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Really unusual question

  1. Jan 14, 2012 #1

    JJ_

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    Hi guys, I make car wax for a living and I want to ask you something about light theory.

    My new car wax is made using natural oils such as hazelnut oil which has a refractive index of 1.468-1.478 estimation.

    My question is this, you see a puddle with petroleum or oil and you see certain colours normally the slower moving light.

    Is there a way I could recreate this by utilising my natural oils to promote some "hues"

    A long shot I know but is this possible ??

    Thanks very much guys!
     
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  3. Jan 14, 2012 #2

    Simon Bridge

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    Yes - you do this by controlling the thickness of the coating.
    Look up "thin films" ... bearing in mind that the car paint absorbs light as well so the colors you can promote will depend on the wavelengths scattered off the paint.

    What happens is, light reflecting off the top of the oil interferes with light reflecting off the water - the interference will be constructive or destructive for a particular wavelength depending on the refractive index of the oil and it's thickness.

    It can be done artificially, for instance, in optical equipment, but I imagine it would be very difficult to do with oils rubbed on a car.
    The surface has to be nanometer smooth.
     
  4. Jan 14, 2012 #3

    JJ_

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    So in essence it has to be a uniform coating ?

    I had thought of a wax using glycerin for the bottom and a harder wax for the top which would possibly create a really small film intereference?
     
  5. Jan 14, 2012 #4

    Simon Bridge

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    You need to avoid small random variations on the surface - ridges, scratches and so on - they tend to average out the interference effects and the bottom layer dominates. A varying thickness surface will favor varying colors - which is why you get different colors off the oil film. The surface has to be smooth.

    You can certainly experiment.
     
  6. Jan 15, 2012 #5

    Andy Resnick

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    Probably not- the thickness has to be tightly controlled and since wax quickly wears off, your hard work will last for a fleeting moment. OTOH, you may be able to mix something into the wax:

    http://www.uspaint.com/paints/color-shifting.asp

    If you haven't seen a car painted with this- it's a really striking effect.
     
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