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  1. #1

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    Developer secrets

    Just a quick question. Are there any real secrets in developer formulas? By that, I don't mean things not known by the general public. I mean, do all the major companies know the formulas of the other company's developers?

    I am assuming that most companies have liquid chromatographs, mass spectrometers, and other analytical equipment available that would allow them to analyze competitive formulas.

  2. #2
    Ian Grant's Avatar
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    It's extremely difficult to fully analyse and determine whats in a specific developer, but you can get quite close. However a great many developers are found in Patents or Scientific Journals anyway. So for instance Ilford had to use a different approach when formulating Ilfotec HC (& LC) to get around the patent for HC110.

    Ian

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    There are specifics of manufacture that are not widely known in the trade. Kodak has a lot of trade secrets that they do not make public. And, to add to that there are chemicals in use that are not publicized or techniques that are very unusual. Along with that are formulas that were never released to the public.

    We cannot duplicate some of this outside of a large industrial facility. One specific example is making HC110 syrup. This is done by charging a specific quantity of Sulfur Dioxide gas into TEA/DEA and then mixing it with another batch of TEA/DEA that has been charged with HBr gas. This supplies the Sulfite and Br ions but in an inactive form until the syrup is mixed with water. Another example is the preparation of D76 or Dektol powders in which the two main ingredient classes are separated from each other by an encapsulation technique that is quite confidential.

    PE

  4. #4

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    Quote Originally Posted by Photo Engineer View Post
    One specific example is making HC110 syrup. This is done by charging a specific quantity of Sulfur Dioxide gas into TEA/DEA and then mixing it with another batch of TEA/DEA that has been charged with HBr gas. This supplies the Sulfite and Br ions but in an inactive form until the syrup is mixed with water. Another example is the preparation of D76 or Dektol powders in which the two main ingredient classes are separated from each other by an encapsulation technique that is quite confidential.
    Both of these sound like techniques to enhance the keeping properties - very important for a retail product that is likely to sit on the shelf for a while - rather than anything that affects the sensitometric behavior of the fresh product. Is that right?

  5. #5
    Photo Engineer's Avatar
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    It has two effects. It gives very high stabilty and also allows for very great concentration to make a very concentrated syrup. This means that you are not shipping water, but rather almost 100% active chemistry. However, this is almost impossible to do on smaller scales.

    It has no effect on sensitometry as the effective result is that the SO2 becomes the equivalent of Sodium Sulfite and the HBr becomes the equivalent of NaBr in water.

    PE

  6. #6
    Ian Grant's Avatar
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    As Ron says different companies have there own approaches so while ID-11 & D76 are similar, they were once identical. Likewise D72 - Dektol and Bromophen which are eqivalents, the liquid version of Dektol differeing from the powder, one usingMetol the other Dimezone.

    Companies weren't/aren't interested in making exact copies of competitors products rather being able to offer a suitable alternative. ID-11/D76 is perhaps the only exception and was a 1930's developer equivalent of Open Source software, manufactured by just about every company to allow consistent processing of Cine films.

    Ian

  7. #7
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    Yes, Ian is correct. I might add that Liquidol and Dektol act quite alike in sensitometry and image tone, with just a slight iimprovement in shadow detail with Liquidol, but they are formulated quite differently. You can get to the same place or to a roughly similar place by different routes.

    Liquidol could be changed to be exactly equivalent to Dektol by tweaking. Bill and I thought the results in the shadows were good enough as they were to merit the stamp of approval. Other properties are different though, but this is not the venue for this sort of discussion.

    PE

  8. #8

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    Quote Originally Posted by Photo Engineer View Post
    Other properties are different though, but this is not the venue for this sort of discussion.

    PE
    ???

  9. #9

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    Quote Originally Posted by Photo Engineer View Post
    ...with just a slight iimprovement in shadow detail with Liquidol... Bill and I thought the results in the shadows were good enough as they were to merit the stamp of approval. Other properties are different though....
    PE
    What is the sensitometric equivalent to "a slight iimprovement [sic] in shadow detail..." ?

    Higher shadow contrast?

  10. #10
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    Lower contrast in very high density areas allows you to see more detail in blacks and near blacks. Higher contrast reduces the difference between blacks and therefore decreases detail. This may appear counterintuitive at first glance, but it is true.

    PE

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