Bright Light vs White Light

  1. What difference does our eyes detect when we see light, that our brain can differentiate between simply a whiteboard and the sun being reflected on a whiteboard? A whiteboard under normal circumstances looks white, yet when a bright light source is reflected on it, we notice it is not the same. It is a bright white whiteboard.
     
  2. jcsd
  3. tiny-tim

    tiny-tim 26,053
    Science Advisor
    Homework Helper

    welcome to pf!

    hi cjduncana! welcome to pf! :smile:
    there is a wide range of colours that we call "white"

    direct sunlight is slightly more yellow than a whiteboard, so the whiteboard looks sunnier

    you see the same effect in a garden when the sun comes out from behind a cloud … suddenly everything looks slightly yellower

    if an artist paints an outdoor scene with sunlight falling on the canvas, the painting will look dull when viewed in ordinary light … but if he paints with the canvas in shadow, he will get the colours right

    (art galleries in the northern hemisphere usually have windows that let in north light, since that is the nearest to "natural white")
     
    Last edited: Mar 22, 2013
  4. Evo

    Staff: Mentor

    Do you mean illumination?
     
  5. Drakkith

    Staff: Mentor

    Color perception is a complicated subject. Not only do you have spectral colors, IE those from light of a single wavelength, you also have non-spectral colors, which are caused by mixing various wavelengths together. On top of that you have to worry about luminance and shading, which can alter the perceived color. And to make it even more complicated, your brain can see the color of one object differently depending the color of objects that surround it!

    http://en.wikipedia.org/wiki/Color_constancy
    http://en.wikipedia.org/wiki/Color_vision
    http://en.wikipedia.org/wiki/Chromatic_adaptation
     
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