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Thread: making D-76

  1. #11
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    D76

    I think D-76 is the best developer of all time. When you make it up, it is a bit like draught Guinness, you have to wait for it. But once made you can't go wrong.

  2. #12

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    I always mix my own D-76. I can scale the amount to what I need. It takes less than 10 minutes to mix up to a liter of stock, and not much longer for larger batches. Most of the time is spent dissolving the metol, with the sulfite a close second. The stock solution keeps decently well, but I usually just mix what I am going to use that day. You don't need to use hot water to mix up a 1+1 diluted solution, so you can use it right away. (However, some people believe that mixing up stock and letting it stand for a day gives more consistent results.)

  3. #13

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    D-76 Formulas

    I have been mixing D-76 for a few years with complete success. You can get chemicals from photographer's formulary and the supermarket. Just one suggestion, if you use the developer right away, you can use the original formula but if you want to store it for a while (up to one year) use the buffered formula with boric acid in it. The original formula changes activity with storage time, believe it or not, it gets more active with time and your contrast will come out too high. I use the buffered formula from Anchell's book. Dissolving boric acid is slow, but I use a stirring hot plate which removes most of the pain of dissolving powders. Some say the D-76 you buy today is actually the buffered version, but I don't know. Good luck and have fun.

    Best regards,
    Chris

  4. #14

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    Quote Originally Posted by Gerald C Koch View Post
    No, they are not going to go airborne -- think of crystalline powders such as table salt. Besides. you are not going to be mixing powders together. You will be dissolving them in water in the order that they are given in the formula. When one chemical has dissolved then you can add the next one.

    The only exception is when dealing with Metol. In this case a small amount of the sodium sulfite is dissolved, then the Metol and then the rest of the sulfite. This is done because Metol dissolves only with difficulty in concentrated sodium sulfite solutions.
    Gerald, I've always been curious about this. How much more difficult is it to dissolve Metol in water without the "pinch" of sulfite that is usually recommended? I'm asking because I use a lot of Perceptol which comes in two parts. Part B lists Sodium Sulfite on the packet but I don't think there is any Sulfite in Part A, which is the Metol, and Part A seems to go into solution quite quickly/easily.

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    Hi Michael.

    The pinch of sulfite is to remove any oxygen from the water and to protect the Metol while it is dissolving. This is a small problem but using the pinch prevents the Metol from becoming discolored. It doesn't help with the Metol dissolving. Once the Metol is dissolved the rest of the sulfite can be added.

    Trying to dissolve Metol in concentrated sulfite solutions is difficult needing heat and lots of stirring. Excess stirring introduces oxygen into the mixture and is best avoided.

    In "two bag" formulations there is usually some sodium sulfite in bag A. Besides the problem during mixing the sulfite also preserves the developing agents while in the bag. As PE pointed out, Kodak spent a good deal of research on packaging and holds quite a few patents on this matter. This allows them to use a single bag package.
    Last edited by Gerald C Koch; 11-13-2011 at 11:58 AM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  6. #16

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    I mix the Haist D-76H and find it works well at regular D-76 times. BTW, if the dry metol goes slightly yellow in the bottle, is it still good?

  7. #17

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    A slight discoloration of the Metol is OK but it shouldn't be brown. It will develop a gray or purple color when exposed to light. This is also OK.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  8. #18

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    Quote Originally Posted by Gerald C Koch View Post
    Hi Michael.

    The pinch of sulfite is to remove any oxygen from the water and to protect the Metol while it is dissolving. This is a small problem but using the pinch prevents the Metol from becoming discolored. It doesn't help with the Metol dissolving. Once the Metol is dissolved the rest of the sulfite can be added.

    Trying to dissolve Metol in concentrated sulfite solutions is difficult needing heat and lots of stirring. Excess stirring introduces oxygen into the mixture and is best avoided.

    In "two bag" formulations there is usually some sodium sulfite in bag A. Besides the problem during mixing the sulfite also preserves the developing agents while in the bag. As PE pointed out, Kodak spent a good deal of research on packaging and holds quite a few patents on this matter. This allows them to use a single bag package.
    Ah. Thanks for the clarity on this. It didn't occur to me such a small amount of sulfite would have a marked effect on preservation of the Metol during mixing. For Perceptol, when I pour in the Metol the solution takes on a slight pink/tan cast. Once I add in packet B (Sulfite, Sodium Chloride) it becomes colorless.

    One more question on Perceptol, Gerald. The third agent in packet B is Sodium Tripolyphosphate. Is this a sequestering agent?

  9. #19

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    Yes, this chemical is one of a family of condensed pyrophosphates that sequester calcium and keep it in solution. Another chemical often used is sodium hexametaphosphate, tradename Calgon.

    There is a funny story about Calgon. The Calgon company used to market two forms of this chemical for retail customers. One was the pure chemical and there was also Calgon Bath which contained soap and a perfume. One poster complained that his developer foamed badly with use, but it did smell good.
    Last edited by Gerald C Koch; 11-13-2011 at 12:28 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  10. #20

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    Thanks for the help.
    Michael

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