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  1. #21
    RobertoMiglioli's Avatar
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    Quote Originally Posted by Rudeofus View Post
    I can't tell you exact numbers, but on more than one occasion I have self mixed developers and used them after a few days without problems. I did not do any sensitometric tests, though, and my b&w devs worked at much lower pH than E6 FD. Note that most commercial developers are made with Dimezone-S, but their concentrates are expected to have long shelf lives. Testing will be the only way to find out, in other words, don't use it on your most important roll first if you use the dev after a week.
    Ok, thanks. Sorry, I didn´t understand what you say with "and my b&w devs worked at much lower pH than E6 FD". Could you explain better?

    Quote Originally Posted by Rudeofus View Post
    Look here for a recipe which comes from Fuji's patents and which has PhotoEngineer's official blessing. All Cd-x compounds will produce colors, but with slightly different hue and stability. Since the dye couplers in E6 are specifically made to work with CD-3, that's what I would use.
    Yes, you are right. I didn´t remember where I read CD2 or CD4 but now it sure is CD3. Thanks.

    Quote Originally Posted by Rudeofus View Post
    You will have problems getting the highly toxic 1-Thioglycerol, but it can be substituted by other compounds or left out at the expense of a bit longer bleach times. The stabilizer can be substituted by a simple recipe provided here. If you do that, you don't need the "Formaldehyde sodium bisulfite adduct" in the prebleach any more. The "Nitrilo-N,N,N-trimethylene phosphonic acid pentasodium salt" is a chelating agent which you can leave out if you use distilled water. Note that you will have to adjust pH if you change compositions!
    Fantastic! Thank you very much.

  2. #22
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    Quote Originally Posted by RobertoMiglioli View Post
    Ok, thanks. Sorry, I didn´t understand what you say with "and my b&w devs worked at much lower pH than E6 FD". Could you explain better?
    PhotoEngineer has posted on numerous occasions that Phenidone is unstable at high pH. This indicates to me that the destruction of Phenidone goes faster as pH is raised. Now if you look at the average fine grain B&W developer, you have pH of 8.2-9. If you look at E6 FD from the formula I linked to, you see pH 9.6. Therefore I would guess that E6 FD mixed with Phenidone is less stable than fine grain B&W developer mixed with Phenidone.

    I wouldn't worry about it going bad in a day or two, but I wouldn't use it over a much longer time span. Mix the chemistry (1l per 10-12 rolls of film) for as many rolls as you can process within one or two days, use it, then discard. Not much different from using a regular kit, just a bit less time to process a batch of films.
    Trying to be the best of whatever I am, even if what I am is no good.

  3. #23
    Athiril's Avatar
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    Quote Originally Posted by Rudeofus View Post
    PhotoEngineer has posted on numerous occasions that Phenidone is unstable at high pH. This indicates to me that the destruction of Phenidone goes faster as pH is raised. Now if you look at the average fine grain B&W developer, you have pH of 8.2-9. If you look at E6 FD from the formula I linked to, you see pH 9.6. Therefore I would guess that E6 FD mixed with Phenidone is less stable than fine grain B&W developer mixed with Phenidone.

    I wouldn't worry about it going bad in a day or two, but I wouldn't use it over a much longer time span. Mix the chemistry (1l per 10-12 rolls of film) for as many rolls as you can process within one or two days, use it, then discard. Not much different from using a regular kit, just a bit less time to process a batch of films.
    First Developer lasts quite a while, both the working tank and replenisher. Both in small amounts in glass bottles for home processing, and large floating tank for dip and dunk (which is what I do here at work now).

    There are two different CAS entries for CD-3, and both differ a bit, there is 25646-71-3 which is the one used on most products iirc, and there is also 24567-76-8.

    For 25646-71-3 the data on different chemical website databases vary for that exact same CAS number and the molecular weight varies between 200 something g/mol to 800 something g/mol depending on which site you're on, so it can be annoying. Both 24-567-76-8 should be the 800 something version with a lot more sulphuric acid attached to it.


    Here is one http://www.alibaba.com/product-gs/256474150/CD_3.html

    There's also some companies that'll do direct b2b in smaller quantities I think it's an Indian one, with it's own site not through Alibaba.
    Last edited by Athiril; 10-23-2012 at 06:43 PM. Click to view previous post history.

  4. #24
    RobertoMiglioli's Avatar
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    Quote Originally Posted by Rudeofus View Post
    PhotoEngineer has posted on numerous occasions that Phenidone is unstable at high pH. This indicates to me that the destruction of Phenidone goes faster as pH is raised. Now if you look at the average fine grain B&W developer, you have pH of 8.2-9. If you look at E6 FD from the formula I linked to, you see pH 9.6. Therefore I would guess that E6 FD mixed with Phenidone is less stable than fine grain B&W developer mixed with Phenidone.

    I wouldn't worry about it going bad in a day or two, but I wouldn't use it over a much longer time span. Mix the chemistry (1l per 10-12 rolls of film) for as many rolls as you can process within one or two days, use it, then discard. Not much different from using a regular kit, just a bit less time to process a batch of films.
    Ok, thanks. Understood.

  5. #25
    RobertoMiglioli's Avatar
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    Quote Originally Posted by Athiril View Post
    There are two different CAS entries for CD-3, and both differ a bit, there is 25646-71-3 which is the one used on most products iirc, and there is also 24567-76-8.

    For 25646-71-3 the data on different chemical website databases vary for that exact same CAS number and the molecular weight varies between 200 something g/mol to 800 something g/mol depending on which site you're on, so it can be annoying. Both 24-567-76-8 should be the 800 something version with a lot more sulphuric acid attached to it.
    Thanks. I read many times but I didn´t understand quite well. Which one should I use? 25646-71-3 or 24567-76-8?

  6. #26
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    25646-71-3

  7. #27
    RobertoMiglioli's Avatar
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    Quote Originally Posted by Athiril View Post
    25646-71-3
    Ok, thanks.

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