Could you at least take the time to define "trivial both in content and in testing"? I have a feeling that if you were to take the time you might find that 20 Mule Team Borax would pass the tests. There is no specific requirement for Chloride or Sulfate. I found it surprising that passing the carbonate test means that carbonate is less than about 1%.
Originally Posted by Photo Engineer
The foreword states that "This is one of a series of standards that establishes criteria of purity for chemicals used in processing photographic materials."
I'm of the opinion that what you are really saying is "Don't confuse me with the facts. My mind's made up."
I'm not saying you should use any particular brand or grade of anything. The cheap stuff does pass the test for iron. Whether its content of chloride and sulfate would cause it to fail the ammoniacal silver test, I do not know. Perhaps you could inform us on the basis of known specs in what ways the best is better than the technical powder for processing film.
All right, I'll describe trivial in testing first.
Carbonate test, add sulfuric acid to a measured amount of borate solution and if it fizzes it fails the test but if it does not, it passes. That is my definition of a trivial and rather useless test, chemically.
Trivial in content now. Halides and heavy metals are critical in some applications and these are not addressed fully, just a few as seen from your post. As far as solids are concerned, a visual inspection is all they ask for. This is trivial both chemically and in content or intent for the purpose at hand, which is photography.
Does that mean that you have in fact tested "the best" by those more stringent tests, or that you just don't trust the Photographic & Imaging Manufacturers Association, Inc. to know what is suffucient for film processing? You must have, at some time, tested 20 Mule Team Borax and "The Best" if you are so sure about the differences in purity.
Originally Posted by Photo Engineer
I have run qualitative and quantitative analyses on many materials. I would say that these are qualitative in nature and are not indicative of much. Also, as you mention in the original post, these are ANSI. Are they PMA as you now state? PMA does not define standards AFAIK. ANSI and ISO define the standards that Kodak uses.
I've been thinking of a different tack here. This is about Borax and developers but lets define Borax for all photographic uses.
It is used as a buffer in fixes as well as in developers. Now, we know that Potassium ion will 'poison' a fix. This is stated unequivocally in Mees, Mees and James and Haist. Therefore, for photographic use, a Borax buffer would have to include Potassium level as part of its specification.
Do you see my logic about looses specification and specifications intended for photo chemical use?
The printout I got says at the top that it was approved 2/20/82 and reaffirmed 5/12/98. Secreteriat: Photographic & Imaging Manufacturers Association, Inc.
It is part of a series of chemicals used for processing photographic materials. None of the grades of borax that I have seen specs for have even mentioned Potassium, and I have seen a lot of them in the past few weeks, including pharmaceutical grade. Did you really get a guarantee of no Potassium? How would we know where to get the "best stuff"? I see your point about specifications. I have not seen how you know you have satisfied your needs. Do you know for a fact that your borax has been tested for Potassium?
The ANSI Standard claims only to imply a consensus of those substantially concerned with its scope and provisions. It further states "Although the ultimate criterion for suitability of a photographic grade chemical is its successful use in an appropriate photographic use test, the shorter, more economical tests described herein are generally adequate.
It would be a good thing if instead of saying that what would keep one from using the technical grade as specified by the manufacturers must necessarilly keep one from using it for any photographic purpose, to tell us what we more mundane uses we might put it to in the darkroom, especially since that grade has passed the use test over many years in many different developers.
Lots of typos. Not much sleep last night. Sorry.
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.
We all know from watching the various CSI shows on the boob tube that identification of microscopic traces of anything is now a piece of cake.:p
A saturated solution of MC is clear as distilled water. I have no idea how much chloride-bromide it takes to fail the ammoniacal silver nitrate test. I am quite sure that a higher grade would be required for analytical work, but I'm also quite sure from my own long experience that for use in film and paper developers, MC is fine.
Now PE has thrown a new monkey wrench into the works. What if there is potassium in the MC and I want to use it to make fixer? First, I looked all through my copy of The Theory of the Photographic Process and could find no admonitions or even mention of the effects of potassium in fixer. Maybe there is a later edition than the third, but I think they would have known about it by then. But suppose we must avoid potassium in the fixer at all cost. How would it be removed from borax, especially if it is in the form of potassium tetraborate? Also, how much washing between developer and fixer would be required to prevent carryover from a potassium-containing developer, of which there are many? Perhaps PE was referring to color developer.
I must repeat my request that you guys also test what you buy to make sure you are getting what you think you got. I have used MC long enough to know it does what I expect of borax, but have you used it long enough to know that it does not do what you expect of it, or tested yours against MC to see if you could use it?
Mees, P 719, Mees and James, P 400 and Haist, Vol I, P 566 in which he states that fixers with Potassium salts are virtually useless. (Work of Frank and Schramm). Mees shows that K salts are roughly 4x slower as fixing agents.
So, I have found it in 3 places, besides having worked with Grant and others on some of this stuff.
Using Potassium Metaborate as a buffer in a fixer could paralyze its activity. A high percentage of potassium in Borate salts used to buffer a fixer might also slow it down or cause bad fixing.
A good stop or wash after a potassium containing developer will do a good job in preventing deterioration of the fix, but a standard test of the fixer will show either clearing time going up or silver halide being retained. Since we all check our fixer quality, this should not be a problem, right? :D
Patrick, you are questioning me on my home turf when you talk fixers! I learned from these people and many of the people that they refer to when I started at Kodak.