Useable time on Seleniumgreenspun.com : LUSENET : Large format photography : One Thread
I recently began using selenium to tone my prints. Made up half a gallon of the stuff and am wondering how long or for how many 11x14 prints the solution is useable.
Thanks in advance for your comments.
-- Robb Reed (firstname.lastname@example.org), October 10, 2000
See www.greenpun.com/bboard/q-and-a-fetch-msg.tcl?msg-id=003s N8
It's the B&W printing board, look about ten questions down. This subject is addressed.
-- Ted Davis (email@example.com), October 10, 2000.
I couldn't get the above link to work, so to save time I've copied my answer from the above-mentioned thread. Here it is (pardon my presumptiuousness):
I have come to the provisional conclusion that selenium toner can be used practically indefinitely. As the toning solution becomes weaker and the toning times too long, a small amount of the stock can be added as a sort of replenisher. After long use or storage a black precipitate can form. This can easily be filtered out with filter paper such as a coffee filter or the like. The same solution can be used, stored and replenished for years. This eliminates the environmental concerns and disposal problems entirely. I have one gallon of solution that has been going for almost 3 years now. I originally had concerns that by-products might build up in the toner solution, but I now believe that any by-products (e.g. thiosulfate compounds) precipitate out and are removed with filtering. I test my prints regularly for residual silver and hypo and they always pass with flying colors. Instead of dumping that old toner down the drain next time, just add a few ounces of stock and keep using it and you'll see what I'm talking about. No use being irresponsible if you don't need to be.
-- Doremus Scudder (ScudderLandreth@compuserve.com), October 11, 2000.