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  1. #21
    Roger Cole's Avatar
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    Best disposal method

    I may go to Doremus' technique but what I've been doing with used selenium toner is just pouring it I to a bucket and letting the liquid evaporated, depositing the selenium, any remaining silver etc on the bottom and sides. Once it fills up (probably about 8000 years at the current rate...) or I quit printing, one bucket can be taken to a hazmat collection facility for disposal.


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  2. #22
    Maris's Avatar
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    Quote Originally Posted by Doremus Scudder View Post
    I never dispose of selenium toner. I replenish it, filter it and reuse it -- indefinitely. I have two gallon jugs of selenium toner of different strengths that have been going for about 10 years (maybe longer). No problems with toning activity or print longevity. I routinely do residual hypo and residual silver tests on my prints and they all pass with flying colors....
    Doremus Scudder has it right. The end point of selenium reactions in photochemistry is silver sulfo-selenide, the black(ish) precipitate, or selenium sulfide. Both chemical species are remarkably stable and inert. That's why selenium toning preserves silver based photographs. Neither silver sulfo-selenide or selenium sulphide are biologically dangerous in any credible scenario either by skin contact or ingestion short of attempted (but likely unsuccessful) suicide. Selenium sulfide is the active ingredient in anti-dandruff shampoo so just about 100% of the selenium entering a community sewage stream comes from this source. The selenium contribution from the increasingly rare home darkroom in an average community would be below notice.

    But replenish, filter, and re-use is definitely the best way to go.
    Photography, the word itself, invented and defined by its author Sir John.F.W.Herschel, 14 March 1839 at the Royal Society, Somerset House, London. Quote "...Photography or the application of the Chemical rays of light to the purpose of pictorial representation,..". unquote.

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