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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. #21
    gainer's Avatar
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    [QUOTE=Kirk Keyes;853451]Pat - I'm pleased you've taken to the world of pdfs so quickly, but I think you might find you can post photos as jpgs that look better than photos as pdfs.

    QUOTE]

    Here are .jpg files, overall and detail. These are from direct scans of the negative. I think you are right. Even at much reduced file size they look better.
    Attached Thumbnails Attached Thumbnails Metolal Test 2.jpg   Test 2 Detail.jpg  
    Gadget Gainer

  3. #22

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    I think that looks better - no artifacts from the pdf. You posted a photo in the Part I that the pdf had mangled so much it looked like it had been transmitted via a 1950s facsimile machine!
    Kirk

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

  4. #23

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    Patrick,

    The rate of aerobic oxidation of ascorbic acid has maxima at pH 5 and 11.5 (google ascorbic acid oxidation pH lester packer).
    If that is true the ascorbate version at pH 14 will probably not be as resistant to oxidation as Rodinal.
    However it may show considerable increase in film speed.
    Is there a formula to test yet?

  5. #24
    cmo
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    Quote Originally Posted by Ian Grant View Post
    I suddenly realised why you want a developer that's non injurous to health

    More seriously I have had a thought and it might just work. Answering Kirk's pH point made me think of a developer I've used highly dilute and yes it gave excellent acutance etc and with modification it would almost be drinkable.

    This quote came back to mind from earlier in the thread:


    As for developers, it is probable that the next few years will see the introduction of a series of developing agents that that can actually be eaten if desired. Some, chemically related to Vitamin C, are available now though at enormous cost. One call almost see the advertisement of the new Zero-Grane 999 (1960 A.D.) ----- "Try Zero-Grane 999. Non-poisonous. Enlargement to 999 diameters, miraculously discovered by George Gizzlewski after 84 years of painstaking research. If it won't develop your negative, take two teaspoonsful after each meal. It puts spring in your step and a light in your eye. $10 per 2 oz. bottle sufficient for 89 rolls of film."


    Edmund Lowe, 1939


    Ian
    I am a coffee addict...

    Maybe you could also think about a Rodinal-like Caffeinol+C potage...

    That would also answer my eternal nagging that a standardized, reliable no-surprise Caffeinol would be the next great thing.

    Here is my dream:

    A developer based on caffeic acid and/or vitamin C. It should be highly concentrated, and of course it should last forever and make full film speed or even pushing possible. We need two versions:

    - High acutance, lots of grain, like Rodinal
    - High acutance, no grain, like Perceptol

    That will not be too difficult, right?

  6. #25

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    Sorry to butt in but I've never used Perceptol and am interested in its "high actance / fine grain" properties. I million years ago when I was processing my own film I used Rodinal and LOVED the acutance but had to put up with the grain.

    Does Perceptol possess as much acutance as Rodinal?

    Is the grain truly that much finer than Rodinal?

  7. #26
    Ian Grant's Avatar
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    Only at 1+2 or 1+3

    I can't comment on the grain, except yes it's fine with Perceptol, but I always got fine grain with Rodinal too using APX1oo, APX25 and Tmax 100.

    Ian

  8. #27
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    [---- "Try Zero-Grane 999. Non-poisonous. Enlargement to 999 diameters, miraculously discovered by George Gizzlewski after 84 years of painstaking research. If it won't develop your negative, take two teaspoonsful after each meal. It puts spring in your step and a light in your eye. $10 per 2 oz. bottle sufficient for 89 rolls of film."[/I]


    Edmund Lowe, 1939
    ******
    Made my morning. Lowe had a sense of humor. I must needs now chuckle each time I use some FG-7.


    Ian[/QUOTE]
    John, Mount Vernon, Virginia USA

  9. #28
    cmo
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    Quote Originally Posted by Mike1234 View Post
    Sorry to butt in but I've never used Perceptol and am interested in its "high actance / fine grain" properties. I million years ago when I was processing my own film I used Rodinal and LOVED the acutance but had to put up with the grain.

    Does Perceptol possess as much acutance as Rodinal?

    Is the grain truly that much finer than Rodinal?
    Perceptol has a LOT less grain than Rodinal. Well, so do XTol and all other developers. If you want grain try APX 400 in Rodinal and push it to 1600.

    Ilford Perceptol alias Kodak Microdol-X is not too bad in terms of acutance, and it becomes pretty good at 1+3. But with most films you lose some speed. And of course it is not as comfortable to use as Rodinal and does not last for centuries.

  10. #29
    gainer's Avatar
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    Quote Originally Posted by Alan Johnson View Post
    Patrick,

    The rate of aerobic oxidation of ascorbic acid has maxima at pH 5 and 11.5 (google ascorbic acid oxidation pH lester packer).
    If that is true the ascorbate version at pH 14 will probably not be as resistant to oxidation as Rodinal.
    However it may show considerable increase in film speed.
    Is there a formula to test yet?
    I wasn't thinking of such a high pH. I want to stay below the point where ascorbates alone are active. Ascorbate will still serve to regenerate oxidized Metol at pH = 8.7, at which pH it produces results like those of sulfite. This is the reason it works in place of sulfite in the Pyrocat developers that are dissolved in glycol. Its function there is to allow Phenidone or p-aminophenol or Metol to interact synergistically with the catechol when water is added to the glycol stock as sulfite does in the water stock.
    We think of Metol-hydroquinone as a superadditive pair, but the superadditivity does not work without sulfite or ascorbate.
    The developing agent in Rodinal is potassium aminophenolate with sulfite preservative. It is more an analog of D-23 than anything else, if you choose to look at it that way. If we could buy (maybe we can) potassium p-aminophenolate, we could probably get the same result as Rodinal by putting it in a solution with sulfite, and not worry about how the phenolate was manufactured. Now substitute potassium ascorbate for the sulfite and see what happens.
    Gadget Gainer

  11. #30

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    Quote Originally Posted by cmo View Post
    Perceptol has a LOT less grain than Rodinal. Well, so do XTol and all other developers. If you want grain try APX 400 in Rodinal and push it to 1600.

    Ilford Perceptol alias Kodak Microdol-X is not too bad in terms of acutance, and it becomes pretty good at 1+3. But with most films you lose some speed. And of course it is not as comfortable to use as Rodinal and does not last for centuries.
    That's just it though. I want the best of both worlds... extremely high acutance and fine grain. By far, I care most about acutance and would never give that up for fine grain. I'll just shoot the biggest film I can carry the equipment for.

    If there is a very high actance developer (at least as good as Rodinal) but with finer grain then I would certainly give it a try.

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