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Article: Kodak D-25.

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    Kodak D-25.

    This formula is recommended by Kodak to produce extra fine-grain negatives than those processed with standard developers, albeit at some loss of film speed.
    Has anyone ever tried this formula?

    KODAK D-25

    Low to medium contrast fine grain film developer.

    Water, 125*F/52*C 750 ml
    Metol 7.5 grams
    Sodium Sulfite (anhydrous) 100 grams
    Sodium Bisulfite 15 grams
    Water to make 1 Litre.

    Mixing instructions: Add chemicals in specified sequence.

    Dilution: Use undiluted

    Starting point development time: 20 mins.

    Replenish with Kodak DK-25R.

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    Ian Grant's Avatar
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    Yes, I tested it over Easter, it's not bad at all,very fine grain, lowish contrast negatives though which weren't really ideal as it rained nearly every day I was back in the UK !! The weather made it difficult to tell how it really behaved tonally, but I felt it wasn't worth taking it any further.

    I think it's wrong for modern films, I tested Foma 100 & Delta 100, they both have good inherent fine grain anyway.

    Ian

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    This is similar to a diluted form of Patrick Gainer's Metolol or Rodinal using Metol.

    PE

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    Ian Grant's Avatar
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    It's not really similar at all, (well not to any form of Rodinal)

    The Sulphite content is more than ten times higher and the pH is close to 7 whereas old Classic/Rodinal must be nearer 9-10 (that's a very quick guess, but it should be roughly 11.8 before dilution).

    It does show quite nicely how Kodak switched techniques though to high sulphite levels for fine grain

    Ian

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    Quote Originally Posted by Ian Grant View Post
    It's not really similar at all, (well not to any form of Rodinal)

    The Sulphite content is more than ten times higher and the pH is close to 7 whereas old Classic/Rodinal must be nearer 9-10 (that's a very quick guess, but it should be roughly 11.8 before dilution).

    It does show quite nicely how Kodak switched techniques though to high sulphite levels for fine grain

    Ian
    Similar only Ian.

    It is, of course, lower in pH and higher in sulfite, but it is basically Metol and Sulfite which is an analog of Rodinal and Patrick's formula in substance and probably somewhat in function.

    PE

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    Ian Grant's Avatar
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    Actually Ron, it's a lessson on the extremes of a simple developer, one end is higher pH and acutance, the other with a low pH is very fine grain.

    In the case of Metol the middle ground, as in most practical is D23. But the there are good reasons it's not used by many.

    Ian

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    Ian Grant's Avatar
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    I'm nearly ready to do a flow chart of how some Kodak developers evolve. If we co-ordinate, I think the magic Triangle will make sense.

    Ian

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    Quote Originally Posted by Ian Grant View Post
    Actually Ron, it's a lessson on the extremes of a simple developer, one end is higher pH and acutance, the other with a low pH is very fine grain.

    In the case of Metol the middle ground, as in most practical is D23. But the there are good reasons it's not used by many.

    Ian

    After all of those years in the lab, I can say that "I know that!" and mean it. And that I know what was being done to lay the grounds for a more effective compromise.

    If you view the "triangle" of developer properties as flat, then by applying some new technology it can become effectively a "pyramid" bringing the points of the triangle closer in and making a developer that improves all 3 properties at once.

    PE

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    Quote Originally Posted by Photo Engineer View Post
    If you view the "triangle" of developer properties as flat, then by applying some new technology it can become effectively a "pyramid" bringing the points of the triangle closer in and making a developer that improves all 3 properties at once.
    Hey, applying 3 dimensions on a 2 dimensional object will get you kicked right out of Flatland. And don't go talking nonsense about that ficticious Spaceland place. I'm never going to believe it exists!
    Kirk

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

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    Well, if you don't believe me, then I guess you will just have to wait and read about it somewhere else.

    Buckaroo Banzai forever!

    PE

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