Sodium Metaborate from Borax and Lye

[gainer]

I have been playing with concentration, but not in the conventional way. Make a solution of 9 grams ascorbic acid and 24 grams of borax in water to make a liter. Use this solution to dilute the original solution. Thus the concentration of phenidone is reduced while other ingredients remain the same. Thus far I have tried 0.8 (original), 0.4 and 0.2 grams of phenidone per liter. The time of development for FP4+ at 68 F is 8 minutes for the later one. Next I think I shall try waving a thimblefull of phenidone over the developing tank while developing in the ascorbate-borax solution. I already tried that solution without the magic act and got no measurable density.

My camera was set to bracket + and - 1/2 stop and I can see some difference in density but not in shadow detail or gradations. If I brag too much you will ignore me completely, as you should, so I must leave it to someone else to try the idea and report on it.

I know the fact the considerable dilution of the type I described has little effect on development time with agitation must put off those who use stand development. I have not tried it, but if I do it will be with a development time 1.5 times the agitated time. That time should give good results as far as average density is concerned, but I have no theory to predict the possibility of streaking or mottling that I reported in Photo Techniques some years ago when I tried it with Rodinal and Pyro.

I guarantee you will not have to divide the solution, and it will be good for at least 8 rolls per liter. That would be 8 8x10 inch films per liter, one at a time or interleaved. I hope if you try this, you will do it in such a way as not to break my bank if it fails.

 

[gainer]

My brain was not working even as well as usual. The original original had 1.6 g/l. I am now down to 0.4 g/l. I think I should go another notch down just to see what happens.

 

[dancqu]

My brain was not working even as well as usual.
The original original had 1.6 g/l. I am now down to 0.4 g/l.
I think I should go another notch down just
to see what happens.

Here's one from Patrick Dignan. In 750ml of water dissolve:
sodium ascorbate 2 grams
borax 2 grams
phenidone 0.04 grams
water to make 1.0 liter

For a phenidone concentrate he suggests 1 gram of
phenidone and 5 grams of sodium bisulfite in 1 liter of
water. I can manage just under 4 grams per liter using
his method. I wonder if it might not be better to make
the concentrate using ascorbic acid. Dan

 

[gainer]

I'll bet the pH of the late lamented Patrick Dignan's formula is about 9, and that the addition of another 10 grams or so of borax and 8 grams of sodium ascorbate would have no effect on its initial performance, but would allow it to be reused without replenishment. I'll mix up a bit and see what the pH is, so I won't have to wager.
I think the best solvent for stock solutions of phenidone is propylene glycol. Glycerine may be used, but the viscosity at room temp is high. Neither one needs a preservative, and the solution can be 5 or 10 percent.
I just did a test last night using 0.1 g phenidone per liter. It's still an 8 minute developer.

 

[dancqu]

[QUOTES=gainer;491920]
"I'll bet the pH of the late lamented Patrick Dignan's formula
is about 9, and that the addition of another 10 grams or so
of borax and 8 grams of sodium ascorbate would have no
effect on its initial performance, but would allow it to be
reused without replenishment. I'll mix up a bit and see
what the pH is, so I won't have to wager."

Likely about ph 9. He suggests the bicarbonate method for
converting the A. acid to ascorbate. His formula is of course
working strength: .04 grams phenidone/liter. The OP's pc-glycol
runs .05 grams/liter. Either good for at least two rolls. Perhaps
at .02 grams/liter a good compensating or stand developer?
One-shot is what I've in mine. Dan

"I just did a test last night using 0.1 g phenidone per liter.
It's still an 8 minute developer."

 

[gainer]

With 0.05 g/l it is still only a 9 minute developer, but it may have hit the downward slope of the activity curve. 0.025 might give what you want for 20 0r 30 minute stand development. It should have a long storage life and high development capacity if it is true that the phenidone is regenerated until the ascorbate is used up.

Be sure, if you try stand or minimal agitation, to compare the results with those from using continuous or the usual intermittent agitation, to see if the extra wait is worth it.

 

[MichaelMadio]

I need some clarification here about mixing this type of developer as a stock solution in water. It is my understanding that mixing in water leads to short shelf life and this is the reason for using formulations like PC-TEA or PC-Glycol where water is added just before use. Is it the relatively large quantity of ascorbic acid that acts as a preservative in this case (this uses ~8 g/L of AA vs PC-Glycol which uses ~2 g/L when mixed at 1:50)?

 

[dancqu]

I need some clarification here about mixing this
type of developer as a stock solution in water.

I mentioned some possible downside when mixing phenidone
with a preservative using water. Patrick Dignan helped popularize
phenidone and at his own expense had the material established
as non-hazardous. One of my previous posts mentions his
water and sodium bisulfite method and my results with it.
I've a longevity test due. He must have had some
success with that method.

But now we are covering new ground. My suggestion is to
dissolve the phenidone in an ascorbic acid solution. How about
considering the pc-glycol mix you've mentioned; ascorbic acid
10%, phenidone .25%, plus water: 1:50 with 2 tbsp of
borax per liter.

Two big question marks: how well will the phenidone dissolve
in an ascorbic acid solution at close to room temperature and
how well will it keep. As a routine matter I split a batch of what
ever into small well sealed glass Boston Round bottles. So I'd
hope for several weeks of full strength or near. Dan

 

[Maine-iac]

But now we are covering new ground. My suggestion is to
dissolve the phenidone in an ascorbic acid solution. How about
considering the pc-glycol mix you've mentioned; ascorbic acid
10%, phenidone .25%, plus water: 1:50 with 2 tbsp of
borax per liter.

What's the solution for 60 year-old brain cells and optic nerve that translated the 2 tbsp. of borax per liter into 2 tsp. and then wondered why my roll of ACROS (fortunately only a test roll) barely developed a visible image in 8 minutes?! :rolleyes:

Since borax dissolves considerably more slowly than either metaborate or carbonate, what's the real advantage of using it in the PC-Glycol formula?

Larry

 

[gainer]

I need some clarification here about mixing this type of developer as a stock solution in water. It is my understanding that mixing in water leads to short shelf life and this is the reason for using formulations like PC-TEA or PC-Glycol where water is added just before use. Is it the relatively large quantity of ascorbic acid that acts as a preservative in this case (this uses ~8 g/L of AA vs PC-Glycol which uses ~2 g/L when mixed at 1:50)?

Water itself is not the culprit. It is the oxygen dissolved in the water. It there is enough ascorbate to scavenge the oxygen and have enough left to regenerate the pheindone, the water solution will last a long time in a closed container,

While oxygen uses some ascorbaate, converting it to dehydroascorbate which has a lower pH than ascorbate, it does not produce bromides and iodides as does developing film. These compounds are restrainers, but not as much for phenidone as for other agents.

 

[gainer]

Two big question marks: how well will the phenidone dissolve in an ascorbic acid solution at close to room temperature and
how well will it keep. As a routine matter I split a batch of what
ever into small well sealed glass Boston Round bottles. So I'd
hope for several weeks of full strength or near. Dan

Two solutions: dissolve the phenidone in glycol or glycerine. Keep a separate solution of ascorbic acid - borax. This solution will scavenge oxygen at lower pH than it will develop film, IIRC. This is if you are worried about the storage life of the complete developer. But you see that if the ascorbate-borax solution scavenges oxygen and still works with the phenidone as a complete developer, why not mix the complete developer from the start?

The age of the PCB developer is not as much a factor as the number of times you open the bottle and pour out and back in. The oxygenation of the developer can also depend on the method of agitation during development. In a sealed developing tank, there can only be so much oxygen in it when it is loaded, so the more nearly full the tank, the less oxygen. I prefer a full tank and reel or reels free to move. Stand or semi-stand is another approach. In any case, the ascorbate is depleted and the pH is eventually reduced enough to have an effect, whether it is due to aerial oxidation or regeneration of the phenidone. I know for a fact that standing overnight in an open pitcher had no effect on the rate of development in half a liter of the water mix.

 

[MichaelMadio]

What's the solution for 60 year-old brain cells and optic nerve that translated the 2 tbsp. of borax per liter into 2 tsp. and then wondered why my roll of ACROS (fortunately only a test roll) barely developed a visible image in 8 minutes?! :rolleyes:

Since borax dissolves considerably more slowly than either metaborate or carbonate, what's the real advantage of using it in the PC-Glycol formula?

Larry

For me, I just don't like what I get with sodium carbonate (I think the PH is too high) and I like the results with sodium metaborate. I'm out of sodium metaborate, don't feel like buying more and was considering making my own with borax + lye. As it turns out, using just borax gives me results as good as sodium metaborate so now I don't have to go through the trouble of making/storing a home-brew sodium metaborate solution. If you have a supply of sodium metaborate it's probably better than borax as it dissolves quicker.

 

[dancqu]

What's the solution for 60 year-old brain cells and optic
nerve that translated the 2 tbsp. of borax per liter into 2 tsp.
and then wondered why my roll of ACROS (fortunately only a
test roll) barely developed a visible image in 8 minutes?!

Since borax dissolves considerably more slowly than either
metaborate or carbonate, what's the real advantage of using
it in the PC-Glycol formula? Larry

Grams and grains are another two to watch out for.

I've mentioned the combination of sodium bicarbonate and
sodium carbonate to achieve any ph twixt 8 and 11.5. That
in post 9 this thread and Mr. Gainer has some comments on
carbonates in his post 10.

For film developing I think the bicarbonate alone may suffice.
Expect longer development times; perhaps up from 8 minutes
with borax to 12. At that lower ph finer grain should result.
Apart from the film itself ph has the most affect on grain
size. How it might affect film speed I could not say.

For myself, being such a minimalist, a single chemical
approach to the correct ph has appeal. Dan

 

[gainer]

Borax, I think, is a better buffer than the carbonate-bicarbonate pair. This fact may be of little importance when 1-shot method is used, but I had in mind a developer that could be reused without replenishment and without much concern about keeping the ratio of developer to film area constant.

Borax, being a good buffer, has a narrow range of pH. The borax-boric acid pair is often used for lower pH, and the borax-hydroxide pair is used for higher. The metaborate is a pretty good buffer. In this developer I wanted to keep pH below the point where ascorbate can develop alone, following some comments by PE. I don't know if I proved anything, but I did learn a few things.

 

[grainyvision]

Reviving this ancient thread, just in case anyone was curious about an alternate form of metaborate which is very difficult to buy, but easy to synthesize. I synthesized potassium metaborate, which seems to be greatly more soluble than sodium metaborate and has otherwise identical properties for photography purposes.

Instructions to make 150ml of ~50% solution by weight (anhydrous) potassium metaborate:
* Don proper PPE, especially gloves and safety goggles!
* 70ml distilled water, preferably ice cold
* 51.3g potassium hydroxide -- add SLOWLY in small batches using an cold water or ice bath as needed. If it is too hot to handle, do not add more hydroxide. Do not breathe any steam from this!
* 56.6g boric acid -- Add about 10g at a time. This will cause the solution to heat up some
* There should now be about 130ml of solution. Add more water to make about 145ml
* This calculates for a slight surplus of boric acid, which will not dissolve or will form (also insoluble) the potassium version of borax, potassium tetraborate. There should be a bit of fluffy white clumps that sink to the bottom. Add very small amounts, like 0.3g at a time of potassium hydroxide to dissolve close to all of it. Get to where there is only a tiny amount of the fluffy white clumps left. If you overshoot it, add a small amount more boric acid.
* Top solution to 150ml with distilled water
* Filter the solution through a coffee filter. Testing pH using test strips should reveal a pH of around 12
* The solution will be a slight yellow-orange and be very "slippery" feeling with gloves. Unsure if that is an impurity on my part or just what concentrated potassium metaborate solution looks and feels like.

I expect that the concentration could be increased beyond 50%, but I can not find any solubility data for potassium metaborate, so 50% seemed like a round enough amount to aim for.

pH tests of the solution using pH test strips:
* 1ml of solution + 10ml water gives pH of 11.5
* 1ml of solution + 110ml water gives a pH of 10

Usage of the solution:
* 1g of sodium metaborate tetrahydrate (most common form) is equivalent to 0.6g potassium metaborate anhydrous or 1.2ml of the 50% solution above.
* 10ml of 25% sodium metaborate tetrahydrate solution (the solution proposed in this thread) contains 2.5g of sodium metaborate tetrahydrate, equivalent to 1.5g of potassium metaborate anhydrous or 3ml of 50% solution.

The difference in solubility and convenience for highly concentrated developers of using the potassium salt should be readily apparent, and there are potential benefits to potassium salts in terms of film speed with developer formulations.

This is a greatly convenient form of metaborate, considering that sodium metaborate can be quite stubborn to dissolve if very much needed. I may try to dry it as well because I suspect it may be more easily soluble in glycol than sodium metaborate, but potassium metaborate is a chemical I can hardly find any info about, so I'm unsure what it's most natural hydration state would be or even if it is soluble in glycol. I only know that it greatly exceeds the solubility limits of sodium metaborate, similar to how almost all potassium salts compare to sodium

 

[Raghu Kuvempunagar]

There was a recent post by @Nikola Dulgiarov which gave a simple method for the synthesis of Sodium Metaborate from Borax and Sodium Hydroxide. The goal was to synthesise Sodium Metaborate in crystal form, not aqueous. I wonder a similar method might be useful for Potassium Metaborate though you would have to use Boric Acid instead of Borax.

 

[grainyvision]

There was a recent post by @Nikola Dulgiarov which gave a simple method for the synthesis of Sodium Metaborate from Borax and Sodium Hydroxide. The goal was to synthesise Sodium Metaborate in crystal form, not aqueous. I wonder a similar method might be useful for Potassium Metaborate though you would have to use Boric Acid instead of Borax.

In theory the method listed would work with adaptation. Btw the thread is here: https://www.photrio.com/forum/threads/kodak-sodium-metaborate.186175

My concern is that if potassium metaborate's preferred hydration state is anhydrous, then extra water will be produced from the reaction.. and it could be similar to potassium sulfite in that getting an anhydrous product may be excessively difficult, due to ability to wick moisture from the air. The biggest issue is just safety though. There's a reason the rule "never add water to hydroxide" is a thing. I wouldn't feel comfortable doing a reaction like that without the really long rubber glove PPE (think for handling strong acids), and various other bits of PPE. The issue is that the reaction can not be made more safe by slowing it down. Instead the only way to slow it down is with reducing batch size. The amount of PPE required to have a comfortable margin of safety exceeds the cost of simply buying a vacuum desiccator. Running the same procedure using potassium hydroxide and boric acid is even more dangerous because of the much larger amount of hydroxide required and hydroxide + boric acid being more vigorous. You could potentially "split" the reaction into boric acid -> tetraborate -> metaborate, but I think given the high concentration, it is easier and much safer to just use the 50% solution.

 

[Raghu Kuvempunagar]

How're you storing your 50% solution?

 

[grainyvision]

How're you storing your 50% solution?

Chemical grade plastic bottle. Glass would likely be better but didn't bother.

 

[Rudeofus]

There is solubility data for Potassium Borax here, and while it is less soluble than Potassium Metaborate, it is still quite soluble at room temperature (15.8% w/w). At pH 12 I would, however, not expect much Potassium Borax to be present in your solution.

 

[grainyvision]

That's my thoughts. I assume if there is any borax left, it's insignificant enough for development purposes

 

[Rudeofus]

Measuring this extremely concentrated solution will most likely not show a useful pH due to ionic strength. I recommend you dilute a small sample down to 1%, that's where you can see, whether you have:

1. A mix of Potassium Metaborate plus Potassium Tetraborate
2. mostly Potassium Metaborate
3. A mix of Potassium Metaborate plos Potassium Hydroxide

In this figure list there is Figure 9 and Figure 10, which both suggest a pH of 12 for close to 100% metaborate ion. I would not go beyond pH 12 or you will have version 3 of the above list. There is also this patent, which strongly suggests, that a Potassium Metaborate solution starts at pH above 11.