PDA

View Full Version : Useable time on Selenium



Robb Reed
10-Oct-2000, 19:30
Gents:

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 us eable.

Thanks in advance for your comments.

Robb Reed

Ted Davis
10-Oct-2000, 22:27
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.

Doremus Scudder
11-Oct-2000, 08:44
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.

Regards, ;^D)