Selenium Life

[jeff_buckels]

I use selenium (Kodak Rapid Selenium) at 1:3 for intensifying

negatives. It works. Anyhow, once in the diluted working form, how

much use do you figure you can get out of it? How long do you

figure it will store? Somebody on this list suggested "pretty much

indefinitely" etc., and I got a lot of use out of about 750ml of it,

but then it lost potency. Comments? -jeff buckels

[mark_sampson]

Basically, it will work until it doesn't, like developer. Since no one advocates reusing the toner, there are no specs. You are in somewhat uncharted territory, but it stands to reason that a strong solution like 1:3 would not be exhausted by a sheet or two. I've never re-used toner, but you could run a test by using it until you can't see a change- although that would be easier to see on paper than on film.

[eugene_singer]

Jeff, when Kodak Rapid Selenium Toner stock solution is diluted, the shelf life begins to diminish. However, I have a well-sealed one gallon Rubbermaid container of a 1+19 working solution that was mixed with distilled water. It is over three years old, and is still useable for toning prints. I place the completely fixed print into the toning solution after giving it a long water rinse. When the toning process is completed, I bathe the print in hypo clearing agent, and, then, give it a final wash in the archival washer. Occasionally, I filter the Selenium toner solution through a coffee filter to remove the black precipitate, and, then, top it off with some fresh KRST stock solution. The stuff seems to last indefinitely, providing that it is not contaminated with hypo clearing agent or fixer. It's getting more expensive to use, and I don't like flushing it into the sewer system.

[michael_alpert1]

Jeff,

 

I am not sure if Mark understands your question. Everyone advocates reusing selenium toner. At 1:3 it should be fine after years of use. Dilute it with distilled water, and use a separate tray of fix-remover before a final wash. Always use gloves or tongs. Selenium can hurt you. And it is not good for the environment either---another reason to reuse it for as long as it is viable.

[carl_weese]

If you dilute selenium toner with a washing aid, as is sometimes

recommended, it will have zero shelf life. Dilute it with plain water

and it will last until it wears out. Filter as needed.

[nguyen billy kok]

SO<

 

Why exactly do some experts recommend diluting the Selenium toner in a wash aid such as Perma Wash, and others recommend diluting the Selenium in plain water. Which works best and why dilute it wash aid, just wondering...

Nguyen "Billy" Kok

[eugene_singer]

"Billy", those "experts" made their recommendations in the past, when Kodak Rapid Selenium Toner was not as expensive and wasn't considered to be an environmental hazard. Mixing KRST with Hypo Clearing Agent, instead of water, was done to save the time and the extra step of clearing after fixing. Mixing them together eliminated the need for a separate clearing agent bath. However, the KRST + HCA solution was usually discarded after one darkroom session. We now have come to the realization that KRST works the same whether it is mixed with HCA, or water. However, when KRST is mixed with distilled water it lasts much longer and can be re-used over, and over again. Just make certain that the film or paper that is placed in the KRST solution has been properly fixed, treated with HCA, and completely rinsed so that it does not carry any fixer or HCA into the KRST bath. Since KRST contains ammonium thiosulfate (rapid fixer), the film or paper needs to be treated in HCA (again) after toning. Then it can go into the final wash.