[pure-silver] Re: I say Ammonium you say Potassium
----- Original Message ----- From: "Eric Nelson" <emanmb@xxxxxxxxx> 
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Monday, August 20, 2007 11:11 PM
Subject: [pure-silver] I say Ammonium you say Potassium



In my Darkroom Cookbook as well as Blumann's book,
ammonium persulfate is called for for Nelson Gold
toner.
Is potassium interchangeable here?  I found it listed
here.  http://www.jackspcs.com/t21.htm

Eric
I checked both the Kodak and Agfa versions of Nelson's. They are identical to the patent and call for Ammonium Persulfate. Its possible that the cation is not important, one would have to experiment to find out. Nelson states in the patent that the exact action of the Persulfate is not known (c.1930). Ammonium Persulfate is also called for in Kodak reducer R-5. 

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx 
=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your 
account (the same e-mail address and password you set-up when you subscribed,) 
and unsubscribe from there.

Other related posts: