Pat - I broke down and got the specification yesterday as well. But I only had to pay $17 from ANSI online!
Originally Posted by gainer
They are trivial tests! Nessler tubes in fact. (You have to work at a lab that has been in business for many decades to find a set of Nessler tubes. BTW, I just found a set of Nessler tubes in the lab last week!)
And I too was disappointed that ANSI was not more interested in the specific analytes we've been debating about for the last few weeks.
So I think the lesson to be learned here is found in the second paragraph, right after the line you quoted above:
"Although the ultimate criterion for suitability of a photographuc grade chemical is its successful use in an appropriate photographic use test, the shorter, more economical tests described herein are generally adequate."
What that tells me is that the ANSI spec is generally sufficient to descriminate between a grade that is useful in photography and a grade that is not sufficient for use in photography.
But, as PE points out, the real test is will the material work in the desired use. Buying a better grade than technical, like the NF (National Formulary) grade or especially the SQ which is very low in chloride, sulfate, and iron, guarantee that it would be suitable for all photographic purposes. (See http://www.borax.com/products1.html to find info on the grade Pat has been talking about.)
The only catch here is the SQ is a nuclear grade and is used for quenching runaway nuclear reactions. I but you would pay through the nose for that stuff. And no wonder it's so clean - you don't want to crap up your nuclear reactor with regular mule crap!
So did out those dusty, old Nessler tubes and get testing on your 20 Mule Team tech grade and show us that it does past the ANSI spec. I think it might pass all but the "reaction to ammoniacal silver nitrate" and maybe the "Appearance of solution" test. And that last one you can certainly do and let us know.
PS - if you need a set of Nessler tubes, here's some on eBay right now:
http://cgi.ebay.com/NIB-12ea-Nessler...sid=p1638.m118 only $15 for 12 plus shipping.
Last edited by Kirk Keyes; 12-28-2007 at 12:26 PM. Click to view previous post history.