Accelerated age tests were performed on the products by Ryuji Suzuki.
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There is no compelling reason to believe that TEA would have any negative impact on image stability and our tests completely support this assertion.
Exactly. I've tested TEA, other alkanolamines (primary, secondary, tertiary and also N-substituted variants) in a very wide range of conditions from emulsion ingredient, developer ingredient, fixer accelerator/buffer, washing aid accelerator/buffer, and image protecting final rinse. Some of the tests used final rinse bath containing up to 1000ppm of alkanolamines (WAY higher than what's expected from inadequately washed material processed in Clearfix and Clearwash) and they were subjected to accelerated aging test. I've posted this a long time ago in the thread of Ag Guard substitute. Solutions containing alkanolamines and another agent (candidate compounds for active image protecting agent) were tested but of course a blank sample (treated with the vehicle solution without any active ingredient) was tested together in the same acceleration vessel. The fixer was my neutral rapid fixer, a fixer with published formula, containing no alkanolamines.
Alkanolamines have antioxidant functions but because my test condition is so severe there is no difference with or without alkanolamine at that level. That is, in my tests, there is no detrimental effect of alkanolamine residues at a concentration much higher than what's expected from inadequate washing. Plus, as I said before, there won't be any detectable level of alkanolamines in properly processed material. This undermines any criticisms arguing potentially detrimental effect of alkanolamines in fixer or washing aid.
I don't understand why this thread continues on such a clear non-issue. So far no one has raised any valid question as to any detrimental effect of alkanolamines. All it did was to increase the number of access to my silvergrain.org website referred from this thread (and that's how I noticed that this discussion was going on) and number of emails from former TF-4 users right after my posting here.
If you want to take the approach that only ingredients which have been used for 50+ years can be deemed to be 100% reliable, that is your choice. You suggest that the point will only be proved by "valid tests." Please tell me exactly what tests performed by which company you would accept to be valid and I will write to them to assertain the cost of having the tests performed. If you are willing to pay for half of the cost, then I'll happily pay for the other half ;-)
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I would welcome you publishing all of your results in full in this forum.
Well, if someone requests such a test from genuinely scientific concern and good intention, I suppose they will have their products tested together by a third party with no political or commercial bias and publish the results. And maybe you should consider more widely read journals and magazines not APUG to publish such results. Based on my own tests, I know how my formulae compare with other major competitors in each product category, so I'm not concerned.
When people suggested that we avoid TEA in fixers at EK, it may have simply been due to the fact that it was unknown, and would have entailed a large set of costly stability tests to prove its worth.
As far as I know, all fixer products Kodak offered in the past and present, including fix for color paper and films, are adjusted to acidic pH. The highest pH fixers are the ones for color materials but still below 7. In such formulae, triethanolamine offers no useful effect. Also, triethanolamine has no buffering capacity or fixing accelerating effect in such a low pH range. Most other alkanolamines are stronger base than triethanolamine and they would be even more useless in acid fixers. It is obvious Kodak never had any reason to use alkanolamines in fixers.
It is the ALKALINE FIXRES that can benefit from use of alkanolamines. For the pH of 7 to 8, where Clearfix and TF-4 operate, alkanolamine is a superior buffer than borax, requiring much less chemical, and also offering better biodegradability and much lower plant toxicity. A 100ppm of borate is a rough guideline of how little borate can be tolerated in water for plants. About 200x this amount of borate is in TF-4 working solution while none is in Clearfix.
So, I can validly ask the question, "what testing was done on image stability"? I don't mind if none was done, it merely leaves the question unaswered. There may be no effect.
I've posted these in other threads on image permanence, toning, etc. All tests were done with Clearfix and Clearwash as a part of the standard processing line, but some tests included specimen prepared with the fixer and washing aid formula published in APUG's formula section. Neither of the published formulae use alkanolamines. There is no difference between the types of fixers and washing aids. Test was sensitive enough to detect the concentration-dependent effects of residual thiosulfate, and other variables that I was mainly interested. Effect of toning, for example, is a really huge one and was unmistakably detected.
There is no effect if TEA is used in a developer, as that has been tested. But then, as I implied above, no developer ingredient has ever been shown to have a significant effect on B&W silver image stability, just fix and wash aid ingredients.
This is not true. In relatively recent studies by Konica scientists showed that the kind of antifoggants in the developer (as well as the emulsion) can influence the durability of image silver. However, such a technique is not very commonly used in commercial products because such image-protecting agents in developer can impair the fixing efficiency and this can lead to a bigger problem.
As for nitrosamines, some amines can form nitroso compounds directly from aerial oxidation and others from the presence of nitrites.
If you did the homework to find this out, you should also know that these reactions occur in acidic pH, fastest around pH of 3. pH of 3 is very common for food and beverages, but not in Clearfix and Clearwash.
Also, there are a number of agents that are known to inhibit nitrosamine formation by scavenging nitrites or other mechanisms. The most famous of these are ascorbic acid, erythrobic acid, and so forth. Many reducing as well as oxidizing agents can inhibit the reaction.
TEA contains up to 20% DEA (Diethanol Amine) which does form nitrosamines.
Maybe your source of TEA contains 20% DEA but not mine. In the past DEA-contaminated TEA was common for cheap technical grade stock. Now DEA is deliberately added to some technical grade TEA for some special purposes such as "low freezing" applications. This can be a problem if you buy chemicals from cheap surplus stocks.
In reality, I only use 99+ % pure triethanolamine with certificate of analysis from the manufacturer. Mine is made by Dow and I got it in Dow's original packaging. I also specify the same spec TEA in the production formulae I sent to the chemical plant where Silvergrain products are manufactured, and the industrial chemist there called me before buying his chemicals to confirm if he needed to spend extra money for that. I told him that it doesn't have to be Dow but it has to be just as good as mine. (Remember, I make my exhibition quality prints using my products from Digitaltruth and there is no reason to have inferior products for my own use.) According to the certificate of analysis from Dow, much of the 1% impurity is water.
It just does not happen unless you force it chemically. Even aerial oxidation does not cause it.
This is exactly the same in nitrosating alkanolamines. In silvergrain products, it doesn't happen unless you artificially and chemically force it to happen, and for that, you'll need to remove all ascorbates and much of sulfites, and then add a massive amount of strong acid to lower the pH to 3. In reality, this doesn't happen.
Again, the nitrosamine issue brought up by Bill Troop is way off the money and completely irrelevant.
Well, I must point out that the nitrogen in triethanol amine is quite alkaline and easy to protonate. This is what makes it a strong base. EDTA or the oxidized derivative of triethanol amine, nitrilotriacetic acid, act as if there were 4 and 3 acid groups respectively. In other words, the nitrogens are behaving entirely differently.
Now you are attacking alkanolamines are quite a bit stronger Lewis base than other amines and polyamines I named. Well, if that bothers you, what do you have to say about the ammonium ion which is massively present in all rapid fixers and some washing aids, such as Permawash? What about imidazoles commonly used as emulsion additives, and also used in many developers for machine processing?
In summary, I see there were 2 kinds of unfounded attacks from Ron Mowrey and Bill Troop against my Clearfix. (1) permanence is not proven. (2) nitrosamine formation is dangerous. In my past few posts here, I described sufficiently that both of these are non-issues. I'm not really interested in political discussion and I will leave this thread. If anyone has further scientific or technical questions, please contact me directly. If anyone has questions regarding product info, what other users say, etc., please contact Jon directly. In less than a year from its release, many people tried silvergrain chemicals and we also have several large scale institutional users. If there's any problems reported by users, large or small, Jon will know.