I'm running out of my stock of borax. Thanks Elia
Their's will probably come from the same grade that you buy at the supermarket. How many manufacturers of this product are there? Suppose you were a retailer like PF. How many different grades could you get if you tried?
Thanks to all for your answers!
I suspect that the photografic grade is just the name and
in reality the household borax is the same stuff. Elia
Their's will probably come from the same grade that you buy at the supermarket.
Suppose you are right and the 20 Mule Team Borax is not what they claim, 100% sodium tetraborate decahydrate. When you buy it from Photographers' Formulary do you get any assurance that their's is in fact 100%? Does anyone in APUG have evidence that using 20 Mule Team borax has caused a problem in any of the many recipes that call for borax? Do you know the tolerance for error in any of these recipes? Can you supply evidence, personal or published, that ordinary grocery store borax is not good enough? As for teaspoon measures, have you tested those for consistency of weight or effect on photographic solutions? I have, long ago, and reported my results in an article for Petersen's Photographic (April, 1973) called "Kitchen Tested Soups". Kodak's instructions for those who want to mix their developers from scratch is to have a scale or balance good to 0.1 grams.
Researchers like PE need to know such things as tolerances, deviations from experimentally determined optima that will not cause noticable difference in performance, if their discoveries are to be put to practical use. You know for fact that as soon as one opens a package of dry ingredients to mix a developer, the ingredients are likely to be changed, and who knows what changes will occur when local water is used to mix them. What specifications would Kodak put on an order for borax, or sodium sulfite, or hydroquinone, or Metol for packaging the components of D-76?
I have a cheap timer from Radio Shack and a metronome. The timer does very well, thank you, for measuring time of development to the second if needed, and the metronome is quite good for timing exposures under the enlarger.
I have noticed a difference with Borax.
Many years ago I was trying to put together a solution, the only Borax I could get my hands on was some from a hardware store, fine I thought. Well not quite!
I was mixing a film developer, cannot remember what but if say it was D76, I would only have used 2gms for 1 litre.
What I found was that what I dropped in, didn't all go into solution. Eventually I figured it must have been impurities, so I finished the solution, cooled it, then filtered out the solids.
As far as I know the solution developed the film alright, otherwise I would have made a some warning notes for myself.
Currently, I use Analytical reagent grade Sodium Tetraborate, with a purity of 99.101%, for my film developing solutions.
I wouldn't really know how much difference, cost wise, this purity is, as I am on the last of two large bottles I bought in the late sixties.
Mick.
Labels are strange things.
IMHO, borax is the thing we should worry about the least, as in most recipies + or - 10% won't make a noticable difference. The concentration of the sodium borate will affect the local rate of change of pH more than the equilibrium value.
Like ones that tell you something is 100%. Don't believe them. They are not looking hard enough to find the impurities.
Mick's AR grade is certainly more believable - to get to AR grade it was most certainly purified more that Borax that was hauled by a 20 mule team, and even that extra purity could not get it to 100%.
So, Pat, why are we supposed to beleive that your inexpensive grade of borax is actually 100%?
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