Borax Project

Quote:

---

Originally Posted by gainer

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

Quote:

---

Originally Posted by Murray Kelly

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 borate part of decahydrate and pentahydrate are identical. The difference is in the amount of water of crystallization. A saturated solution of either one at a given temperature contains exactly the same number of Na2B4O7 molecules. Once you have a saturated solution and have decanted the clear liquid, there is no point in trying to recrystallize the contents, because you are then back at the beginnibg. You still are not certain which of the crystals are pentahydrate and which are decahydrate. You still have to weigh the crystals to make any use of them, whereas the saturated liquid has a known content of the decahydrate per unit of volume and can be measured out with a graduated cylinder.

The terms "pentahydrate" and "decahydrate" have no meaning in solution. However much water of crystallization was taken into a borax solution becomes part ot the solvent water. All you have in solution is Na2B4O7 molecules and H2O molecules. 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.

Sorry - confusing my pentas, decas tetras etc. It's all greek to me.:rolleyes: Thinking metaborate. More greek.
I dunno how it's done commercially but I'd presume if there's excess water the deca will form. Commercially it's cheaper to ship 3/4 ton of penta than 1 ton of deca and deliver the same amt. of borate. Therefore one might be led to suspect there is some contamination of deca with penta regularly since it's in the system.
"You still have to weigh the crystals to make any use of them".
Don't think you meant one could tell the difference by weighing the crystals. If you did I don't see how. Naturally one weighs crystals - how else?
Is this one of Plato's Dialogues?
Murray

In low huidity it shouldn't take much heat, but a lot of tumbling, to change the deca to penta. Whatever you start with, it's just as easy for me to put enough in a pot of water so that not all dissolves, decant the clear liquid, and note the temperature. As long as you keep it at that or higher temperature, your solution has a fixed % of the equivalent of sodium borate decahydrate. If you can't find the chart at www.borax.com I can send you a copy.

Metaborate is another conundrum. It has two molecular weights which are identified as 4-mole and 8-mole, leading one to believe that these are states of hydration. However, one ghanges to the other in a closed container above a particular temperature and back again as the temperature reduces, obviously with no change of water content, so it is only of academic interest.

Quote:

---

Originally Posted by gainer

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.

---

I goofed and no one took me to task! What is the World coming to? The underlined word should, of course, have been "decahydrate".

Now I have to worry that I don't expand the goof like the editorial correction to a newpaper article: "The reporter said that Officer McGurk, who made the arrest, was a defective on the police force. He should have said that Officer McGurk was a detective on the police farce."

Here is an interesting fact. 526 grams of borax decahydrate will dissolve in a liter of glycerol. I dissolved 120 grams in 500 ml, added 10 grams each of Phenidone and ascorbic acid, used 1+50 dilution of this solution to develop Arista Premium 400 for 16 minutes at 70F with excellent results. I think this might be a good stand developer. The pH of the working solution was about 8.5. The borax brings with it the water of crystallization, but at most that would amount to about 56 grams of water. If you have time for such frivolities, it's fun to play with. Even with heat it seems it will not all dissolve, but give it some time.

I was reading through a thread on Photo.net from 2004 dealing with accelerants for Gainer's developers. At the time, I had little interest in borax, but used carbonate or TEA. It turns out that the high solubility of borax in glycol is accompanied by formation of boronate esters that will be completely useless as bases. This is most likely to happen when heat is used to hasten solution. It explains why I thought my pH meter had gone bonkers. A working solution did a pretty good job of stand development at 45 minutes, 70 F.

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.

And presumably glycerol doesn't affect the buffering ability of borax like glycol?
At 1:50 my scratchings on an envelope indicate there's 5g Borax - 0.4g Phenidone - 0.4g AA per litre (working). My maths has been known to err in the past but is there a decimal place wrong in there?
Long ago I made up some PC-glycerol and it appears to keep just fine. I had no glycol.
Murray

Quote:

---

Originally Posted by Alan Johnson

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.

---

The pH of this working solution is considerably lower than that of the PC-TEA working solution. I added more Phenidone so I wouldn't have to wait so long. That is what prompted me to try stand development. 45 minutes was in fact somewhat too long, as there is some washing out of the highlight in the "mane" of my great grand daughter's hobby horse. You'll see it if I can get the photo transmitted.