Silver Grain Size and If 1 to 100 nanometers ,why we dont see plasmon color ?

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by Mustafa Umut Sarac, Nov 23, 2012.

  1. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    What is the minimum grain size in BW Film Emulsions ? If they are smaller than 100 nanometers , why we dont see them in color from plasmonic effect ?

    Umut
     
  2. Lukas_87

    Lukas_87 Member

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    I suppose you need to make a grid (or some other kind of a repeating pattern) of particles to see such effects. In film the grains are randomly positioned. if your plasmonic effects aren't a kind of interference image then I'm mistaken.
     
  3. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Lukas,

    You are correct at your guess, its not related to interference but the resonation of electrons at nanopowder size particles and release a new color.

    Umut
     
  4. BobCrowley

    BobCrowley Subscriber

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    I think we do. The size and distribution of particles produce Carey Lea silver which is yellow to red for instance. It is necessary to have effects that are specific to some portion of the visible spectrum to see a color, and most collections of particles have a wide size distribution, but not all. Aperiodic location aids visualization of the so-called plasmonic effect. Periodic order produces diffraction patterns that are independent (mainly) of particle size. Resonance (like quantum dots) and Mie scattering both contribute to color but are different in principle.

    http://microphonium.blogspot.com/2011/11/press-release-about-my-work-and-patents.html
     
  5. dwross

    dwross Subscriber

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    Hi,

    Could you guys refresh the memory on what this discussion is all about. Some wonderful photographic miracle, I expect, but in all truth, the significance is lost on me. Holography?? Color screens?? (I plead groggy stupidity from too much holiday cheer:smile:.)
    d
     
  6. Vaughn

    Vaughn Subscriber

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    Too much sipping, Denise? :wink:
     
  7. dwross

    dwross Subscriber

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    :laugh: (Inside joke: I recently asked Vaughn to send me his sipping costs on a box of photo goodies he put together for TLF. He suggested a payment in Scotch! But, yes, too much sipping and eating, starting Friday with the best Solstice party ever. Carrots and water for me for a couple of days!)

    Hope everyone had a great time,
    d
     
  8. BobCrowley

    BobCrowley Subscriber

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    With the decline and expected demise of color emulsions, there is a renewed interest in known chromophores and materials that are like dyes and are being used in the so-called nanotech sector, today. I work in that field and Umut has found several interesting articles and papers about photonic effects of nanoparticles, for instance. Reading through these, it is exciting to see today's researchers refer to such things as silver halides. (even though they sometimes act like they discovered them).

    Our group and others are working or seriously studying new and alternative color processes. For instance, we have a direct positive monochrome process that we think could also be used for color. It is very unlike anything produced before and uses nanotech techniques. A lot happens at the photonic scale where sizes of things such as thin films and particles are in the order of 200nm to about 2000nm in size.

    It is all about making film for film cameras, such as 4x5 cameras.
     
  9. dwross

    dwross Subscriber

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    Very cool. Good luck!
     
  10. Bob Carnie

    Bob Carnie Subscriber

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    Hi Bob

    I would be very interested in hearing about your process for colour.

    Bob