The Ferric EDTA is an oxidant, no matter what gas is used for storage.
They may use a stabilzer, but whatever it is, it will reduce the oxidation potential of the Ferric ion and thereby slow the blix. If it slows the blix, then you have more retained silver or you must use longer fix times.
I know of several chemicals that can be added to a blix that would essentially turn it off totally! It also makes it as stable as a hypo solution of the same composition without the iron salts. And, it makes it only a fix. That can be done, and no one would notice the difference except for having retained silver. It would make it a very expensive and complex bleach bypass.
No, the bottom line is that both developer and blix should be multipart.
The developing agent begins to decompose when dissolved in alkali. Kodak and others store the developing agent in an acidic part that is neutralized when mixed with the other two parts. The Hydroxyl Amine in the developer should also be stored as an acid for best keeping, or at least in a neutral solution.
I'm afraid that Tetenal is going to run into shelf keeping problems with these single part kits. We already see an example here, and I think there have been other threads on this as well.
I sent email to Tetenal:
Subject: Defective RA-4 blix
I'm very disappointed in your product TETENAL RA-4 print kit 2,5l. There should be no reason to use monoconcentrate to help mixing. The blix has oxidant and reductant together and has too short shelf life in one concentrate.
I have used two kits and the blix has somehow worked only occasionally. It has crud in it and the bleaching and fixing power is not sufficient. It can die before even getting to the final user. You should use two concentrates.
I've now re-bleached and re-fixed a lot of my prints. Some of them are fine, some are not. This has caused me much work and hassle.
It may be true that the problem is known and accepted, because with normal RA-4 prints the problem may not be visible for an "average customer" (hobbyist) - at least when the print is examined in subtle room lighting for short periods. But the reversal process shows the problem in its full glory since all the silver is developed...
A funny thing is, I tried bleach bypass processing for some RA-4 prints using Agefix and then compared the result by using this same exhausted blix. I noticed no obvious difference in the final result and I was wondering, why the images looked almost exactly the same .
Bleach bypass will fix the coating and leave silver in image areas. This degrades the color, sharpness and grain. An exhausted blix which can still fix, can have the same effect, but if it cannot fix properly then the image is just like a B&W image which is unfixed.
If the fixer is not of the proper pH in bleach bypass, or when using a bad blix, then the dyes can suffer in both hue and stability.
I got the same problem repeatedly. It seems that it happens when the blix concentrate is not quite fresh. Unfortunately there is no way of telling before you get the kit (you don't need to mix the crud shows at the bottom of concentrate) as there is no expiry date on it.
Originally Posted by hrst
I've been unable to clean kodak paper with E surface and its quite a chore to wipe it of F surface. Since that I've switched to minilab chemistry. If you find someone to share a bigger package or some minilab operator willing to sell some you get 5l of working solutions for the price of the amateur kit. And no crud as a bonus.
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I'd gladly use Kodak chemistry but it seems it is not available in small packages here while shipping from abroad makes it to expensive. I don't print color very often so I do not have much choice.
If commercial chemistry isn't available, then consider using scratch-mix bleach and fix. There are many formulae available. While bleach does take a bit of rocket science to ensure archival dyes, fixers are quite standard and easy to mix from scratch. As PE has noted here before, blix one might consider blix bad when it is mixed. Separate bleach and fix is clearly the way to go.
By denying the facts, any paradox can be sustained--Galileo
Fujihunt produce a small RA-4 5 litre kit which might be easier for you to obtain.
From images I found on Google, I see that the Tetenal Colortec RA-4 kit has blix in two separate concentrates in the 5 liter version, but the 2.5 liter version has just one. Maybe they separated concentrates in the bigger version to allow for better splitted mixing?
I am going to get the 5 liter one.