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.
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 ?
Mustafa Umut Sarac