selenium toner used up?

[dfoo]

How can you tell when your toner is all used up? Is there an easy way to find out besides "it didn't tone very well"?

 

[thefizz]

If the smell of ammonia has died off, then its exhausted.

 

[brian steinberger]

I can tell sometimes when silver colored flakes start coming out of the bottom of the bottle. Also it'll tone much much slower. It's easier to only run a certain number of prints through a working solution, keep track, and dump each time. Consistency is key.

 

[dfoo]

Any idea of the capacity of 2L of 1+9 selenium toner?

 

[brian steinberger]

I'd say around 25 sheets per liter. So about 50 sheets for 2L.

 

[Doremus Scudder]

I've posted about this often. I find it more economical and certainly more environmentally responsible to replenish working solutions of selenium toner. When toning times become too long, simply add a bit more concentrate. I have batches of toner that have been going for years this way.

Selenium toner works by depositing selenium onto the silver parts of the image in the print. As the amount of selenium in the toner becomes less, the toning times get longer. When toning times get very long, there is very little selenium in the solution. This is the time to replenish, or to discard it, if you decide to. Don't discard selenium toner that is still active. Save it and use it later. It keeps well for long periods. Usually, there is a black precipitate that needs to be filtered out before re-use, but this is easy to do and does not affect the toning.

The toning speed is the only way to tell if toner is exhausted or not. However, a toner that takes a long time to tone one paper may work very fast on another. Some papers just require higher strength toning solution to tone well. It has been my experience that the ammonia odor of the toning solution disappears long before the toner is exhausted; if the prints are still changing color, the toner is just fine.

When you do discard selenium toner, try to make sure it is very exhausted so that as little selenium as possible remains in solution. The best way to do this is to tone prints until the toning times are very long, then toss a few scrap prints into the toner and let them sit overnight. Then dump.

We should all be aware of the fact that municipal water-treatment plants do not remove selenium from the effluent stream. It usually concentrates in the sludge, along with other heavy metals. It's a good idea to keep our impact to a minimum.

Some advocate using exhausted selenium toner as fertilizer for flower gardens... If indeed the plants can use it, it would be a good way to avoid having to dump it. I certainly wouldn't recommend using it on vegetables, though.

Best,

Doremus Scudder
www.DoremusScudder.com

 

[Marco B]

If the smell of ammonia has died off, then its exhausted.

I have used selenium toner no longer giving of any really perceptable smell of ammonia for over a year without issues. And yes, it still toned, as witnessed by colorchange!

So I guess smell is not the best indicator...