Thank you all for your kindness.
Pat your indication for chemical products store is really appreciated, but I live in Verona - Italy.
If someone would be so gently to send me via email the Pat Gainer's developers formulas they will be really appreciate. Photo Techniques is not well distributed here. Thanks
Just one more comment.
Originally Posted by jdef
I think that a really interesting direction for development of either Cat-P-TEA or Pyrocat-HD would be to add a little ascorbic acid to the mix. I experimented with this briefly about 5-6 years ago with Pyrocat-HD and found that the ascorbic acid is very superadditive, maybe I should say super/superadditive, with pyrocatechin and phenidone. Unfortunatley I have lost my notes from the experiments but as best I recall the addition of ascorbic acid in approximately the same amount as phenidone in the Pyrocat-HD formula made the developer much, much more energetic than with just the pyrocatechin and phenidone. The addition of ascorbic acid also reduced the stain slightly, which made me abandon the tests at the time. However, I think there is a lot of potential with the combination of pyrocatechin/phenidone/ascorbic acid for a super elegant developer, fine grain from the stain, very high definition because of the low quantitiy of reducer, but also very, very energetic.
And oh yes, B+f was also very low with the combination.
My feeling is that anyone interested could pursue the experiments with either Cat-P-TEA or with Pyrocat-HD, with the stock solution in either water or glycol.
Last edited by sanking; 08-07-2004 at 11:01 PM. Click to view previous post history.
A bunch of things to talk about.
Yes, phenidone and pyrogallol are superadditive, and like catechol and hydroquinone it needs a pinch of sulfite to achieve that synergism. It would take more sulfite to prevent formation of stain than to activate the synergism (this is a shorter word than "superadditivity"), so it should be safe to try. I estimate the hydroquinone and catechol need a little more than equal weight of sulfite in the working solution to get full synergism.
I found a strange thing when I added ascorbate to HC110. It is a PQ developer and from my experiments adding more Q had no appreciable effect on activity. It responded vigorously however to addition of ascorbate. The PA combination needs no sulfite to activate it, but I was surprised that the P had not been "used up" by the Q. When you use catechol as a non-staining developer, it behaves pretty much like hydroquinone, so adding ascorbate or erythorbate to Pyrocat HD would probably give a boost in activity, but I wouldn't guarantee that the stain will be likewise boosted. You might have to cut developing time to keep the silver image under control, but I have a feeling the stain would still be only proportional to that part of the silver image formed by the cat.
Yes, hydroquinone will produce a stain when substituted for catechol in the Pyrocat HD formula, but it is a different color, which you may or may not like. It does make a good bleach-and-redevelop intensifier. All you need for the redeveloper is some hydroquinone and carbonate in water. Development is to completion, so H&D curve is of no consequence in that application. The dye image provides the intensification.
I will dig up my manuscript and excerpt the pertinent parts for you. It won't take too long.
Originally Posted by ongarine
Developers in organic solvents.
I found an auto supply store that had the safe propylene glycol antifreeze. It worked as well as the ethylene. Another benign solvent that works is glycerol (glycerine at the drug store), but it is very viscous, even more so than HC110 syrup.
Technical grade propylene glycol is readily available. It works, so I am sure that the additives in the antifreeze that make it green had no appreciable good or bad effect.
There are other activator solutions that you might use with A1:
1. Try 100 grams of sulfite and 2 grams of borax per liter as the "B" solution. Add 20 ml of the "A1" solution per liter just before use. This is a kind of extended life split-stock developer of the type of Paul Lewis' Mytol.
2. Use 5 grams of borax + 5 grams of sodium carbonate + 20 ml of "A1" per liter of working solution (no sulfite). Development time will be about 8 minutes at 70o F. One teaspoon each of borax and carbonate will be accurate enough due to the buffering action of the combination.
Other uses for propylene glycol.
Use propylene glycol in place of water to make the "A" solution of Pyrocat-HD. Leave out bisulfite and bromide. Heat to hasten dissolving and to drive off water. Let's call it "A2". Use the standard Pyrocat-HD "B" solution.
See http://unblinkingeye.com/Articles/PC-HD/pc-hd.html for the standard formula and developing times for Pyrocat HD.
Alternatively, use hydroquinone in place of catechol in A2. I'll bet you didn't know that hydroquinone can be a staining developer. Hydroquinone is 1,4-dihydroxybenzene. Pyrocatechol is 1,2-dihydroxybenzene. According to theory, any developer with two or more active hydroxyl groups will be an active tanning and staining developer.
Dilute 1:1:50. Add "B" to working solution just before developing. Don't be put off by the immediate change in color. Develop 7 or 8 minutes at 70o F.
If you keep phenidone in alcohol solution, use propylene glycol instead of the alcohol. Rumors that there is no way to keep phenidone in solution are greatly exaggerated. Heat the glycol or you will have to wait a week or so for the phenidone to dissolve.
Dire and not-so-dire warnings.
If you repeat my experiments but do not have a microwave oven, put the glycol in a Pyrex pitcher, set that in a baking dish in an ordinary oven. Set the oven at 250o F.. A candy thermometer is a good investment. Check the temperature of the liquid now and then, but not with your finger. If you see steam rising from the glycol it is most likely water vapor.
Propylene glycol (1,2-propanediol) and glycerine (1,2,3-propanetriol) are non-toxic to the extent that they can be used in foods, medicines and cosmetics. Propylene glycol is poisonous to cats but not to dogs. I don't think cats will ingest it willingly. Ethylene glycol is bad stuff for everyone. Dogs and little children love it because it is sweet, but it kills them. If you use it, do so with caution. HC110 contains it and diethylene glycol as well, and many of us use HC110 without a lot of worry. Maybe we don't worry enough. If you are careful, you will not have to worry.
Single solution developers
It is possible to prepare single solution developers with excellent storage life by using an organic base as solvent and activator. The organic bases become alkaline in the presence of water. Triethanolamine (TEA for short) is an example, and it is readily obtainable without hazmat shipping charges. One problem you may have is that it freezes at about 70o F. If your darkroom is colder than that you will have the strange experience of having to thaw out iced TEA before you can pour it. The freezing point will be lowered somewhat after you dissolve the solids in it. Here are some useful formulas.
Call it whatever you want. It is a phenidone-ascorbic acid developer with TEA as activator and solvent. I can't find the grain in properly exposed HP5+ or 400TMY at less than 20 power enlargement.
You may scale up the formula to any desired amount.
100 ml of TEA
9 grams l-ascorbic acid powder (Vitamin C Powder)
0.25 grams phenidone (1/8 tsp will be close enough.)
Heat the TEA to 250o F before adding the other ingredients. It won't boil, but some steam may be given off if there is any water in the solvent mixture. Steam will be evolved when the powdered ingredients are added, which I presume to be from water produced in a reaction between the ascorbic acid and part of the TEA.
Dilute 1+50 to develop 400TMax in 9.5 minutes at 70o F.
The name does not refer to its appearance or its bouquet. I heard it in a British sit-com and just couldn't resist using it. This developer contains catechol and phenidone. It is a staining developer.
100 ml TEA
0.2 gram phenidone
10 grams catechol
You may use a like amount of hydroquinone in place of the catechol if you like to save money. Call that Q-P-TEA.
Heat as before. Dilute 1+50 for use. The negatives will be lower in contrast to the eye than to the printing paper, and lower in contrast to VC than to graded paper.
If you use a 1% sodium sulfite solution (10 gram/liter) to dilute the stock you will have a fine-grain non-staining developer. You can experiment with different proportions of stock, sulfite solution and water.
This name also does not refer to its appearance but to the fact that pyrogallol is the sole developing agent. This and D-23 are the simplest single solution developers I know of. It is the only single stock concentrate that I know of with only two ingredients.
Many fear pyrogallol. That is a healthy fear, but with reasonable care there is no need to inhale or handle the pyro while mixing or using this developer.
100 ml TEA
7 grams pyrogallol
Dilute 1 + 50 for use.
Again, the negatives will be stained. This developer will produce a strong dye image on 400TMY film. It will prove to you that Pyrogallol alone is not intrinsically a coarse-grain developer.
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Thanks a lot Pat,
Photo Techniques isn't readily available in Holland either. So, I very much appreciate you publishing this here.
Pat you have all my gratitude. The manuscript you published is what, many of us, needed. Thanks also for the comments of others users.
Don't talk about this too loudly in uneducated circles, the name brings up unsavory and quite smelly visions....
Originally Posted by Tom Hoskinson
Originally Posted by Tom Hoskinson
Just one comment. I have not tested the CAT-P-TEA formula but I suspect that at the 1:50 dilution, which would be an approximate equal of regular Pyrocat 1:1:100, developing times would be quite a bit longer with CAT-P-TEA. My thinking on this is that the formula with Triethanolamine will give a a developer with a working pH of about 9.5, much lower than the PH of 10.9 achieved with the Pyrocat-HD formula. Since the threshold of developer activity of pyrocatechin is around pH 9.0, or so I believe from previous research, this would probably result in a much slower working developer.
Again, this is supposition since I have not actually tested the concept. If I am wrong may Neptune rain on me all week.
pH will depend on whether you use tech grade or industrial grade. With industrial grade, a 2% solution (by weight) is almost 10.5. That would be about the percentage of a 1+50 dilution since most of the stock is TEA. The major impurity in the industrial grade is diethanolamine.
Search for Dow Chemical. You will find a brochure covering MEA, DEA and TEA. Has more charts than you can shake a stick at.