Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 69,764   Posts: 1,516,314   Online: 1039
      
Page 1 of 6 123456 LastLast
Results 1 to 10 of 58
  1. #1

    Join Date
    Aug 2005
    Location
    Earth
    Shooter
    Multi Format
    Posts
    1,560

    Golden Tetras)Cubic Grains and the teradecahedral

    Anybody out there know how to describe a tetradecahedral grain?
    or have a picture handy?

    I can't seem to find one.

    Ray

  2. #2

    Join Date
    Aug 2005
    Location
    Earth
    Shooter
    Multi Format
    Posts
    1,560

    "Golden Tetras" or Cubic Grains and the Tetradecahedral

    Anybody out there know how to describe a tetradecahedral grain?
    or have a picture handy?

    I can't seem to find either.

    Ray

  3. #3
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,880
    Images
    65
    This is the closest I can get. You be the judge.

    OTOH, if it is doable, why don't you make one? Then you can show us the pix.

    PE
    Attached Thumbnails Attached Thumbnails Double run octahedra resized.jpg  

  4. #4

    Join Date
    Oct 2008
    Shooter
    Medium Format
    Posts
    139
    Groobled it.
    Attached Thumbnails Attached Thumbnails tetradecahedron.bmp   tetradecahedron2.bmp  

  5. #5

    Join Date
    Oct 2008
    Shooter
    Medium Format
    Posts
    139
    PE's 14 sided crystals are prettier than mine, though.


  6. #6

    Join Date
    Aug 2005
    Location
    Earth
    Shooter
    Multi Format
    Posts
    1,560
    Quote Originally Posted by Photo Engineer View Post
    This is the closest I can get. You be the judge.

    PE
    Actually, they do look like tetradecahedral grains to me.
    Why are they marked "octahedra"?

    Ray

  7. #7

    Join Date
    Aug 2005
    Location
    Earth
    Shooter
    Multi Format
    Posts
    1,560
    Quote Originally Posted by Ray Rogers View Post
    Actually, they do look like tetradecahedral grains to me.
    Why are they marked "octahedra"?

    Ray
    After thinking about my own question, I think I came up with an answer.
    I will give it a try anyway.

    Octahedral grain can be derived from tetradecahedral grain by continued ripening....

    The grain in your picture were supposed to be octahedra...
    but had there portrait taken before they were completely mature.

    They were "toddlers"!

  8. #8

    Join Date
    Aug 2005
    Location
    Earth
    Shooter
    Multi Format
    Posts
    1,560
    Quote Originally Posted by totalamateur View Post
    PE's 14 sided crystals are prettier than mine, though.

    Thats true.

    In addition, I am not sure they actually have the same structure!
    There seems to be several possible shapes for a tetradecahedron.

    Ray

  9. #9
    Rick A's Avatar
    Join Date
    Mar 2009
    Location
    north central Pa
    Shooter
    Multi Format
    Posts
    5,784
    Images
    31
    Did you try Googleing "photos of a tetradecahedron grain"? I think I saw a drawing of one once but I cant remember where. I think it was a patent for a silver halide grain for photography held by a japanese fellow. Hope that helped.

    Rick

  10. #10
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,880
    Images
    65
    Octahedra = 8 sided, Tetra deca hedra = 4 10 sided. An octahedron in emulsion parlance in the case above is a cube with clipped corners. A cube has 6 faces and 8 corners. If you look closely at my photomicrograph, you see that each side has 6 edges but there are 8 + 6 sides making 14. Go figure!

    There are several possible shapes possible. AFAIK, there is nothing "golden" or special about them.

    PE

Page 1 of 6 123456 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin