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Sourcing Ferric Ammonium EDTA in the US

koraks

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pentaxuser said:
Are Andrew's ingredients and amounts all that are needed for perfectly satisfactory C41 negatives
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Yes. I've made similar developers. The differences in terms of image quality with official C41 formulas are very small.

pentaxuser said:
2. Does what Andrew refer to as CD-4 come with different names in Europe and the U.K.?
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No, it's referred to the same globally; as CD-4 or CD4. There are two CAS numbers that reflect a small difference, but the functional part of both molecules is the same. Shipping and duties can indeed make the material more expensive. I know of no domestic source in the UK. There are several sources in other parts of the world. They ultimately trace to China.

pentaxuser said:
3. Would Andrew's amounts that he used for one film actually be OK for several films if used again within say a few hours ?
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Yes; how many exactly will be a guess, but the capacity can be assumed to be the same as for commercial developers. This is usually considered to be in the 6-12 rolls per liter range.
 

River Mantis

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It indeed works perfectly for both ECN-2 and C-41 (there is a commercial product which uses it) and allegedly for E-6 (because why shouldn't it)
 

Rudeofus

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There are two aspects to Ferricyanide, and both are there because Ferricyanide is a stronger oxidizer than Ferric EDTA:
  1. potential staining, if Ferricyanide reacts with carryover CD-4. This is well addressed by your clearing bath.
  2. loss of archival stability. Film dyes are attacked by aerial Oxygen, therefore they are typically protected by reducing agents in the emulsion. These stabilizers are potentially destroyed by out of spec bleaches. You negatives/slides will look perfect for a few years, and then fading may set in long before a properly processed negative/slide would fade.

I have no idea, why Ammonium Ferric EDTA is so hard to obtain right now, not even Sigma Aldrich seems to offer it any longer. Artcraft sells all kinds of crazy chems but not this one. Very strange indeed. The good thing is, that the procedure for making it is not that involved, it's certainly easier than mixing all 7 E-6 bathes.
 

pentaxuser

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Thanks for the reply, koraks. The Dutch seller I found will sell quite a large packet of CD4 for the same delivery charge and that way or even possibly buying others chems from him would reduce the cost proportionately and it certainly is the "for sure" way to be rid of any uncertainty about shelf life in terms of the liquid kits if your use of colour is very limited

pentaxuser
 

RPC

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This has been addressed many times but I have yet to hear of any reports of any problems from long-time users of ferricyanide bleach for C-41. Personally, I have negatives more than 15 years old with no signs of change, and others even longer. Although not conclusive, it is encouraging, considering the aforementioned availability problems, and the wide use of scanning these days.

The rest of the process done properly is equally of concern.
 

Rudeofus

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Kodak and Ilford spent decades trying to make Ferric EDTA bleaches work with their color processes. In its basic form "Ammonium Ferric EDTA plus Ammonium Bromide at pH 5" it doesn't work well, so they researched bleach accelerators and other means to produce viable bleaches. Patent over patent was written and shoved though the USPTO.

There must have been quite some incentive to create really mild yet effective bleaches.
 

koraks

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pentaxuser said:
it certainly is the "for sure" way to be rid of any uncertainty about shelf life in terms of the liquid kits if your use of colour is very limited
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Yeah, that's what piqued my interest in DIY color developer mixing as well. Turns out that the commercially made developer stores very well, too. But it's a nice option to have at hand.

Rudeofus said:
There must have been quite some incentive to create really mild yet effective bleaches.
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I think much of it had to do with things unrelated to longevity of the negatives, though. Environmental and safety concerns, for instance.
 

Rudeofus

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koraks said:
I think much of it had to do with things unrelated to longevity of the negatives, though. Environmental and safety concerns, for instance.
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Environmental concerns could have been addressed much more elegantly and economically with persulfate bleaches, but these were never brought to C-41 and E-6.
 

RPC

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Well, since ferricyanide bleaches have never been officially tested with modern C-41 films (according to PE), all we have to go by is existing empirical evidence, which can be equally good. Take it for what you will.
 

GBS

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koraks said:
In the developer, it won't matter. This will affect solubility of a concentrate, but if you're mixing a working strength developer in one go, it doesn't matter and certainly doesn't explain any fog.
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It's funny becase we communicated in my thread 5 years ago trying to figure this out. I re-read that and you are correct: both C42 and C29 stained, no matter how much I washed between steps--including with a sodium sulfite step. Use an orion pH meter to get to my target. The only thing I didn't try was a sodium sulfite, metabisulfite and stop mixed together. But others have said they do fine simply with a handful of washes, so while helpful, I can't assume that's 100% necessary.
 

MTGseattle

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Adorama has a bunch of raw chemistry stuff in their "closeout" heading right now.
 

Rudeofus

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I have had my issues with stains (and all kinds of self mixed devs), and my current conclusion is: temperature and pH is most likely the culprit unless you messed up the formula. I tried to be extra smart and started at 40°C or mismeasured pH (wrong calibration buffer), and boom I had brown base.
 

MTGseattle

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Sorry. I should have clicked around and checked what "hazmat" meant to them. I figured it would simply mean slow, ground shipping only.
 
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