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  1. #1
    Ian Grant's Avatar
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    Modern Rodinal Substitutes Part II

    Apologies for having to start a new thread but I can't read or even access the first to reply to posts.

    So with a bit of telepathy

    Quote Originally Posted by Kirk Keyes View Post
    Well, there's a problem there, as it's really hard to measure pH accurately when it gets much above 12.5 or so. You have to start getting special electrodes and the like.

    But for MSDS work, it doesn't have to be too precise.
    __________________
    Kirk

    A point that's being missed is that A&O give a figure of 2.7% Potassium Hydroxide not 3% in older Agfa MSDS.

    The pH is around 14 sure, but the actual requirement is the pH of the working dilute solution rather than the concentrate which is given elsewhere as pH 11.55, which I commented on in the first post of the thread.

    Way back Ron (PE) mentioned adjustments to Rodinal before bottling, the question we need to ask is are they adjusting on the basis of the concentrate, or also doing some tests on a dilute sample, as this will be a far more accurate indicator.

    Can someone please post a link to this continuation on the original post.

    Ian

  2. #61
    Photo Engineer's Avatar
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    Patrick;

    My literature reports that there have been explosions associated with working with Metabisulfite due to its strong reducing power. I would prefer to work with sulfite myself.

    IDK about your developer but the reports here vary saying that the Metol version is good or bad depending on the individual. I think more tests are indicated.

    PE

  3. #62
    Ian Grant's Avatar
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    Patrick, there's something nagging away in my mind about Metabisulphite. Yes the early Rodinal type formulae used it & Hyroxide to form Sulphite, at one point that was the best way of producing the Sulpite in solution.

    We've had this discussion before but there is also the subtle difference between Bisulpite & Metabisulpite, and last time I was in the UK I found a reference and short extract from a Kodak paper on the subject, which I posted here on APUG. Kodak Bisulpite is in fact a mixture of Bisulphite & mainly Metabisulphite, and Kodak were referring to the interchangeability of their Bisulphite with Metabisulphite. J.T Baker sell both forms in bulk.

    At some point before WWII Agfa began using Sulphite, I think something else is happening as we also know that around then they were also adding anti-foggant.

    The referance to Oxygen scavenger yesterdaym (Ammonium Bisulphite) was what triggered my thought, and knowing that Metabisulphite in a developer helps cut dichroic fog.

    In the wine trade Metabisulpite solution is used as an anti-oxidant, and steriliser as it's more powerful than Bisulphite, but no-one seems to explain why satisfacorily, It has a lot to do with free SO2.

    Ian

  4. #63
    Ian Grant's Avatar
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    Quote Originally Posted by Photo Engineer View Post
    Patrick;

    My literature reports that there have been explosions associated with working with Metabisulfite due to its strong reducing power. I would prefer to work with sulfite myself.

    PE
    In our developer applications Metabisulphite is perfectly safe. Over the years I've used many metric tonnes, I'd get through 25kg every couple of days and we were adding it to Aqua Regia (Nitric & Hydrochloric acid) to generate SO2.

    Home winemakers regularly use Metabisulphite in their kitchens, either as a powder or as Camden tablets.

    Metabisulphite is also used in ID-13, D153 and equivalents, the Caustic Hydroquinone graphic arts developers

    Ian

  5. #64
    Ian Grant's Avatar
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    Quote Originally Posted by Photo Engineer View Post
    Ian;

    I was comparing two developers with very similar structures under identical conditions in my thinking. Phenidone and Dimezone-S are basically cyclic hydrazine derivatives. In alkali, the Phenidone ring opens and becomes inactive much more rapidly than Dimezone-S and the activity is somewhat lower. For this reason, Kodak used Dimezone-S in the PR-10 pods due to the high alkali content and the need for quick development.

    So, for a quick OTOMH answer, those are two to compare, and if you do, (and which I have done), the Dimezone-S comes out ahead.

    PE
    Yes Phenidone does hydrolyse and G.I.P.Levenson and L.F.A.Mason state that because of this Kodak & Ilford used Dimezone & Phenidone -Z which is why both Kodak & similar Ilford developers using them have a good shelf life.

    Ian

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    Ian - do you know if what Ilford sells in dry powder (125 g bottles I think it was) back around 1980 as "Phenidone" is actually Phenidone or Phenidone-Z?
    Last edited by Kirk Keyes; 09-01-2009 at 12:57 AM. Click to view previous post history.
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  7. #66
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    There is an advantage of the liquid concentrate when you know exactly how much sulfite you need. When you are experimenting, You must prepare the solution you think you want in order to test it. If you decide you need to double the sulfite, adding the liquid concentrate will change the total volume more than would adding the solid sulfite, or even the KOH + bisulfite.

    In the meantime, I got some of the 45% w/w solution and mixed a batch with 222 grams of the sulfite solution, 22.7 grams KOH and 34 grams of Metol in water to make a liter. I'm too sleepy now, at 2:00 AM, to do any more.
    Gadget Gainer

  8. #67
    gainer's Avatar
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    Quote Originally Posted by Ian Grant View Post
    Patrick, there's something nagging away in my mind about Metabisulphite. Yes the early Rodinal type formulae used it & Hyroxide to form Sulphite, at one point that was the best way of producing the Sulpite in solution.

    We've had this discussion before but there is also the subtle difference between Bisulpite & Metabisulpite, and last time I was in the UK I found a reference and short extract from a Kodak paper on the subject, which I posted here on APUG. Kodak Bisulpite is in fact a mixture of Bisulphite & mainly Metabisulphite, and Kodak were referring to the interchangeability of their Bisulphite with Metabisulphite. J.T Baker sell both forms in bulk.

    At some point before WWII Agfa began using Sulphite, I think something else is happening as we also know that around then they were also adding anti-foggant.

    The referance to Oxygen scavenger yesterdaym (Ammonium Bisulphite) was what triggered my thought, and knowing that Metabisulphite in a developer helps cut dichroic fog.

    In the wine trade Metabisulpite solution is used as an anti-oxidant, and steriliser as it's more powerful than Bisulphite, but no-one seems to explain why satisfacorily, It has a lot to do with free SO2.

    Ian
    My wine-making friends sell their's. They smoke the insides of the bottles with a sulfur candle. The powers that be make them put "Contains sulfur" on the label.

    As Scripture says, after perversion by me, It's not what goes into the mouth (of the bottle) but what comes out that defiles a (photographer) person. If we put in bisulfite or the British bisulphite along with KOH our film will see K2SO3.
    Gadget Gainer

  9. #68
    Ian Grant's Avatar
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    Kirk, some where I have references to "Commercial Phenidone" as Phenidone-Z.. Plain Phenidone doesn't keep at all well in alkali solutions, and is partly soluble in water, where as Phenidone-Z has poor solubility unless the solution is alkaline and keeps well.

    A problem is Ilford use "Phenidone" as a generic "Trade name", but Mason of Ilford discusses the problems of Phenidone then goes on to state (Photographic Processing Chemistry 966/1975) "In order to reduce this trouble, two 4-substituted derivatives were introduced commercially a few years ago "Phenidone-Z" Ilford "Dimezone" Kodak. (His editor was Levenson from Kodak)

    In practice Ilford only began using "Phenidone" commercially around 1951/2 because of the problems, and Ilford's PQ developers etc keep well in concentrate form so were definitely not using plain Phenidone.

    I have Ilford's 1960 trade price list in front of me and Phenidone is sold in 10g -500g quantities, but doesn't say what form, that may well ahve been a trade secret. As I said earlier the Phenidone I had adted 1962 kept exceptionally well over 40 years, and there was no discernible difference in activity when I bought fress stock 2 or 3 years ago.

    It's quite possible Ron (PE) used "Plain Phenidone" at Kodak in his tests against Dimezone

    Ian

  10. #69
    Ian Grant's Avatar
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    Quote Originally Posted by gainer View Post
    If we put in bisulfite or the British bisulphite along with KOH our film will see K2SO3.
    That's the theory & practice but Metabisulphite is not Bisulphite and something more happens when it's dissolved, there's far more free SO2

    True Bisulphite (powder) can only be bought as a lab reagent and it's unstable.

    Ian

  11. #70
    Ian Grant's Avatar
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    Quote Originally Posted by Kirk Keyes View Post
    Ian - do you know if what Ilford sells in dry powder (125 g bottles I think it was) back around 1980 as "Phenidone" is actually Phenidone or Phenidone-Z?
    That's a different question to the one I answered, you've re-written the post

    It'll be Phenidone-Z, (unless they changed to another derivative), but my recent Phenidone behaves the same as my 1962 Phenidone in Film & Print devs.

    Ilford published Phenidone Formulae in the Feb 12th 1954 issue of the British Journal of Photography.

    Ian



 

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