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Refraction index of paper?

  1. Aug 17, 2004 #1
    Does anybody here know the refraction index of paper? I couldn't find any info on this... Any kind will do.
  2. jcsd
  3. Aug 17, 2004 #2

    Claude Bile

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    Science Advisor

    I see two difficulties;

    One, white paper does not transmit light in any part of the optical spectrum, so measuring such a refractive index would be rather difficult.

    Two, the composition of the paper, would have a large influence on what the refractive index would be. Even if you managed to find a value, it would only be valid for a particular composition of paper.

  4. Aug 18, 2004 #3
    First, that's not quite correct. A standard sheet of white paper, such as the type used in printers, does in fact transmit visible light, and probably other parts of the spectrum as well. Sure, the light is scattered, but nevertheless it is transmitted. Even if the light is being transmitted through the gaps between the fibers, and the fibers are opaque, even the most opaque materials transmit light for a short distance. Further, what's opaque in one wavelength is not necessarily opaue in another.

    Second, there are other ways to measure the refraction index, which do not require the material to be transparent. FYI, refraction indices have been measured for metals, minerals, etc.

    What could be a problem, is that paper is grainy and usually non-specular. But as I said, any kind of paper would do, and there are kinds where these problems are not as significant, e.g. fine-grained specular paper like the kind sometimes used for photograph prints (although I'm not sure that type is really fine-grained...).
    Ok, but like I said, any kind would do. I only need an estimate, so even if the value is even remotely accurate only for that particlar kind of paper, it will be enough.
  5. Aug 18, 2004 #4
    I think you can find it in handbooks about paper.
    You can try it with google.
    Good luck!!!
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