Murray Kelly
Member
Now you can use all the tubs of hardware store borax in your bath and not worry yourself if that kind of borax is good enough for photography! 
Murray

Murray
188g seems a lot of borax. Does it need all that to just buffer it? Or is it a matter of 'those damned dots'?
Murray
I think my city water in Newport News, VA had more stuff in it than this developer.
My Borax Project
SNIP)
Borax has 2 possible states of hydration, decahydrate and pentahydrate. If a 100 gram sample of pure borax has pentahydrate and decahydrate mixed, the assay will show a greater weight than 100 grams. If 5 grams of a 100 gram sample are the pentahydrate and the rest the decahydrate, no matter how purely the saple is composed only of sodium tetraborate and water of hydration, the assay will show 101.5 grams of the decahydrate. There is no way you can tell at time of collecting a sample from a large batch of pure mixture how much of each hydrate you are getting.separated from the solid at a low temperature, it will have a constant weight of borax per unit weight of solution at any (reasonable) higher temperature. The weight per unit volume will stay constant enough for most
SNIP
Finally I have a real question. Given what you have said, what would the difference in the pH be of (say) your P-C-Borax developer above using an unlikely but possible scenario that one had a box of pentahydrate versus a box of pure decahydrate and made the developer from one or the other?
Approximately 20g /litre would show a difference of how much pH?
My suspicion is that the single decimal place pH meter wouldn't help one distinguish the one from the other. Yes/no?
Murray
I was all set to process my 2kg of borax as you describe (except I was planning to return the supernatant to the boiler each time for the next 500g so's not to lose the 47g/l) when I went to Google and found the MSDS for both brands that I have here. Murray
BTW, Murray, what did you expect to gain by putting the supernatant liquid back in the pot? That contains all the garbage that was leached out of the good stuff. Reminds me of my daughter's idea for saving gasoline. She thought of putting a windmill atop her car driving a generator which would drive an electric motor to assist the gasoline engine.
Now, there's a difference! Not like the almost too close to call Microdol-X comparison in the other thread on the 'dead' metol.I'm posting the comparison that really counts, the one between SPF-3 and Rodinal 1+25. All I have to do now is find where I saved them.
They are "hybrid" photos, using a flat bed scanner at 600 dpi to read 11x14 analog prints. If you print them to 8x10, you should view them from about 6 ft to get proper perspective.
Now, there's a difference! Not like the almost too close to call Microdol-X comparison in the other thread on the 'dead' metol.
I have to say, tho, I've never used Rodinal that strong and don't know if dilution is a factor. The tonality matches but the detail isn't there. SPF-3 looks good to me.
Given the unusual solubility (amount and curve) my idea was to fractionally crystalise out the tetra and leave any more soluble contaminants in the supernatant. I didn't do it in the end. I merely weighed the plastic pots and contents, making a note under them and will reweigh when I need to open another one up for use. This assumes the contents were indeed tetra as stated on the MSDS to start with.
Murray
The molecule that entered as the pentahydrate carried 10 molecules of water with it. The molecule that entered as the pentahydrate carried 5 molecules of water with it. Now we have 2 molecules of Na2B4O7 floating around in 15 more molecules of water than we had before. There is no way we can tell which of the borate ions came in which which of the water molecules.
Why use 10g phenidone in 500 ml or 2g/100ml? Was it a typo or does this amount have a detectable different effect? In PC-TEA is only 0.25g/100ml.
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