Borax/S.hydroxide vs. S.bicarbonate/S.hydroxide

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steelneck

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Pros and cons about using a mix of Borax/S.hydroxide vs. S.bicarbonate/S.hydroxide together with stock solution of PC-glycol. What effect on grain will they have? If it is made as stock "part B" solution in water, which of them can be expected to have longest shelf life? Can borax or those salts be mixed in glycol too? Would there be a point of that?
 

Alan Johnson

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Borax alone will work and give the finest grain,see post 24:
www.apug.org/forums/forum37/40430-sodium-metaborate-borax-lye-3.html
The approximate pH of 10 g/L solutions is:
Borax-9.2, Sodium Metaborate-11.0, Sodium Carbonate-11.4,
Sodium Hydroxide-13.1
Increasing the pH using mixtures will reduce the development time but increase grain.
None of these inorganic compounds will dissolve in propylene glycol.In water the borax,metaborate and carbonate solutions are stable but the bicarbonate and hydroxide may slowly convert to the carbonate in air.
 

Photo Engineer

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At equivalent pH and equivalent buffer capacity, both Borax and Carbonate are about equivalent.

Borax is more toxic in effluent than Carbonate.

Carbonate generates gas when used with a stop bath and could cause problems with some poorly hardened films and papers.

PE
 

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Well the Borate would buffer between 9.5 - 10.2 under best conditions and the Carbonate between 10.0 and 10.5 when mixed with the hydroxide. TSP buffers best in a range of about 11 - 12.

PE
 
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steelneck

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So, borax alone mixed in water as stock B part? No sodium hydroxide.

What i am after is a two part stock solution that lasts for years, and is easy to mix by volume and dilute in water just when i need it.
 

Photo Engineer

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Here lies the problem.

Most everyone who is not a chemist, specifies a developer by the mix of ingredients, but the pH of each part should be known so that they can be mixed up to a constant potency. Without pH, it is hard to specify or even calculate where you want to be. You, nor anyone else, says. All Kodak formulas are made up to a specific pH value.

PE
 

Photo Engineer

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Murray;

That is the problem as well. Kodak only gives the pH for some formulas, not all. For example, all color formulas have a pH specified. However, if you look carefully at some B&W developers they will tell you in the section on replenishment. Kodak did this because pH meters were phenomenally expensive way back when, and difficult to use. They too simplified things by giving an exact formulation that would give the desired pH value, but this did a disservice in that most photographers assumed pH was not needed.

Kodak also assumed that big production labs doing replenishment would have a meter and so the replenishmnet data on some developers included pH data.

However, for a reformulation such as posed in the OP, this becomes a problem.

I assure you though that pH is a critical QC item on all Kodak products. I have applied that thinking to all of my own personal formulation. The pH of all of my formulas is known and is down on paper for use. See the Super Fix posted here for an example. However, in this case, I have no idea what the target is, so I cannot give ratios or concentrations.

PE
 

Alan Johnson

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So, borax alone mixed in water as stock B part? No sodium hydroxide.

What i am after is a two part stock solution that lasts for years, and is easy to mix by volume and dilute in water just when i need it.

Maybe you would be the pioneering investigator of this,nobody published details or film development times.
PC-TEA and PC-Glycol have nearly identical amounts P&C and the pH of 1:50 PC-TEA is about 9.If enough borax is put in the 1:50 PC-Glycol to make the pH about 9 (It's then called PC Borax),assuming this is possible, one would guess,huh,it would behave like PC-TEA 1:50.
If that works,use the same development time as PC-TEA,ie the time for Xtol 1+2. www.digitaltruth.com/devchart.php?doc=discontinued
Some pH paper would probably be adequate for this.
 
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steelneck

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How much borax is it possible to solve in water? I read somewhere that it will be saturated around 24g/L. If that is true, then it would not be much of of a stock solution "part B". How much borax could glycerine "swallow"? But i suspect that will be a sticky syrup.
 

Murray Kelly

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Your figure for the solubility of borax cas 1330 43 4 seems about right.
Glycerol solutions of borax release boric acid which lowers the pH, dont go there,see post 59:
www.apug.org/forums/forum216/62155-borax-project-6.html

In that thread Pat Gainer found that the pH had fallen to 8.8 IIRC. This may be what someone needs for even slower or finer grain. It equates to a 'Buffered Borax' - an unopened jar of which I picked up at a meet. It bears the brand Kodak.
At pH 8.8 one is at or v.v. close to Technidol working solution pH and I have been left wondering if that is indeed what Kodak used to set the pH of that developer.
So, borax and a saccharide (glycerol) may be exactly what someone wants as a pH setter. I am having terrible trouble buying boric acid and even tho I assure the pharmacists I don't want to make bombs I still can't wheedle any off them. Borax/glycerol may be my answer?
Murray
 
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