by Ansel Adams in his books; that's why so many have picked up the practice. However, this was from the days when not so much attention was paid to environmental safety and economy. People would mix the toner with hypo-clear and then toss it when the capacity of the hypo clear was reached, wasting a whole lot of toner and dumping it all down the drain into the sewer or septic systems. Keep in mind that hypo-clear only lasts about 24 hours once mixed and has a throughput capacity of only 20 8x10s per liter when used this way. I'd sure hate to toss my two liters of toner after only 20 11x14 prints went through it, or after a day had passed since I mixed it... Of course, you can still use your toner after the hypo-clear part has been exhausted; the selenium toner will remain active for much longer, there will just be no wash-aid activity.

Best practice these days is to use a separate hypo-clearing bath (wash aid or whatever; I mix my own) after the toner. For maximum capacity from your hypo clear, you should rinse after the toner for two minutes in running water. I just transfer prints directly from the toner into the hypo clear and take the reduced capacity into account (again, 20 8x10s per liter; mixing from scratch is fast and cheap). The hypo clear gets tossed at the end of the session, my toner gets filtered and stored for the next toning session. As I'm mentioned, I've got bottles of toner that have been going this way with occasional replenishment for way more than 10 years.

Best,

Doremus

 

[john_s]

And given that KRST contains lots of ammonium thiosulphate the wash aid probably isn't going to help the washing.

KRST also contains sodium sulphite which preserves thiosulphate and apparently oxidizes fairly quickly, I wonder if addding a bit of sodium sulphite to long lasting working KRST would be beneficial?

<excerpt from MSDS of KRST stock>
3. Composition/information on ingredients
Weight % Components - (CAS-No.)
55 - 60 Water (7732-18-5)
25 - 30 Ammonium thiosulphate (7783-18-8)
10 - 15 Sodium sulphite (7757-83-7)
1 - 5 Selenious acid, disodium salt (10102-18-8)

 

[RalphLambrecht]

Dear all,

I use selenium diluted 1 + 19 for toning, I wanted to ask you if there are valid risks for my health.
Today reading the instructions, after I had already toned prints in the past (I should have done this first), recommended using gloves, a mask, etc.

In Tim Rudman's book "Master Printing Course" he says that it is essential to use gloves and good ventilation only at higher concentrations, such as: 1 + 3, 1 + 1 or 1 + 2.

Cheers.

there is no risk to your health from the liquid toner if use3d according to the manufacturer's recommendations. There is a risk if mixing from raw dry chemicals due to inhaling the seleniumpowder; use the liquid toner instead.

 

[Mainecoonmaniac]

As I'm mentioned, I've got bottles of toner that have been going this way with occasional replenishment for way more than 10 years.
Best,

Doremus

That's amazing and economical. Thanks for the tip!

 

[Josh W]

I've been suggested to exhaust old Se toner with test strips & bad prints to get the Se out of it. Once it doesn't tone anymore dump it

 

[Andrew O'Neill]

When I selenium tone my kallitypes, I don't bother with gloves, as the dilution is 1+100...but I do have the ceiling fan on. The strongest I've ever used the toner was at 1+3 (intensifying negatives), then I would wear gloves and respirator.

 

[RalphLambrecht]

Dear all,

I use selenium diluted 1 + 19 for toning, I wanted to ask you if there are valid risks for my health.
Today reading the instructions, after I had already toned prints in the past (I should have done this first), recommended using gloves, a mask, etc.

In Tim Rudman's book "Master Printing Course" he says that it is essential to use gloves and good ventilation only at higher concentrations, such as: 1 + 3, 1 + 1 or 1 + 2.
use the liquid toner as instructed and there are no risks. there are risks if you make the toner yourself from selenium powder due to inhaling the powder; stay with the liquid toner4!
Cheers.

 

[pentaxuser]

In the Ilford Guide video the lady demonstrator makes a 1+3 dilution of Selenium, so a fairly strong one but uses no respirator. She does have gloves and goggles to stop splashes getting onto her hands and into her eyes but it seems to me that given that there appears to be no breathing problems at 1+3 then if the right vessels are used for mixing and pouring such that even small splashes are preventable and you are not leaning into the vessel as you pour and mix the stuff then splashes are extremely unlikely

pentaxuser

 

[removed account4]

I've been blue toning in horse shoe crab blood, comes out great.

 

[pentaxuser]

I've been blue toning in horse shoe crab blood, comes out great.

We also have "blue blooded" creatures in England. None live under water but some still live in large Stately Homes. Most of their blood was drained literally by the Great War 1914-18 and then metaphorically by death duties. Some whose ancestors used to kill African and Indian(sub continent of India that is ) animals such as lions and tigers have now opened what we call Safari Parks where the same animals have to be properly looked after

Life is full of ironies

pentaxuser

 

[Sirius Glass]

If one wants to avoid the toxicity of selenium, do not drink it.

 

[MattKing]

If one wants to avoid the toxicity of selenium, do not drink it.

It is the powder and the dried residue of any missed drops that are often the greatest concern - you want to avoid inhaling the dust.
Gloves and glasses will protect you from the liquid. And if anyone needs to be told not to drink it, I'm surprised they got this far.

 

[Doremus Scudder]

I've been suggested to exhaust old Se toner with test strips & bad prints to get the Se out of it. Once it doesn't tone anymore dump it

If you must discard it, this is a good way to make sure that the solution you eventually dump down the drain is very weak.

Replenishing works great and saves money and the environment, so don't dump your toner unless you have other reasons.

Best,

Doremus

 

[Doremus Scudder]

When I selenium tone my kallitypes, I don't bother with gloves, as the dilution is 1+100...but I do have the ceiling fan on. The strongest I've ever used the toner was at 1+3 (intensifying negatives), then I would wear gloves and respirator.

If one wants to avoid the toxicity of selenium, do not drink it.

Selenium is absorbed through the skin. So, don't drink it and don't stick your bare hands in it.

Best practice is to wear gloves when toning or use tongs and rinse any splashes with running water immediately. Goggles are a bit overkill unless you tend to splash around in the toner a lot, but a good idea if you do and for Ilford to demonstrate with them (for liability issues).

As mentioned, it's also important to clean up any spills quickly and well so they don't dry and the powder become airborne.

The largest problem with fumes from selenium toner is the ammonia; it can irritate and is downright unpleasant. Good ventilation helps. Selenium won't evaporate or aerosolize, so a respirator really isn't needed. FWIW, replenished toner has almost no ammonia odor at all and still tones just fine.

The real danger in exposure to selenium is from the powdered selenium reagent used to mix toners from scratch. A respirator, goggles, gloves, apron, vent hood and excellent ventilation should be used for mixing your own. Or mix outdoors with appropriate protective equipment.

For my part, I'll stick to buying the liquid concentrate from Kodak or whomever. I don't need powdered selenium sitting on my shelf.

And, eat those Brazil nuts in moderation, especially if you're toning without gloves!

Best,

Doremus

 

[Andrew O'Neill]

Selenium is absorbed through the skin. So, don't drink it and don't stick your bare hands in it.

Best practice is to wear gloves when toning or use tongs and rinse any splashes with running water immediately. Goggles are a bit overkill unless you tend to splash around in the toner a lot, but a good idea if you do and for Ilford to demonstrate with them (for liability issues).

As mentioned, it's also important to clean up any spills quickly and well so they don't dry and the powder become airborne.

The largest problem with fumes from selenium toner is the ammonia; it can irritate and is downright unpleasant. Good ventilation helps. Selenium won't evaporate or aerosolize, so a respirator really isn't needed. FWIW, replenished toner has almost no ammonia odor at all and still tones just fine.

The real danger in exposure to selenium is from the powdered selenium reagent used to mix toners from scratch. A respirator, goggles, gloves, apron, vent hood and excellent ventilation should be used for mixing your own. Or mix outdoors with appropriate protective equipment.

For my part, I'll stick to buying the liquid concentrate from Kodak or whomever. I don't need powdered selenium sitting on my shelf.

And, eat those Brazil nuts in moderation, especially if you're toning without gloves!

Best,

Doremus

I've been using it for thirty years and have enough sense to not soak my hands on it, let alone drink it. Who the hell would do that?? Ansel Adams requested that his tissue be examined for selenium after he died. They found nothing.

 

[pentaxuser]

Ansel Adams requested that his tissue be examined for selenium after he died. They found nothing.

I fear I dare not make the same request of the post mortem examiner in respect of my tissue for Speyside whisky in case they find something rather more damning, Andrew

pentaxuser

 

[wyofilm]

I've been using it for thirty years and have enough sense to not soak my hands on it, let alone drink it. Who the hell would do that?? Ansel Adams requested that his tissue be examined for selenium after he died. They found nothing.

Then they weren't looking well enough. Selenium is a micronutrient and has biological roles in humans. I've even fed elevated amounts of Se to cattle deficient in it.

 

[Andrew O'Neill]

Then they weren't looking well enough. Selenium is a micronutrient and has biological roles in humans. I've even fed elevated amounts of Se to cattle deficient in it.

Well, it was1984...

 

[Andrew O'Neill]

I fear I dare not make the same request of the post mortem examiner in respect of my tissue for Speyside whisky in case they find something rather more damning, Andrew

pentaxuser

 

[MattKing]

I fear I dare not make the same request of the post mortem examiner in respect of my tissue for Speyside whisky in case they find something rather more damning, Andrew

pentaxuser

Don't worry,
The report will merely say:
"This explains so much!"

 

[Andrew O'Neill]

I should add that I have only ever used KRST. I've never mixed selenium toner from scratch, nor would I want to.

 

[Michael Firstlight]

With N95 masks and gloves so prevalent these days and Heppa air cleaners fairly inexpensive - why not just take such precautions? Is it that onerous? Ideally one also has an exhaust in the darkroom.

 

[AgX]

In the Ilford Guide video the lady demonstrator makes a 1+3 dilution of Selenium, so a fairly strong one but uses no respirator.

Why should she use a respirator?
Against what?

 

[pentaxuser]

Why should she use a respirator?
Against what?

Quite so and that was the point I was trying to make. If llford and presumably the demonstrator do not feel the necessity of wearing a respirator in a public video of its own product then see no reason why a respirator is required but clearly some do and that's fine but for a healthy specimen of Joe Public there would appear to be no reason

pentaxuser