The why
I have been experimenting lately with phenidone / vitamin C developers. E-72 for paper and PC-TEA for film. Both have a very similar compostion, just the solvent is different. In both cases I had failures, so I'd like to share some experience which might help someone walk the same path. To success. Not failure.
The main problem is shallow blacks and lack of contrast. Basically a lack of activity of the developer. In my experience, the culprits are in decreasing order of likelihood:
1. Too high PH = too little sodium carbonate.
2. Too little vitamine C.
3. Dead phenidone.
If you make your stock solution without the sodium carbonate - as you should to have a long shelf life - then the working solution will be too acidic to even start working.
The howto
1) Make the working solution. 1 : 3 with standard stock or 1 : 9 with tripple strength stock. Start by adding sodium carbonate to your working solution. This applies only to E-72. PC-TEA does not use carbonate. Start with 2.5 tablespoons (38 g) per litre of working solution. That should be just about right. If you can measure PH it should be around 11. Put a test paper strip in. If the blacks are not satisfying, take out 100 ml of your working solution for further testing. Add carbonate in 1 gram increments. Test until there is no change. If the blacks are still not ink deep, it could be the phenidone / vitamin C ratio.
2) The ratio of phenidone to vitamin C should be about 1 : 50 in weight. The ratio of vitamin C to carbonate should be about 1 : 4 in weight. Either too little or too much vitamin C can make the developer inactive. Too little is the more likely case, as the vitamin C oxidizes and gets used up. Too much is unlikely, as vitamin C is shelf stable and you weight it out in the stock solution. Unless you phenidone is dead. To test, take 100 of your working solution which already has the carbonate added (PH is 11). Start adding 1 g of vitamin C and 4 g of carbonate. If things improve, then you had too little active vitamin C in the solution. If the blacks are still greys... Then it is time to look at the phenidone.
3) Phenidone is quite stable on the shelf, but it can degrade if exposed to air and heat. To keep the phenidone active almost indefinitely, make a 2% solution in glycol. See the recipies below. If nothing of the above helps to bring the developer to live, definitely try a fresh batch of phenidone.
The disclaimer
I am no darkroom chemistry expert. But I did do my best to verify all stated amounts. And present what seems a sensible approach, given my level of knowledge. May someone notice an error, gladly correct me. And... I did manage to make said developers produce super deep blacks. Do not give up on them. They are great stuff.
The recipies
2% PHENIDONE SOLUTION
2 g of phenidone dissolved in 98 ml of propylene glycol heated to 60 degrees C. Do not heat over 70 C.
E-72 PAPER DEVELOPER - Stock
Water (50°C) : 750 ml - fill to 1000 ml after dissolving chemicals
Sodium sulfite (anhydrous) : 45 g - 2 tablespoons
Phenidone : 0.3 g - 15 ml 2% solution
Ascorbic Acid (Vitamin C) : 19 g - 4.25 teaspoons
Potassium bromide : 2 g - 1 quarter teaspoon
(Optional) Pyrogallol : 5 g to 20 g - 1 to 4 teaspoons
Mix from 1 : 1 to 1 : 3 with H2O
Add to the tray shortly before use:
Sodium carbonate : 80 g (5 tablespoons) per 1 litre of stock solution - DIVIDE by the number of litres in your working solution.
E-72 PAPER DEVELOPER - Triple Strength (recommended)
Water (50°C) : 750 ml - fill to 1000 ml after dissolving chemicals
Sodium sulfite (anhydrous) : 135 g - 6 tablespoons
Phenidone : 0.9 g - 45 ml 2% solution
Ascorbic Acid (Vitamin C) : 57 g - 13 teaspoons
Potassium bromide : 6 g - 3/4 quarter teaspoon
(Optional) Pyrogallol : 15 g to 60 g - 3 to 12 teaspoons
Mix from 1 : 3 to 1 : 9 with H2O
Add to the tray shortly before use:
Sodium carbonate : 240 g (15 tablespoons) per 1 litre of triple strength stock solution - DIVIDE by the number of litres in your working solution.
PC-TEA FILM DEVELOPER
Triethanolamine : 75 ml - fill to 100 ml after dissolving chemicals
Ascorbic Acid (Vitamin C) : 9 g
Phenidone : 0.25 g
Potassium Bromide : 0.2 g
Mix 1:50 with H2O (dev times for D-76 / PC-TEA)
Postscriptum
Notice the optional pyrogallol. If nothing else helps and you have some laying around, add it. It will make the shadows go pitch black on the double. You might also like the effect it has on the tone, grain and accutance. The effect will vary with the concentration you choose. Most seem to advice about 10 g in one litre of working solution. But it will not be the original recipe any more. Pyrogallol, unlike the other ingredients, has significant toxicity. If you use it, wear gloves and use tongs. Which you should do anyway.
I have been experimenting lately with phenidone / vitamin C developers. E-72 for paper and PC-TEA for film. Both have a very similar compostion, just the solvent is different. In both cases I had failures, so I'd like to share some experience which might help someone walk the same path. To success. Not failure.
The main problem is shallow blacks and lack of contrast. Basically a lack of activity of the developer. In my experience, the culprits are in decreasing order of likelihood:
1. Too high PH = too little sodium carbonate.
2. Too little vitamine C.
3. Dead phenidone.
If you make your stock solution without the sodium carbonate - as you should to have a long shelf life - then the working solution will be too acidic to even start working.
The howto
1) Make the working solution. 1 : 3 with standard stock or 1 : 9 with tripple strength stock. Start by adding sodium carbonate to your working solution. This applies only to E-72. PC-TEA does not use carbonate. Start with 2.5 tablespoons (38 g) per litre of working solution. That should be just about right. If you can measure PH it should be around 11. Put a test paper strip in. If the blacks are not satisfying, take out 100 ml of your working solution for further testing. Add carbonate in 1 gram increments. Test until there is no change. If the blacks are still not ink deep, it could be the phenidone / vitamin C ratio.
2) The ratio of phenidone to vitamin C should be about 1 : 50 in weight. The ratio of vitamin C to carbonate should be about 1 : 4 in weight. Either too little or too much vitamin C can make the developer inactive. Too little is the more likely case, as the vitamin C oxidizes and gets used up. Too much is unlikely, as vitamin C is shelf stable and you weight it out in the stock solution. Unless you phenidone is dead. To test, take 100 of your working solution which already has the carbonate added (PH is 11). Start adding 1 g of vitamin C and 4 g of carbonate. If things improve, then you had too little active vitamin C in the solution. If the blacks are still greys... Then it is time to look at the phenidone.
3) Phenidone is quite stable on the shelf, but it can degrade if exposed to air and heat. To keep the phenidone active almost indefinitely, make a 2% solution in glycol. See the recipies below. If nothing of the above helps to bring the developer to live, definitely try a fresh batch of phenidone.
The disclaimer
I am no darkroom chemistry expert. But I did do my best to verify all stated amounts. And present what seems a sensible approach, given my level of knowledge. May someone notice an error, gladly correct me. And... I did manage to make said developers produce super deep blacks. Do not give up on them. They are great stuff.
The recipies
2% PHENIDONE SOLUTION
2 g of phenidone dissolved in 98 ml of propylene glycol heated to 60 degrees C. Do not heat over 70 C.
E-72 PAPER DEVELOPER - Stock
Water (50°C) : 750 ml - fill to 1000 ml after dissolving chemicals
Sodium sulfite (anhydrous) : 45 g - 2 tablespoons
Phenidone : 0.3 g - 15 ml 2% solution
Ascorbic Acid (Vitamin C) : 19 g - 4.25 teaspoons
Potassium bromide : 2 g - 1 quarter teaspoon
(Optional) Pyrogallol : 5 g to 20 g - 1 to 4 teaspoons
Mix from 1 : 1 to 1 : 3 with H2O
Add to the tray shortly before use:
Sodium carbonate : 80 g (5 tablespoons) per 1 litre of stock solution - DIVIDE by the number of litres in your working solution.
E-72 PAPER DEVELOPER - Triple Strength (recommended)
Water (50°C) : 750 ml - fill to 1000 ml after dissolving chemicals
Sodium sulfite (anhydrous) : 135 g - 6 tablespoons
Phenidone : 0.9 g - 45 ml 2% solution
Ascorbic Acid (Vitamin C) : 57 g - 13 teaspoons
Potassium bromide : 6 g - 3/4 quarter teaspoon
(Optional) Pyrogallol : 15 g to 60 g - 3 to 12 teaspoons
Mix from 1 : 3 to 1 : 9 with H2O
Add to the tray shortly before use:
Sodium carbonate : 240 g (15 tablespoons) per 1 litre of triple strength stock solution - DIVIDE by the number of litres in your working solution.
PC-TEA FILM DEVELOPER
Triethanolamine : 75 ml - fill to 100 ml after dissolving chemicals
Ascorbic Acid (Vitamin C) : 9 g
Phenidone : 0.25 g
Potassium Bromide : 0.2 g
Mix 1:50 with H2O (dev times for D-76 / PC-TEA)
Postscriptum
Notice the optional pyrogallol. If nothing else helps and you have some laying around, add it. It will make the shadows go pitch black on the double. You might also like the effect it has on the tone, grain and accutance. The effect will vary with the concentration you choose. Most seem to advice about 10 g in one litre of working solution. But it will not be the original recipe any more. Pyrogallol, unlike the other ingredients, has significant toxicity. If you use it, wear gloves and use tongs. Which you should do anyway.
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