Concentrated D-76, How do I go about making it?

[gainer]

Would Scalpicin (TM) work? It is salycilic acid solution. Maybe more expensive in the long run, but quicker to get for a trial?

 

[Tom Hoskinson]

Oh bugger, didn't realise that it doesn't keep well, I already had the 4x concentrate mixed up and ready to go by the time I read you posts.

Hamster, Pat Gainer gave you two developer recipes - I think this may have confused you.

Gainer Recipe #1:
1 liter water.
1 tsp washing soda. (5 grams)
1/2 tsp ascorbic acid powder. (2 grams}
1/8 tsp metol. (0.25 grams)
1 teaspoon = 5 ml. I don't know if that is standard everywhere.
Use it as D-76. For example, HP5+ for 8 minutes at 21 C.

It mixes quickly and should be cheap even if you use high quality chemicals. It is more consistent than you might expect. Make it stronger to use with paper.

This developer uses sodium carbonate (washing soda) as the alkali and it will have a short shelf life. Adding triethanolamine to this recipe will not help its shelf life.

Gainer Recipe #2:

"Concentrated solutions in water do not keep very long, especially if you include the carbonate. If you can find triethanolamine TEA for short), 100 grams of ascorbic acid and 2.5 grams of phenidone will dissolve in hot TEA to make a liter of stock solution. First mix the ascorbic acid with about 100 ml of very hot water. Add the hot TEA to that mixture and then the phenidone. It takes a while to dissolve. You may dilute 1 part of this with 50 parts of water to make a working solution that you may treat as D-76. The stock will last a long time."

In Gainer Recipe #2, the triethanolamine plays several roles:

1. The triethanolamine is the solvent and also acts as the preservative. From my experience, I would expect Gainer Recipe #2 to have a shelf life in years.

When water is added to this concentrate to make a working developer solution, the working solution that results will have a short working life (hours or a few tens of hours).

2. When water is added, the combination of water and triethanolamine provides the alkali that activates this developer.

 

[gainer]

I have used it as a print developer as:
1 quart (or liter) water.
1 tablespoon sodium carbonate.
1 tablespoon ascorbic acid.
1/4 teaspoon metol.

It has lasted through a several hour session, and I have used it the next day upon occasion. It has an advantage of sorts over many print developers I have used. It does not turn dark and muddy until the end. You are right, I would not store it in a bottle and expect it to work well a few days later, but you may be surprised at its tray life.

 

[dancqu]

I have used it as a print developer as:
1 quart (or liter) water.
1 tablespoon sodium carbonate.
1 tablespoon ascorbic acid.
1/4 teaspoon metol.

Interesting formula. I and I'd expect the OP would like
to see those amounts in grams. You do post in gram
amounts now and then. Chop Sticks and Soup
Spoons in China.
At first glance the ascorbic acid is no more than a sulfite
substitute in an Ansco 120.
On second glance it is a metol regenerated developer.
If I've got my facts straight an ascorbate will while a
sulfite will not, regenerate metol. Dan

 

[gainer]

I'm not sure the regenerative theory of superadditivity is all there is to it. I prefer to think of the metol or phenidone as a catalyst for the ascorbic acid, hydroquinone or whatever. Be that as it may, the result is, like a catalyized reaction, that the ascorbic acid does the work and is used up while the metol is not changed until the ascorbic acid is used up. In any case, metol is superadditive with ascorbic acid whether sulfite is present or not. If you provide more ascorbic acid than the amount for maximum synergism, the tray life will be longer. Of course, the pH must be kept up.

Measurements by volume are quite sufficiently accurate for a print developer and are much more convenient. The most accurate possible measurements are no longer accurate after the first print or two. Also, if you are concerned about consistent measurements, you can weigh the tea and tablespoon amounts once and use the same weights the next time. Or, you can try different weights and see if it makes any difference. When I first started using volumetric measurements in 1973, I experimented with Kitchen Tested D-76 and varied the amounts of critical ingredients by 1/4 teaspoon in a sort of ring-around set. There was remarkably little difference. These results were published in Petersen's Photographic in April, 1973, before a group called, I think, Zone V began selling chemicals, measuring spoons and formulas.

Anyway, if you were to use 15 grams of sodium carbonate, 12 grams of ascorbic acid and 1 gram of metol you would not be disappointed.

 

[gainer]

By the way, the standard teaspoon is 5 ml, the standard tablespoon 15 ml.

 

[Gerald Koch]

I was able to get salicylic acid through a drugstore chain. I think it was around $13 including tax for 100 g USP. It took 2 days because they had to get it from their warehouse.