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  1. #31

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    Ian, any formula isn't same as Rodinal, becase original formula wasn't published. I think that you take away the discussion in the wrong direction and ignore my question regarding concentration of PAP in different version of EZ-Rodinal compared to other well known Rodinal-clones

  2. #32

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    Quote Originally Posted by Ian Grant View Post
    Andresen felt differently which is why Rodinal has no Chloride, it's enough to have a slight effect as these are equilibrium equations.

    Agfa and Andressen make a point of stating Rodinal contains only the free base in his publications so any formula based on the hydrochloride is not the same as Rodinal.

    Ian
    It is worth noting that the other formulas that arrive at p-aminophenolate via one of the 4-aminophenol derivatives (paracetamol, metol etc) all produce different salts, Na or K acetate in the case of paracetamol, for instance. I think while there may be very slight differences caused by these different salts, it is of rather academic interest at the dilutions the developer is used at. Put differently, I do not see much of an influence that isn't offset by a gain in affordability or ease of preparation. They all behave essentially like Rodinal. It is however important to get the final hydroxide balance correct. Some formulas have way too much hydroxide in them, and this causes severe fogging. It is also necessary to use potassium based chemicals for at least the sulphite or hydroxide (preferably both), otherwise the solubility of the aminophenolate is insufficient. There are many instances of only sodium being prescribed. These formulas are 20% deficient in active developer, and die quickly (+- 3 months). I am not sure why their longevity is not the same, but I can definitively say that my method produces long-lived parodinal. Any questions, PM me. I'd be happy to help.

    As for adding table salt to Rodinal: I wouldn't do that. The iodide content is far too high (and possibly varies wildly from product to product), and iodide is a stronger restrainer than bromide. So one can expect unpredictable results. If one must, then start by using AR grade NaCl, so at least you can benchmark with that first.

  3. #33
    Patrick Robert James's Avatar
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    I mixed up something based off of the EZ-Rodinal formula a year or so ago because I had the chemicals and I thought I would give it a go. I remember having to add more Sodium Hydroxide to get everything to dissolve, but I was using drain cleaner so I figured it wasn't really pure (although it said on the label it was). I added Benzotriazole to it as well. It has been working great all this time. I have been using Rodinal for two decades at this point. I can't tell the difference. The last bottle of Rodinal I had before this one (A&O I think) ended up having a ton of crystals in the bottom. I mean a lot! I ended up throwing it out.

    I also put sea salt (no Iodine) in Rodinal at times to kill some of the graininess with some films. It works fine. I think I use 30g/liter IIRC. It seems to lose some speed though which makes sense. From what I remember reading the salt acts on the exposed silver somehow to limit infectious development giving the finer grain. Some of the old fine grain formulas used salt. Maybe someone will chime in that knows more about it.

    Anyway I just wanted to relate my experience with it and give it the thumbs up.

  4. #34

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    Quote Originally Posted by Patrick Robert James View Post
    I think I use 30g/liter IIRC
    30g/l in diluted Rodinal?

  5. #35

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    Quote Originally Posted by dorff View Post
    There are many instances of only sodium being prescribed. These formulas are 20% deficient in active developer, and die quickly (+- 3 months).
    Off topic, but the rumor that the sodium form of PaRodinal has a short life is not true:
    http://www.apug.org/forums/forum37/8...ars-later.html

  6. #36
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    Quote Originally Posted by Patrick Robert James View Post
    I also put sea salt (no Iodine) in Rodinal at times to kill some of the graininess with some films. It works fine. I think I use 30g/liter IIRC. It seems to lose some speed though which makes sense. From what I remember reading the salt acts on the exposed silver somehow to limit infectious development giving the finer grain. Some of the old fine grain formulas used salt.
    30 g/l NaCl was supposedly used in Microdol for fine grain at the expense of emulsion speed. Note that Microdol X used an extra compound to avoid dichroic fog, so it would be interesting to know whether you ever ran into that issue with modern film.
    Trying to be the best of whatever I am, even if what I am is no good.

  7. #37

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    It isn't clear whether the purpose of the anti-silvering compound in Microdol-X was to avoid dichroic fog, improve sharpness by inhibiting physical development, or reduce sludging (I suspect it had more to do with sludging). Ilford's Perceptol (similar if not identical to Microdol) doesn't have dichroic fog problems. In the case of Microdol/Perceptol (which are based on D-23) I would not expect the additional solvent effect from the ~30g/L NaCl to cause dichroic fog problems. I think for that you really need a more powerful solvent (like the thiocyanate in DK-20 for example) and/or an even lower pH than Microdol.

    In a high pH developer like Rodinal which is essentially non-solvent to begin with I can't see how adding 30g/L NaCl would provoke dichroic fog.

  8. #38

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    In support of Ian here is an old formula for Rodinal. This is the formula which was collected from the Agfa Wolfen plant in 1945.

    Distilled water ………………………………………………………………… 340 l
    Paraminophenol …………………………………………………………………… 34 kg
    Potassium sulfite, 30% w/w at 55°C ……………… 558 kg
    Potassium hydroxide, 34% w/w………………………………… 50 kg
    Potassium bromide ………………………………………………………… 5.52 kg
    Agfa P.1347 antifoggant …………………………………………… 42 g

    As you can see the free base was used NOT the hydrochloride salt.
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  9. #39
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    Rodinal has always used the free base although at one time the free base was precipitated from the p-aminophenol hydrochloride solution and washed first.

    Excess Hydroxide was present in the manufacture and neutralised to the point where free base just began to precipitate.

    War time production may have had to make compromises so you can't read too much into 1945 formula.

    Ian

  10. #40
    Patrick Robert James's Avatar
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    Quote Originally Posted by Rudeofus View Post
    30 g/l NaCl was supposedly used in Microdol for fine grain at the expense of emulsion speed. Note that Microdol X used an extra compound to avoid dichroic fog, so it would be interesting to know whether you ever ran into that issue with modern film.
    I haven't seen any dichroic fog, but I also used Benzotriazole when I originally mixed it so that may be a factor.

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