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Thread: Divided D-23, D-76: Can they be made truly divided ?

  1. #1

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    Divided D-23, D-76: Can they be made truly divided ?

    It has been pointed out that Divided D-23 is not really a truly divided developer: initial development occurs in Solution A, and continues in Solution B.

    The formula is given as follows:

    Solution A: 75 g Metol, 100g Sodium Sulfite, water to make 1 Liter
    Solution B: 2 g Borax, water to make 1 Liter



    Why can't we put the Sodium Sulfite in Solution B instead ? That's the same as D-23 itself. Is it because the film will develop in Metol alone ?

    Is Divided D-76 not truly a divided developer either ?

  2. #2

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    Re: Divided D-23, D-76: Can they be made truly divided ?

    Both DD23 and DD76 are divided developers, in that they are divided into two separate stock solutions. They represent one of 2 types of 2-bath development. In this type, some development takes place in the first bath, and is rapidly accelerated and completed in the second bath. In the other type, no development takes place in the first bath, usually due to insufficient pH. Both types are effective, but the first type is more flexible, allowing expansion development.

    You could make a D23 type 2-bath developer of the type in which no development takes place in the first bath by using enough sodium bisulfite in combination with the sulfite to lower the pH to a level at which the metol is inactive. Some sulfite is needed to preserve the metol, or the stock solution would quickly oxidize, and metol is only slightly soluble in water, so some sulfite aids in its solubility. You could try this:

    A solution-

    water 750ml
    sulfite 100g
    bisulfite 15g

    water to 1 liter

    B Solution-

    water- 750ml
    borax- 20g

    water to 1 liter

    The above is just a guess, as an example of one approach; bring down the pH of the A solution with bisulfite, and restore it in the B solution by increasing the borax. Alternatively, you might use 2g of carbonate instead of 20g of borax. A little testing will tell you what's required.

    My question is: why do you want to convert DD23 to the other type of 2-bath developer?

  3. #3

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    Re: Divided D-23, D-76: Can they be made truly divided ?

    Thank you !

    You make a wonderful point, and you ask a very insightful question indeed.

    Ed Buffalo says the following, which has really grabbed my attention:

    "So essentially, you develop in solution A until your high values are almost where you want them, then you place the film in solution B and develop until the shadow values are where you want them. If you are not experienced at development by inspection, you may have to do a little experimenting to get the times just right."

    With Divided Pyrocat, where development only occurs in Solution B, I have had to return the film to solution A on a few occasions, to further develop the shadows - so it has often ended up more like a 2-Bath process than a fully divided one.

    Using an Infra Red Viewing Device in the darkroom, it should be fairly easy to test Ed's 2-bath approach. I shoot sheet film and try to get each negative as close as possible to its desired appearance - before scanning, printing, or enlarging. The more adjustments we can do in the analog phases, the better.

  4. #4

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    Re: Divided D-23, D-76: Can they be made truly divided ?

    Ken,

    The two types each have their advantages and disadvantages. The advantages of the development in A bath-type are the flexibility of expansion development, and the even development. I personally favor this type. The advantage of the other type of 2-bath is that the A bath generally is better preserved and longer lasting, and since development occurs so rapidly, they produce very sharp negatives. This type is also less prone to blown highlights. The other side of that coin is that they often compress values into a muddy tonality. I like some sparkle in my negatives. The other downside to this type is the potential for uneven development, especially with staining developers.

    I'm currently working on a 2-bath developer of the develop in A bath type, for ultrafine grain and increased emulsion speed. It's very easy to make a 2-bath developer work, but much more difficult to make it work better than a standard developer. 5 or 6 years ago I experimented with ascorbate 2-bath developers, and was very happy with my results. My favorite was a metol/ascorbate/carbonate developer; no sulfite, no restrainer. I made the A bath up from dry chemicals before each session, and threw the remainder out after the developing session. I called it a Single Session approach, and I think it's very similar to the way Sandy works with his developers. I could develop a lot of film in a session without having to worry about replenishing, extending development times, or my developer quitting on me. I also didn't have to store a stock solution or wonder if it's still at full potency after the first session, because I just tossed it at the end of the session. It works great with my Jobo processor, because the solutions are pumped in and out of the containers for each batch of film developed, and everything is automated. I just fill the containers to begin, and then toss them after the session. The limitation on its practicality is that one should have a fair amount of film to process in a session- 10 rolls/8x10 sheets, or so is a good minimum. For smaller runs, one shot developers are more practical, for me. If you're interested, I still have a few of those formulas I was playing with. They each have their charms.

  5. #5

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    Re: Divided D-23, D-76: Can they be made truly divided ?

    Thanks for the further explanation !

    And thanks for your offer. For now, I plan to fiddle with Divided D-23, since I already have the ingredients on-hand. All 3 of them that is.

    Of course, if you feel that any of your earlier formulas represents a compelling improvement, I'd love to try them too. I'd love to hear more about their "charms", and I'm sure that others will too.

    These days I shoot FP4+ and HP5+ in 5x7. I'm less concerned with grain and acutance, than linear curves and good tonal control.

  6. #6

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    Re: Divided D-23, D-76: Can they be made truly divided ?

    Actually, the Divided D-23 formula I use is Barry Thornton's modified version, described here.

  7. #7
    Dave Karp
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    Re: Divided D-23, D-76: Can they be made truly divided ?

    Ken,

    Thornton changed his formula from 6.25g/L of metol to 6.5g/L after writing that article. The new formula is contained in his book "The Edge of Darkness." I corresponded with him after his death and he wrote to me that the formula in the book was his most current version and that it made a slight but noticeable difference. Whether .25g/L really makes a difference, I don't know, because I learned of his formula from the book and never tried the version from his website.

    Just a heads up. Judging by what I have seen of your work, it seems as if the formula is working just fine for you!

  8. #8
    Dave Karp
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    Re: Divided D-23, D-76: Can they be made truly divided ?

    As I think about it, it probably does not matter for you, Ken, because you are watching the development. It might make a difference when developing by time in trays or tanks, in the dark.

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    Re: Divided D-23, D-76: Can they be made truly divided ?

    Quote Originally Posted by David Karp View Post
    Ken,

    I corresponded with him after his death and he wrote to me that the formula in the book was his most current version and that it made a slight but noticeable difference.
    Was it through a séance or by Ghost-Post? Sorry David, I couldn't resist.

  10. #10

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    Re: Divided D-23, D-76: Can they be made truly divided ?

    Ken,

    The ascorbate 2-bath developers I experimented with were more like DD-76 than DD23, being superadditive developers. I used ascorbate instead of hydroquinone to take advantage of the fact that the ascorbate/phenidone or metol pairs don't require the presence of sulfite for their superadditive effects. Since ascorbate is a surface developer, the opportunity to improve acutance without sacrificing grain intrigued me. I decided to try splitting up the superadditive pair between the two baths, with metol in the first bath and ascorbate in the second. This approach was something of a compromise, since it required I use some sulfite in the first bath to preserve the metol, and allow for development to begin there, so hydroquinone could also be used. I think this is essential for developing brilliant highlights, and glowing mid tones. These ends were furthered by using a carbonate B bath instead of borax, and at a higher concentration. The carbonate B bath also kept development times conveniently short; when I'm developing a lot of film, I don't want to develop each batch for 15 minutes, and I suspect rapid forced development has a lot to do with the speed increases these kinds of developers produce. This formula is significantly different from the ones in your table above, and may be of no interest to anyone, but here it is anyway:

    M/C 2-bath

    A

    Sodium sulfite 25g
    metol 2.5g
    Water to 500ml

    B

    sodium carbonate 5g
    ascorbic acid 5g
    water to 500ml

    Development time in the A bath determines contrast. Develop between 3 and 5 minutes (for scenes of normal-high contrast) at 70F with continuous agitation. Longer development times will produce more contrast. Development in the B bath is almost instantaneous, continuing only until the metol absorbed in the emulsion is used up in the reaction with the ascorbate and carbonate. 1-2 minutes seems to be sufficient, but 3 minutes won't hurt anything.

    2-bath developers operate on the principle of excess, so they're very forgiving of sloppy formulation, penalizing mostly in the form of inefficiency, which does not reflect on image quality. This formula is not optimized, just a proof of concept, but the concept is sound because the results are very good. I've never seen another formula divided up this way, so I wasn't sure what to expect. I think the approach has potential. Like you, my primary concern is for consistent results, and excellent gradation, and any developer I test is compared to 510-Pyro, which sets a very high standard for consistency and gradation.

    Here's another idea I've never seen published, for a staining 2-bath developer of the type in which development begins in the first bath.

    A

    metol 5g
    sodium sulfite 100g
    water to 1 liter

    B

    sodium sulfite 0.25g (2.5ml of 10% solution, or 25ml of 1% solution)
    pyrogallol 0.5g (5ml of 10% solution in glycol is very convenient, or 5ml of Hypercat A solution for a catechol variant, in which case the sulfite should be omitted)
    sodium carbonate 2g
    water to 1 liter

    As you can see, the A bath is almost D23, and D23 could be used instead. Although D23 is a high sulfite developer, giving very fine grain and low contrast, not enough of the sulfite is carried over into the second bath to prevent staining. In this approach, the first bath is re-used for several films, but the second bath is used one-shot. The second bath contains the pyro, with enough sulfite to preserve it during development, and enough carbonate to force development to a rapid conclusion. That's the theory, anyway, I've not actually tested this developer. Catechol could be substituted for the pyro in the B bath, but the catechol would need to be increased, relative to the sulfite, since catechol is far more sensitive to sulfite than pyro is. The A solution of Hypercat would be a good option. If you want to test the above formula, you can be a pioneer! I won't be able to get into my darkroom for a few weeks, but when I do, I'll give it a try.

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