我按照柯达的说明书配制了ECN-2溶液（漂白液的配方是C-41），里面含有柯达抗钙剂NO.4和AF2000，如果我把ECN-2原液按照5倍浓度配成浓缩液，它的保质期是多久？
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Ask about my Homebrew ECN-2 shelf life
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Welcome to Photrio! It's great to hear that you're also working on color development - we share a hobby!
If your question is indeed about the developer, a few remarks:
1: You'd have to try if the developer will actually mix well at 5 times the working strength. You may run into a solubility limit somewhere, although I think you should be OK. Give it a try on a small batch to see if everything goes into solution, and also stays in solution even if the temperature drops to a little less in cold weather.
2: As to the lifetime of the developer: an ECN-2 developer has virtually no protection against oxidation. There's a tiny bit of sulfite in it, but this seems to be mostly there to avoid excess dye formation. So sacrificing it to protect the CD3 from oxidation will leave you with a developer that's no longer performing as specified. If you use water that's as free as possible of oxygen and you store the developer in a tightly capped, entirely full glass bottle, you may get a few weeks or even months of service life from it. It's hard to tell, since you're balancing on a thin edge and the point where things will start to fall apart will be unpredictable - and you'll only notice it as the negatives start to become thin and underdeveloped...
3: The Antical-4 and the Antifog-2000 probably don't help much/at all with the lifetime of the developer. The AF-2000 certainly will not; the antical may help a bit as it conceivable also binds with iron ions in the water, reducing their detrimental effect on the CD3. However, if you use distilled or demineralized water, you shouldn't have this problem to begin with.
4: If you want to store your ECN-2 developer for extended periods of time, consider adding an antioxidant that's compatible with a color process. The compound of choice would be hydroxylamine; this is also used in C-41 developer as well as some RA-4 developers. Hydroxylamine sulfate (HAS) is fairly easy to obtain; if you can get CD-3, surely you can also get HAS.
I believe that @lamerko on this forum has good experience keeping his ECN2 for a couple of weeks even without adding hydroxylamine. Perhaps he can chime in and share his experiences.
Just to be sure: you want to ask about your ECN-2 developer? And you intend to use a C-41 bleach?
If your question is indeed about the developer, a few remarks:
1: You'd have to try if the developer will actually mix well at 5 times the working strength. You may run into a solubility limit somewhere, although I think you should be OK. Give it a try on a small batch to see if everything goes into solution, and also stays in solution even if the temperature drops to a little less in cold weather.
2: As to the lifetime of the developer: an ECN-2 developer has virtually no protection against oxidation. There's a tiny bit of sulfite in it, but this seems to be mostly there to avoid excess dye formation. So sacrificing it to protect the CD3 from oxidation will leave you with a developer that's no longer performing as specified. If you use water that's as free as possible of oxygen and you store the developer in a tightly capped, entirely full glass bottle, you may get a few weeks or even months of service life from it. It's hard to tell, since you're balancing on a thin edge and the point where things will start to fall apart will be unpredictable - and you'll only notice it as the negatives start to become thin and underdeveloped...
3: The Antical-4 and the Antifog-2000 probably don't help much/at all with the lifetime of the developer. The AF-2000 certainly will not; the antical may help a bit as it conceivable also binds with iron ions in the water, reducing their detrimental effect on the CD3. However, if you use distilled or demineralized water, you shouldn't have this problem to begin with.
4: If you want to store your ECN-2 developer for extended periods of time, consider adding an antioxidant that's compatible with a color process. The compound of choice would be hydroxylamine; this is also used in C-41 developer as well as some RA-4 developers. Hydroxylamine sulfate (HAS) is fairly easy to obtain; if you can get CD-3, surely you can also get HAS.
I believe that @lamerko on this forum has good experience keeping his ECN2 for a couple of weeks even without adding hydroxylamine. Perhaps he can chime in and share his experiences.
if memory serves me well, HAS weakens the process of dye formation and therefore adding HAS to ECN2 developer without any further changes would result in thin negatives.
There it is:
C-41 without hydroxylamine
I've read multiple speculations that you can get away with no hydroxylamine in your developer if you use it as a one shot. Can someone confirm this from their personal experience?
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I wouldn't worry about this. In the words of Ron Mowrey when I approached him about the topic:
I don't use ATMP and AF-2000. It is possible that ATMP will help a bit, but I doubt it, as it would probably be quite useless as a chelating agent at pH above 10. Interestingly, this formula does not provide a preservative for CD-3 as there is in the C-41 process. Kodak estimates the shelf life of the solution to be about two weeks, but my conclusions are that it can easily survive a month in a tightly closed bottle. Even tonight I will do another batch of tests - for this purpose I will use an old working solution, about a month old. If you are interested - I am photographing the result and the exact date when I made the working solution - 500 ml, with two films already developed at the beginning and about a month left. I will release it with two more films from test productions together.
If you are making a 1:5 concentrate - it will probably start to crystallize after a short time. At least in my attempts to create such a concentrate, this is how it turned out.
If you want to keep a concentrate for a longer time, just make it in two parts - the alkaline elements (without CD-3 and sulfite) in one part, the rest in the other. This will extend the deadline. But it is best to separate the CD-3 in a third part - as a dry powder or in an acid solution (you can use a little metabisulfite, and in the end you will have to adjust the final pH).
If you are making a 1:5 concentrate - it will probably start to crystallize after a short time. At least in my attempts to create such a concentrate, this is how it turned out.
If you want to keep a concentrate for a longer time, just make it in two parts - the alkaline elements (without CD-3 and sulfite) in one part, the rest in the other. This will extend the deadline. But it is best to separate the CD-3 in a third part - as a dry powder or in an acid solution (you can use a little metabisulfite, and in the end you will have to adjust the final pH).
if memory serves me well, HAS weakens the process of dye formation and therefore adding HAS to ECN2 developer without any further changes would result in thin negatives.
There it is:
C-41 without hydroxylamine
I've read multiple speculations that you can get away with no hydroxylamine in your developer if you use it as a one shot. Can someone confirm this from their personal experience?
There is sulfite in the formulas - it is probably sufficient, despite its small amount. As far as I know, sulfite inhibits the formation of dyes more seriously than HAS. But the formula is balanced and maybe this suppression of the dyes is necessary...
Thank you very much. I divided the concentrated developer into three parts (liquid A + liquid B + CD3 powder). Liquid A contains sodium sulfite and sodium bromide, and the rest of the ingredients are in liquid B. Mix them with CD3 before use, which should be effective in extending the shelf life and ensuring the activity of CD3.
Because sodium sulfite is easily oxidized, I added 1.5g disodium EDTA, 1.5g phenolphthalein and 7g sodium bicarbonate to liquid A. Studies have shown that these ingredients can effectively inhibit the oxidation of sodium sulfite. I wonder if this can extend the shelf life?
With the current formulation being what it is, can I still add HAS to the solution? If so, which solution should I add it to?
I improved my process, details are in other replies, I wonder if this is effective?
I have Hydroxylamine HCl, can it be used instead of HAS?
This sounds like a lot of work to try and protect some sulfite; I'd rather lean towards just mixing the whole developer from powder at the time of use instead - which is indeed what I do.
I don't know if this addition will successfully protect the sulfite, really. I do know the phenolphthalein is very slightly acidic and the bicarbonate will also affect pH. Especially the addition of the latter will shift the pH of the final working strength developer. Have you measured this and ensured your developer is still close to the target pH?
As to the hydroxylamine HCl, you could try, but I also expect it'll affect pH which you may have to correct for by adding a little carbonate.
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