selenium precipitate

[RJS]

Over a period of maybe a year my selenium toner mixed with tap water has precipitated out a great deal of translucent appearing filament like stuff so it is unusable. Does anyone know what is causing this? Will mixing with distilled water help? The toner was mixed 1:9 if that makes a difference and stored in my darkroom.

 

[Rich Ullsmith]

Strain it through a paper towel or coffee filter (or not), and fuggedaboudit. Really.

 

[RJS]

I tried that. I think all the active stuff was in the precipitate as it didn't do any toning.

 

[Dan Henderson]

At the risk of exposing my ignorance, here is what I think I know about selenium toning: when a print is immersed in selenium toner, the selenium bonds with the silver to become silver selenide, which is more stable. So each time a print is toned, some of the selenium is removed from the solution. If you have been using the toner for a year, I suspect this is what has happened.

I believe that David Vestal recommends adding a little bit of selenium concentrate to the toning bath each time it is used to replace the selenium used during the last session. He also recommends keeping the bath for a long time, occasionally filtering out the sediment. That is what I have been doing for awhile, also adding a capful of Hypo Clear each time.

But if yours is that far gone, maybe you would be better off starting with a fresh batch.

 

[RJS]

I'm sure your (Dan) information is good. My problem is that I have not used the solution much, perhaps six or eight prints over the year, and what I had was not just a bit of sediment but a HUGE amount of the stuff I described. After filtering I tried using the remaining solution and after perhaps ten minutes there was no noticeable difference in the print. I have made a fresh batch, but at the price of Kodak toner at my local store ($40 for a large bottle - all they carry) I am a bit reluctant to throw it out after so little actual use.

 

[Rich Ullsmith]

If your paper is not responding in an exuberant manner-- as compared to prints from the same toner, a year ago-- I would consider a few things.

What papers did you tone last time, compared to this time?

Was the temperature comparable?

Some bromide papers tone slowly and coldly over long periods of time, particularly if the toner is weak.

 

[RJS]

Unfortunately it's the same paper - same box even. I haven't been able to print for a while and am just getting back. Everything else seems to work ok - it's just kind of irritating to read of people using and re-using their toner and finding I must have screwed something up and don't know what. The paper is the ubiquitous fiber base MGIV. Temp is room temp - I have an air conditioner (this October has been ovenlike) but if I can stand it the toner should. Thanks for the suggestions.

 

[skahde]

In my own experience diluting the toner with distilled water improves its keeping properties. Adding a pinch of borax further improves it but will also slow down the toning the more you add.

best

Stefan

 

[George Collier]

I have been Selenium toning for many years myself, and for a long time, toned a big batch and threw the stuff away, a couple of times a year. Then I read on APUG about re-using.
I made a gallon of working solution, 1:20, with tap water, and a teaspoon of Kodalk (an old Fred Picker recommendation - must be like the borax mentioned by Stephan). Anyway, I toned 8 11x14 prints of Forte Fiber MG5, they toned well in 6-8 minutes (nice blacks, hint of brown). I started another batch (the same day, right after the first batch) and got almost no color change after 8-9 minutes. I added a small amount of stock, and they came up fine. I was surprised at this, since folks seem to get a lot more life out of the working solution.
With the dilution I describe, does this seem right?