Thank you for noticing the error in the formula I posted. The amount of TEA in the formula should be 120 ml, not 12. The Photographers' Formulary formula is slightly different. As posted on their website, it is:
Metol 17.8 g
Oxalic Acid 1.7 g
Potassium Metabisulfite 4.3 g
Sodium Sulfite 140.0 g
Pyrogallic Acid (Pyro) 51.2 g
Triethanolamine 133 ml
Water to 4 liters
OK one more question : (I guess it is too late for you to go back and edit the formula, false formulas on the net is annoying, it was dangerous, when I was discussing reloading ammunition and someone posted wrong type of powder...)
But these two formulas, the3 last and the revised first : will all the ingredients dissolve on the TEA, and will this be like a sticky goo, referred to elsewhere? This should store *forever* in a closed bottle, most likely?
Pyro-triethanolamine film developer
Oxalic acid 1.5 g
Potassium metabisulfite 3.9 g
Pyrogallol 46 g
Metol 16 g
Sodium sulfite 116 g
Triethanloamine 120 ml
Water to make 4000 ml
Dilute 1:1 for use.
Develop Tri-X 5-1/2 minutes
Triethanolamine is an alkali accelerator:
It will not,in absence of water, dissolve the ionic sulfur groups in metol,metabisulfite or sulfite.
Oxalic acid has been tried to coat powders to improve their stability,IDK if that is its purpose here.
TEA is a fair bit more liquid when warmed. I set it in a bowl of hot water to pour in the winter here; it 'freezes' solid below 20C I think I recall.
1. Since the two formulas presented here are in different order, what is the correct sequence for what gets added when?
2. NWorth's version looks essentially a tiny bit more concentrated than Erik's. The ratios are not constant, but the general drift is that they should act much the same. Are they from a common "ancestor" formula?
I think that all formulas in this thread maybe incorrect. I found next formula for this developer here
Metol 17.8 grams
Oxalic Acid 1.7 grams
Potassium Metabisulfite 4.3 grams
Sodium Sulfite 140.0 grams
Pyro 51.2 grams
Triethanolamine 133 ml
Water to make 2 gallons
2 gallons = 7.57l, so we can calculate amount for 1l
Metol 2.4 grams
Oxalic Acid 0.23 grams
Potassium Metabisulfite 0.6 grams
Sodium Sulfite 19 grams
Pyro 6.8 grams
Triethanolamine 18 ml
Water to make 1l
still don't understand why we need Oxalic Acid in formula. pH buffer?
You are correct this is NOT a staining developer.
Originally Posted by juan
The TEA raises the pH of the solution to allow the developinjg agents to work. It also acts as a mild silver halide solvent to provide finer grain. Agfa made Studional (Rodinal Special) which was also based on TEA. This was a good developer which never really caught on in the US.