Particle Size Distribution of Emulsion

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by Kirk Keyes, May 4, 2009.

  1. Kirk Keyes

    Kirk Keyes Member

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    Greetings all -

    I've uploaded a particle size analysis of an emulsion that I half completed last Januart to my website. You can find the page to download the pdf of the report here:
    http://www.keyesphoto.com/KDKtech-Emulsion_Making-Emulsion_2009-01_Particle_Size_Distribution.html

    The units are in um.
    As far as the meaning, I'm not sure at this point. A lot of particles in the 0. to 1.5 um range though.

    Keep in mind I only made it to the washing stage, and that emulsion was not cooked with sulfur for speed.

    There's some nice micrographs of the crystals too. It was intended that this would be a tabular grained emulsion.

    Kirk
     
  2. Photo Engineer

    Photo Engineer Subscriber

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    Is this the SRAD you mentioned earlier? If so, it would most likely not be a t-grain emulsion. To get a good t-grain, you need a double run to maintain the vAg at the proper value.

    The resolution you show is typical of lower resolution micrographs. They are very good for analysis of lots of grains. The size analysis is usually plotted as size vs frequency on the y/x axes. This usually yields a somewhat bell shaped curve. I have difficulty interpreting your data having used the other method for years. Sorry. I guess it is an old age thing. :smile:

    PE
     
  3. Kirk Keyes

    Kirk Keyes Member

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    It was a double run, with a high bromide concentration.

    I had no control on how the graphs were made, it's a function of the software that was used. It's certainly not ideal for emulsion making, as it was designed more for particle counting in lubrication oils and such.
     
  4. Photo Engineer

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    It is pretty hard to see then if it is a T-grain. I suspect that it is not. The crystals look too rounded.

    PE
     
  5. Kirk Keyes

    Kirk Keyes Member

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    I agree they do generally look rounded... A few do look triangular or truncated triangular, and there are some large tablets here and there, but mostly they are rounded.

    Well, it is a first try.

    I need to get the VAg electrode design going! I have my silver wire, I've got some tubing - I need to get some KNO3.

    And it's too bad that AgX crystals are right on the border of optical microscope resolution... 10 times bigger would have been nice.
     
  6. Photo Engineer

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    Kirk;

    I ran the calculation and you will need about 0.01 M/L of NaBr at 40 deg C to make a pAg of 9.56 which is nominally what you would need for making a T-Grain. That is a generalization.

    PE
     
  7. Kirk Keyes

    Kirk Keyes Member

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    If I read my notes correctly, I had about 2.2 mol/L Br in solution!
     
  8. Photo Engineer

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    By my calculation, that would be a pAg of about 11 or 12 at 40 deg C. That sounds like a good way to make rubble. :wink:

    PE
     
  9. Kirk Keyes

    Kirk Keyes Member

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    I little high, huh? Not sure what I was thinking. Nonetheless, they are not too bad looking (at least in the photos!)