2 Lead oxide color in Leitz glass

Discussion in 'Camera Building, Repairs & Modification' started by Mustafa Umut Sarac, Feb 8, 2009.

  1. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    I discovered that there are two different colors lead oxides at science.
    One is blue , one is red.
    And I looked to the Leitz Noctilux patent and the lens made % 95 , lead oxide glass.
    When I looked the colors of pictures shift to blue and van gogh yellow at the extreme low light.
    When I looked to the Summitar , its 2.8 and blue heavy lens but it creates wild oranges at limelight.
    When I looked to Elmar , its 3.5 , no blue cast but able to very strong reds , greens and gold colors.
    Result :
    More dim light lens have more blue glass with lead exide 1.
    Darker the lens , more red lead oxide goes in to the glass formula.
    Is it correct ? What do you think ?

    Best ,

    Mustafa Umut Sarac

    Istanbul
     
  2. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    I learned newly that there is also yellow lead oxide at the market.
     
  3. Ole

    Ole Moderator Staff Member Moderator

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    It isn't quite that simple.

    Yellow lead oxide is Pb(II)O, which can also be red. The difference is in the crystal structure. There is no crystal structure in glass, so it's colourless there.

    Red lead oxide is either the aforementioned red Pb(II)O, or Pb3O4 which is really Pb(II)2Pb(IV)O4. It's used as a red pigment and in lead glass. Again its colour is dependent on structure, so that it's colourless in glass.

    "Blue" lead oxide isn't blue, it's black. Pb(IV)O2 is used in lead/acid batteries. It's a strong oxidant, so it would be reduced to Pb(II) in contact with a gas flame which is what's used in glass smelting. For that reason it isn't used in glass making - it's both cheaper and safer to use the Pb3O4 version, since the end result is identical.
     
  4. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Thank you Ole
     
  5. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    How Schott or other engineers engineer the color transmittance values ?
    Do you know that ?