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Thread: Gray 3 and Q factors

  1. #1
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    Wave Gray 3 and Q factors

    I recieved an email from a optometrist ask these questions below, I not sure what is ment by the second question, maybe you have some thoughts or idea as to what is being asked. If know the answer to these questions your input would be appreciated.
    Reagrds
    Youngerman

    Hoping you can help again;
    Grey
    Grey 3

    Grey 3 - how is different from a normal grey, and was there ever a Grey 2

    One more question If I may:
    I understand deeper colours are more likely to fall foul of the traffic signal detection requirements,ie Q factors. I believe dark brown lenses, in particular are a problem and at 15% transmittance many brown lenses would fail.
    Is it true that polaroid browns in sunglasses were OK, but no longer available


    I wonder historically has the term Polaroid always referred to polarising (ie has a company Polaroid ever existed and or has the brand Polaroid been produced with coloured lenses that were not polarised)

    How do we measure for Q factors-most instruments I know of measure UV absorption and visible transmittance etc

    Peter

  2. #2
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    Quote Originally Posted by Youngerman View Post
    I recieved an email from a optometrist ask these questions below, I not sure what is ment by the second question, maybe you have some thoughts or idea as to what is being asked. If know the answer to these questions your input would be appreciated.
    Reagrds
    Youngerman

    Hoping you can help again;
    Grey
    Grey 3

    Grey 3 - how is different from a normal grey, and was there ever a Grey 2

    One more question If I may:
    I understand deeper colours are more likely to fall foul of the traffic signal detection requirements,ie Q factors. I believe dark brown lenses, in particular are a problem and at 15% transmittance many brown lenses would fail.
    Is it true that polaroid browns in sunglasses were OK, but no longer available


    I wonder historically has the term Polaroid always referred to polarising (ie has a company Polaroid ever existed and or has the brand Polaroid been produced with coloured lenses that were not polarised)

    How do we measure for Q factors-most instruments I know of measure UV absorption and visible transmittance etc

    Peter
    To try to answer these questions:

    Grey and Grey3 are generic names for colors, and have not been specifically defined. Grey1 lenses are typically lighter than Grey3 lenses, and Grey 2 would be somewhere between them, but they are mostly qualitative descriptions. Grey3 is often used synonymously with Grey or Gray.

    Q factors are used in some sunglass standards (European, Australian) to define minimum transmission of light in certain color regions for traffic signal detection, corrected for lighting and human vision. If the lenses are extremely dark, or if the lenses cut out significant regions of the visible spectra, one can have problems seeing the signals. MANY brown lenses pass these tests easily. However, other lenses – and not just brown - may have a severe spectral cut-off that can interfere with color viewing. Therefore, it is important to test any lens to see if it passes the Q factor tests. The sunglass standards give all the details on how to calculate Q factors from spectral data. Standards documents are available for sale from the standards groups (such as ISO).

    Edwin Land was the founder of Polaroid Corporation, and the inventor of the synthetic polarizers used in lenses today. (although they are quite different than his originals). I believe the only lenses made by Polaroid Corporation were polarized, and the original were sold to American Optical. Polaroid still is a brand, and is licensed by various companies for various uses including lenses.

    Hope this helps.
    Dave

  3. #3
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    thank you CEO

    Thank You David (CEO) for your reply, I will pass the information on.

    "Remember, Younger Optics the easiest company to deal with"

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