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View Full Version : Shading difference between light and dark

John Keates
03-05-2005, 12:33 AM
Hi there,

I hope this isn't off topic but I suspect that people here know the answere to the following:

What is the difference between the appearence of light and dark surfaces when they are adjusted to have the same average brighness?

I remember reading that studies were done where two (nearly) identical rooms were made each only veiwable through a little hole. The difference between them was that one was painted white and the other black (or dark). They were lit with a single light that was set to a brightness which made the amount of light coming out of each of the eye holes the same.

When people looked through the holes, they were able to see which one was white and which one was black. How oculd they do this? I understand that it is something to do with the way that light is reflected but how exactly?

Sorry if this is a silly question but it has been bothering me for ages.
jeremybirn
03-05-2005, 12:58 AM
In the dark paint, the light will be dampened down much more quickly by the 2nd bounce and beyond, so the shading basically has less GI irradiance in it, with fewer noticeable bounces. If both paint colors were equally glossy, then you'd also see much more of a highlight on the brightly lit dark color paint, than on the dimly lit, light color paint.

-jeremy
John Keates
03-05-2005, 06:58 PM
Thanks Jeremy! That is pretty much what I was thinking. It is good to have someone confirm it. I hadn't thought about the specular part iether - makes sense.
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