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  1. #1

    Join Date
    Aug 2005
    Multi Format

    Selenium Toning w/ KHCA

    I was reading where someone said that on a box? of KHCA it was reccommended to add KHCA to KRST when selenium toning...

    Can someone provide an explanation for this combination?
    perhaps even a scan of those instructions?!!

    I do not recall seeing it on any of my pkgs of KHCA...
    Did something change?

    What is the logic behind the mixture?
    Any opposing views?


  2. #2

    Join Date
    Sep 2002
    Oregon and Austria
    4x5 Format

    Many used to use selenium toner mixed with the washing aid to eliminate a step in the processing. However, this is wasteful; the wash aid exhausts much more quickly than the selenium toner. If one wanted to keep the advantage of the wash aid, one would have to discard a lot of active toner, something I find not only wasteful, but environmentally irresponsible. There are enough heavy metals contaminating our waters and soils (not to mention our food!) already.

    I use my selenium toner over and over by 1) adding more stock solution to replenish and 2) filtering out the black precipitate that forms. I have two one-gallon containers with different working dilutions that have been going strong this way for over three years. By re-using the toner, the selenium I buy goes into the prints, not the waste water. My total discarded selenium, excepting that that is washed out of toned prints, is, for practical purposes, zero.

    The wash aid I use in a separate step, immediately after the toner. I find that it does not add a lot to my overall processing time since I usually tone large batches, and there are prints in the toner and the wash aid at the same time except for the very last few.

    My recommendation: Save your toner and re-use it. It's cheaper as well as more environmentally friendly. Use your wash aid separately, paying attention to the capacities so you do not overuse it.


    Doremus Scudder




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