B&W Negs/Color Slides Variables

Discussion in 'B&W: Film, Paper, Chemistry' started by davetravis, Dec 4, 2007.

  1. davetravis

    davetravis Member

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    I'm trying to understand why the grain and sharpness are variables in any BW film, determined by which developer is used, but constants in color slide films using E6.
    I mean with color slides the grain/sharpness is determined by the characteristics of the film itself(?), since they all use E6, whereby with BW films the resulting grain/sharpness is not determined until after development in a variety of formulas(?).
    My new BW project is giving me a headache!:confused:
     
  2. Michel Hardy-Vallée

    Michel Hardy-Vallée Membership Council Council

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    E6 is a highly standardized process, meaning that there is very little you can tweak. As with all color processes, E6 development works at first like B&W development (reducing silver salts to solid silver). However, the byproducts of that development also react with chemicals in the film to create colour dye spots. At the end of the processing, all the solid silver is bleached away, leaving the dyes only. I'm simplifying a lot, and skipped the reversal step, but you get the idea.

    So think of it that way: in E6, you reduce silver salts (AgX) to solid silver using only one very particular developer, because crucial subsequent steps depend on it. Silver is only an intermediary product. With B&W, solid silver is your final product, so you can make it any way you like.

    E6 restricts variability at the level of AgX -> silver, so the only variable left to control sharpness is the choice of film you make. Think of it that way: if there was only D-76 available for B&W, the only variable left to you for controlling sharpness would be film choice (optics nothwithstanding in both cases, of course).

    Another thing you should bear in mind is that the image properties of dye clouds are not the same as the image properties of silver grains. The latter are opaque, while the other ones are translucent. Light scatter and impression of graininess is different because of that. In fact, an underexposed slide (or an overexposed color neg) will have finer grain than an overexposed one, because thicker layers of dye clouds show less visible impression of grain.
     
    Last edited by a moderator: Dec 4, 2007
  3. srs5694

    srs5694 Member

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    I do mostly agree with Michael; however, it is possible to deviate from standard E-6 formulas. You'll probably get something unsatisfactory, or at least weird. Cross-processing of E-6 film in C-41 chemistry is an example, but you could experiment with the first developer formula in an otherwise standard E-6 process to get positive images in some other way. You shouldn't expect good results, though, at least not if what I've heard is correct; changes that are likely to affect features you're interested in affecting (grain, acutance, etc.) are likely to have undesirable side effects.
     
  4. Michel Hardy-Vallée

    Michel Hardy-Vallée Membership Council Council

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    I agree! You can indeed deviate from E-6, but the result will obviously not be standard. The first developer of E-6 is just a special B&W developer after all, it's not a color dev. I would be curious to know, for example, what happens when first dev is Rodinal, XTOL, or something else...
     
  5. davetravis

    davetravis Member

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    Thanks MHV and SRS for the explanation!:smile:
    I never really tried to understand it before this project, and going forward it will be helpful.
    DT
     
  6. jim appleyard

    jim appleyard Member

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    In b/w, the size of the grains is mostly determined by the manufacturer. When we choose a developer, we can alter it to a degree; Recording Film ( a Kodak high ISO film, no longer made) will always be a grainy film, no matter what dev we use. Ilford's Pan-F is and always will be a fine-grained film.