Does selenium toner expire?

Discussion in 'B&W: Film, Paper, Chemistry' started by CarrieJoyce, Jul 16, 2011.

  1. CarrieJoyce

    CarrieJoyce Member

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    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.
     
  2. Ken Nadvornick

    Ken Nadvornick Subscriber

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    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
     
  3. CarrieJoyce

    CarrieJoyce Member

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

    Mike Wilde Member

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    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.
     
  5. nworth

    nworth Subscriber

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    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.
     
  6. michael_r

    michael_r Subscriber

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    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?
     
  7. daleeman

    daleeman Subscriber

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    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
     
  8. Mike Wilde

    Mike Wilde Member

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