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Name: Joshua T.
Status: other
Age: 30s
Location: N/A
Country: N/A
Date: 4/9/2003

Hello. I hope I am not wasting your time on this question, but I cannot seem to locate an answer. I believe I once read, in reference to how light is reflected off of glass, and dependant on the 'brightness' or 'darkness' on the other side, that the amount of reflection happens in 8% increments. i.e. 8% is reflected, then 16%, but not a number in between. Did I imagine reading this? If not, was it explaining something else and I misunderstood? Thanks a 1,000,000 for your help!


You are probably referring to the reflection of an air/glass interface. The precise amount of light reflected at an air to glass interface depends on the index of refraction of the glass but for "normal" glass it is about 4%. There is an air to glass interface on both sides of a piece of glass. 4% of the light entering the glass is reflected and 96% transmitted. When it reaches the glass to air interface an additional 4% of the 96% is reflected. Thus, of the light shining into a window about 8% gets reflected back to the source side of the glass.

Hope this helps.

Greg Bradburn

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