Now on to your second paragraph. Indeed Potassium Alum is used in fixes and it slows down fixation and causes silver retention. This is why hardening fixes began using ammonium salts to take into account the synergy between thiosulfate and ammonium ion. In effect, you can balance out the effect of potassium but only to some extent. Elimination of the potassium will allow even faster fix rates and better fixation.
As for the use of borax in fixers, they are used in many alkaline fixers as a buffer. If the level of potassium were to be too high, it would negate the effect of having an alkaline fixer entirely and make it as slow as an acidic fix of much the same formulation. Washing would probably be slowed as well.
As far as having references here, yes I do. I have hundreds of textbooks on photographic emulsion making and processing, books on theory and books on system design. So, when I wrote that note giving references, I had 3 textbooks open next to me to those pages reading exactly what was said.
And, I have done lab experiments, some of them with Haist standing next to me either guiding or observing, invovling these processing principles.
And, since we have no spec for potassium in tetraborate or boric acid in the standard you published, we don't really know how it would work in some instances.
I don't even remember how this got into a pissing match. All I wanted was some clear idea why 20 Mule Team Borax was not as good as so-called photo grade for my purposes and those I propose. I could get no specs for whatever grade you use for allowable soluble impurities. I could find lots of guaranteed specs for sodium tetraborate pent- and decahydrate, but never got an answer as to which one you would accept for practical use in developers. I have never proposed a formula for a fixer. I have never proposed a developer formula that I have not used myself. Until recently, I never used significant quantities of borax that I told anyone about.
I do not understand why I am accused of confusing others and am told to keep my nose out. You are the one telling others that 20 Mule Team Borax has impurities that keep it from being properly used for developers without telling them what to use in its place except to get it from a photochemical dealer, also unspecified, who might in fact be repackaging the same produce you get in the grocery store.
When I proposed a way to reduce soluble impurities by a factor of 16 or more you had a lot of "Yes, but"s. I think that AR grade is an unnecessary cost for most of us, and that for most of us who might want a small amount of more pure borax, the differential solubility method will work quite well. As I said, I did quite well in the Chemical Engineering Lab course. I was simply unable to handle courtship, being principal oboist for the University-Community Orchestra, and a 21 credit hour course load including the seond semesters of both Physical and Organic Chemistry lecture and lab courses all at once. I was not the first, nor the last to have that happen. I could have repeated Organic chemistry but chose instead to change to Aeronautical Engineering. If that makes me an idiot, then at least I am a well educated idiot.
Photo Engineer;565289]"Now on to your second paragraph. Indeed Potassium Alum is used in fixes and it slows down fixation and causes silver retention. This is why hardening fixes began using ammonium salts to take into account the synergy between thiosulfate and ammonium ion. In effect, you can balance out the effect of potassium but only to some extent. Elimination of the potassium will allow even faster fix rates and better fixation."
Yes, but...
I never proposed the use of potassium salts in any fixer.
"As for the use of borax in fixers, they are used in many alkaline fixers as a buffer. If the level of potassium were to be too high, it would negate the effect of having an alkaline fixer entirely and make it as slow as an acidic fix of much the same formulation. Washing would probably be slowed as well."
IIRC, I asked what would borax be doing in an acid hardening fixer.
"As far as having references here, yes I do. I have hundreds of textbooks on photographic emulsion making and processing, books on theory and books on system design. So, when I wrote that note giving references, I had 3 textbooks open next to me to those pages reading exactly what was said."
OK. I believe you. But it still remains difficult to see how trace amounts of potassium chloride or even potassium borate apply to those comments.
"And, I have done lab experiments, some of them with Haist standing next to me either guiding or observing, invovling these processing principles.
And, since we have no spec for potassium in tetraborate or boric acid in the standard you published, we don't really know how it would work in some instances."
I didn't publish it, I repeated it from the ANSI-PMA Standard for borax for photographic use.
Ridicule is the lowest form of argument. Argument from authority is not much higher when other bases are available.
You asked why I thought that the standard you published for Borax was trivial and useless for photo products. I pointed to the fact that it had no standard for presence of potassium salts and was therefore unsuitlable for application to fixers.
You questioned the authority on fixers and indeed the use in fixers, or in fact, any problem with the use of potassium alum in fixers.
So, I iterated the problems and gave the literature references which you also questioned. Then, I posted the data from the reference itself.
So, by line chapter and verse, I have tried to point out the error in the poor standard you posted, and you replied with what was essentially "yes, but" or "I can't find a reference".
So, that is how this took place. I questioned the standard and stated my reasons for both developers and even more importantly for fixers. You refused to accept my answers as being either factual or correct, and so I gave instances to prove my case.
PE
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No, the problem was not my refusal to accept answers, it was my refusal to accept your interpretation of the problems. I am quite sure you provided accurate answers to the problems you posed, but they were not all the problems I wanted solved. If you had from the start identified your source for the borax you recommend and a set of specifications for it so that anyone else could search for other sources of equal product, I would have been happy. I still might have proposed a way to make cheaper product work for special occasions, who knows?
As it happens, all the impurities you have supposed might be in what I now fondly call "Mule Crap" are either very much more soluble than borax or insoluble. That includes all the likely potassium compounds. That means they may be reduced by the method I described to whatever percentage might be desired by successive solution and filtering. If you use the last solution as the product, you can dry it to powder if desired or use it as a known percentage solution. Now if I just knew the specs you require for your particular work, I could devise an engineering approach to providing it from cheap stuff and you could decide whether it is worth the trouble. I should remind you that the high quality stuff is not always available in small quantities, so you might have to buy a 50# bag to get a few ounces.
I'm going to lean back, relax, and let you teach us all chemistry. Have fun.
In the meantime consider whether you are doing a real service to quality photo processing or are merely putting a means into peoples hands to play around with by your use of pool and laundry chemicals and the use of volumetric measure of solids.
Remember, if some newcomer to photography follows any of your advice and gets a bad result, you may discourage him from continuing. This is the responsibility that I feel with every post I make.
There are two levels here, fun photography to see what can work, and serious photography in which we want a good, repeatable process.
I can tell you what must not be in Borax except in very tiny trace amounts.
Heavy metals
Halides
Potassium salts
Iron salts
Copper salts
Phosphate salts
Sulfate salts
Insoluable materials (dirt, sand and etc...)
Those are at the top of my list and should be absent from good Borax. And, high quality stuff is always available in small quantities. I can get 100 - 1000 grams of analytical or reagent grade Borax any time I wish. It is available on-line.
You asked why I thought that the standard you published for Borax was trivial and useless for photo products. I pointed to the fact that it had no standard for presence of potassium salts and was therefore unsuitlable for application to fixers.
You questioned the authority on fixers and indeed the use in fixers, or in fact, any problem with the use of potassium alum in fixers.
So, I iterated the problems and gave the literature references which you also questioned. Then, I posted the data from the reference itself.
So, by line chapter and verse, I have tried to point out the error in the poor standard you posted, and you replied with what was essentially "yes, but" or "I can't find a reference".
So, that is how this took place. I questioned the standard and stated my reasons for both developers and even more importantly for fixers. You refused to accept my answers as being either factual or correct, and so I gave instances to prove my case.
PE
I have tried to tell you that I did NOT publish the ANSI-PMA standard. I did not question the literarure references except to note that one of them is not in my copy of the third edition of "The Theory....." on the page you quoted or anywhere else. And it has not appeared there by some miracle since then. And instead of replying with the date of printing of your copy, you chose to ridicule my intelligence and my knowledge of chemistry. I'm sure your copy has a later printing date than mine, which is the fifth printing of the third edition.
I don't mind your questioning of the ANSI Standard, but please don't blame me for it. It specifically applies to most common photographic uses, and has more disclaimers than the stuff that is supposed to make a utility pole out of a penis.
I got the ANSI specs for Photography chemicals sodium tetraborate, pentahydrate and decahydrate, 3 pages ata cost of about $21. In a nutshell, the summary of requirements is:
Assay, Pentahydrate or Decahydrate......101% min, 105% max.
Heavy metals (as Pb)......0.002% or 20 ppm.
Iron (Fe)......0.003% or 30 ppm.
Carbonate......To pass test.
Reaction to Ammoniacal Silver Nitrate.......to pass test.
Appearance of solution........to pass test.
The tests are described in great detail. Kirk or PE could perform them. Most of us have not the equipment nor the skills to perform them.
It appears that the specs would be met or exceeded by the NF grade described at www.borax.com, and the SQ grade would come very close.
You will notice that the minimum assay is greater than 100% and less than 105%.
Linear Mode
