You are looking in the wrong places. You want developer stabilizers, not silver halide solvents! At least in this context. As for silver halide solvents, you just have to experiment as the level is very much a function of the developer formulation itself. This is grinding plodding work that involves the use of what is called a factorial experiment.
I would have to look this up and perhaps it is in Haist, but some amino acids will severely reticulate film. Be very careful when you try to use them in tests as you may damage your film. I remember doing so many years ago! Sorry I cannot remember which one(s) do so.
If Mark is the same Mark Overton who used to post on Usenet, he actually does know how to fly, and spin.Mark...... The problem is that you are trying to fly before you can walk and that will take a bit of time. As Alan says, this is advanced stuff!
PE
That's no problem. I'll just name the developer "Reticulon".
Seriously, you are right about learning to walk first. I've realized that my knowledge of chemistry is badly rusty after decades of disuse, and that I need to buy a good college freshman level book and read-up.
Alan: Regarding diethanolamine bisulfite, that's a compound of DEA? DEA itself is a solvent, although in another posting, PE indirectly says it's probably a bit weaker than sulfite. Would the bisulfite-version be a stronger solvent?
Gerry: Thanks for the suggestions, and I'll look at the health food store for those amino acids, especially cysteine. Would any cysteine-compound suffice, or must it be cysteine-HCl?
Here's a formula that I'm thinking of mixing up and using as a basis of experimentation:
Makes 1 litre of working solution. The intention is that the metaborate would react with the ascorbic acid in situ, creating the 12g of ascorbate specified in the XTOL-patent. Other byproducts concern me, especially H2O. The remaining metaborate would be the alkali and form a buffer with the boric acid. The boric and/or metaborate would be adjusted to give a pH of 8.2, making this similar to XTOL but with no halide-solvent. And then would come the fun part of trying halide-solvents and probably tweaking other things. As always, comments about all this are welcome.
Propylene glycol .............. 48 ml (adjust so result is 50 ml. or 100 ml if too viscous)
Ascorbic acid ................. 10.7 g (alternate: Sodium ascorbate 12g)
Sodium metaborate ......... >=8 g (4g to convert ascorbic, + 4g for XTOL)
Boric acid ...................... ?? g
Phenidone ..................... 0.15 g
Mark Overton
Mark
Remember the rule that like dissolves like, sodium metaborate is an inorganic salt and would not dissolve in a glycol to any extent. The boric acid would probably form a borate ester with the glycol just as glycerine does. As I mentioned you need one or more compounds such as DEA and TEA to adjust the pH.
The addition compound of DEA and sulfur dioxide in a developer like HC-110 is used to supply sulfite ions when it is dissolved in water. It is used because an inorganic sulfite like sodium sulfite will not dissolve in organc solvents.
You will need to use the amino acid cysteine and not its HCl salt. I saw it quoted on one health site for $10.15 for 100 g but have seen it even cheaper. This is all somewhat speculative but cysteine having a thiol group is in the class of compounds mentioned as silver halide solvents. How much would be needed in a developer to reduce grain would have to be arrived at by trial and error. I would suggest first mixing working strength trial developers directly in water solution to arrive at a useful combination. Only then would I work on a glycol concentrate.
Jerry
Tronds,
When heated sodium metaborate decahydrate (borax) will dissolve in its own water of crystalization. I suspect that something similar is happening with ethylene gycol in that the borax is dissolving in what is essentially a mixture of glycol and water. This points out a problem since the purpose of using glycols is to provide a waterless solution to prevent oxidation of the developing agents. Inorganic compounds with water of crystalization will defeat the concept of a water-free developer concentrate since they add water to the solution.
Thanks for mentioning this.
Jerry
I don't know how different propylene glycol is from etylene glycol, but consentrated engine coolant, etylene glycol can dissolve 12g sodium ascorbate, some phenidone, 20g borax and 4 g lye in 100ml. PC-glycol-metaborate.
Does it really matter, if its hygroscopic, and if it stores chemicals protected from the atmosphere and oxygen for a long time while being hygroscopic, does it really matter?
Tronds,
When heated sodium metaborate decahydrate (borax) will dissolve in its own water of crystalization. I suspect that something similar is happening with ethylene gycol in that the borax is dissolving in what is essentially a mixture of glycol and water. This points out a problem since the purpose of using glycols is to provide a waterless solution to prevent oxidation of the developing agents. Inorganic compounds with water of crystalization will defeat the concept of a water-free developer concentrate since they add water to the solution.
Thanks for mentioning this.
Jerry
The chemical maxim that like dissolves like is true. Borax, an inorganic salt, is insoluble in methyl alcohol, an organic solvent. Diols, where the two -OH groups are on adjacent carbons, such as the glycols presents a special case with borates in that they form borate esters. This increases the solubility. The large water of crystalization, 10H2O, also helps.
PE said inorganics should precipitate out. Could you try heating a sample of this mixture to 100C to drive out any water? Also, you can measure the volume or weight of the sample before and after heating to test whether some water was lost. I'm curious about this.
Best,
Mark Overton
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