Anyone tried kodak e6 patent(US5948604)?

Rudeofus

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As you probably know, E-6 FD is one of the best B&W developers out there, that's why Kodak formulated it this way. Ron told me, that unlike HQ the oxidation product of HQMS doesn't have developer properties, and this causes HQMS to give better sharpness than HQ.

The only issue with E-6 FD is, that it is a very very powerful developer, which would develop your B&W film to normal contrast within less than a minute. The way to handle this is dilution: E-6 FD working solution diluted 1+9 makes a very decent B&W developer. I typically use it at 26°C for 10-12 minutes, and this gives me at least normally developed negatives. I like the development at 26°C, since at summer time not even my cold water always comes out colder than that.

Since I have - I believe - already mentioned this at least once, you can consider this a formula in the public domain :-D
 
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It seemed too simple to be true. Thanks for sharing your experience and perspectives.

Since I have - I believe - already mentioned this at least once, you can consider this a formula in the public domain :-D

 

River Mantis

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Hey. Nice to see you here. I used the information from these two patents. What I came to is redissolving the sulfonation product (it's almost solid at room temperature) in the 4x excess of sulphuric acid (in the described disilfonate synthesis process it's present from the beginning) at around 50º C and neutralising with stoichiometric amount of KOH in the form of 50% solution (yes, that's sketchy). After cooling to about 30º C the precipitate formed. Just filter it and wash with isopropyl alcohol. Got 47% this way, still not sure if I got any disulfonate contamination. And there is a hope that with the excess of acid (and some amount of water) sulfate just won't precipitate, as bisulfate is very soluble.
 

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  • US9801838.pdf
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  • US20110046412A1.pdf
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River Mantis

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CZA is the easiest here to synthesize. The method from 1893 (!) paper works surprisingly well, except that I kept the temperature at 135º because there is a clue in some later paper that above 150º the CZA (amide) may not form at all. Got about 20% this way
 

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  • W. J. Sell and T. H. Easterfield 1893.pdf
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River Mantis

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BTW do you remember the exact book?
 
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