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Thread: Why my blue-ray pointer beam on paper is blue?

  1. #1
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    Default Why my blue-ray pointer beam on paper is blue?

    I got my blue-ray pointer finally, everything goes well, except one thing. Why it looks blue violet on wall, but only blue on paper? I like my baby so much!!!
    Attached Thumbnails Attached Thumbnails 405nm on wall.jpg  

    405nm on paper.jpg  

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  2. #2
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    It's a phenomenon called fluorescence. Fine paper contains a fluorescent dye to make it look whiter. The dye absorbs light with short wavelengths and emits it at a longer wavelength. Another place you can find a similar dye is in your laundry detergent for white clothes that may contain an "optical whitener".

    If you look around I bet you will find many fluorescent objects, even in nature. As soon as you see the dot change color that means the material is fluorescent. Anything that has a really strong color (neon-like) is likely to be fluorescent.

  3. #3
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    Try shining it at one of those highlighter pens, they glow really well!

  4. #4
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    yeah i was playing with mine last night and was actually laying in bed and shining it and when it hit my shower curtain it looks to be STRONG blue color! i wish it was that color all the time!
    -Josh

  5. #5
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    Just make sure your pointing your projector at a surface that fluoresces, then no one will know its actually a violet, not a blue laser!

  6. #6
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    hahaha must find a giant shower curtain for projections!
    -Josh

  7. #7
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    That would be interesting!

  8. #8
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    even more interesting what sometimes can be behind that curtain.

    J/K

  9. #9
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    hahaha i need to hurry up and buy my fb3 so i can get on this!
    -Josh

  10. #10
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    Quote Originally Posted by tocket View Post
    It's a phenomenon called fluorescence. Fine paper contains a fluorescent dye to make it look whiter. The dye absorbs light with short wavelengths and emits it at a longer wavelength. Another place you can find a similar dye is in your laundry detergent for white clothes that may contain an "optical whitener".

    If you look around I bet you will find many fluorescent objects, even in nature. As soon as you see the dot change color that means the material is fluorescent. Anything that has a really strong color (neon-like) is likely to be fluorescent.
    Thank you, Tocket, how can you know that? I think I can try some other place in the nature. As your said, if I point my pen on the detergent, it will look very very blue?

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