Does selenium toner expire?

[CarrieJoyce]

I've got a bottle of kodak selenium that's about 3 years old. Is it still good? What's the shelf life on that stuff? There are no dates on the bottle.

[Ken Nadvornick]

Welcome to APUG 'CarrieJoyce'...

This is a non-scientific, anecdotal observation, but I'm finally finishing up using a stock bottle of KRST selenium toner that I first purchased back in the mid-1980s. It sat around partially used and capped for several decades during a... umm... "pause" in my photographic activity, so to speak. It still seems to work fine for me. When it's finally gone I'll be replacing it with the new Ilford/Harman selenium toner. However, KRST is still available, if you prefer that.

Unless contaminated, I'd guess yours is fine.

Ken

[CarrieJoyce]

Thanks! Yeah, I've had a few "pauses" in my photographic activity... Life happens.

[Mike Wilde]

Mine I am pretty sure dates to the mid 60's and is still going strong.

The constituents are all inorganics as far as I know, and hence should not degrade.

It does contain ammoniumum thiosulfate, but I have yet to see any sign of the sulfur dropping out of KRST like it can do with old fixers that use it.

[nworth]

There is nothing much in most selenium toner formulas that would expire. Of course, it could go bad if it got contaminated. Like Ken, I've used stock KRST that was about 30 years old without problems.

[Michael R 1974]

I've read many times that it does not go bad, but I'm not sure why that would be. After all it contains fixer, and sulfite (presumably as a preservative ?). So why would it last so long?

[daleeman]

Back at Ohio Univ, our photography chair Arnold Gassen had us use it to tone our negs for long archival life. Has anyone else done this and if so, what percentages does one mix it at?

Lee

[Mike Wilde]

I would guess at 1+9 like one does for print longevity. It is but a guess.