Re: [ATM] Can you see a laser beam where it strikes a polishedsurface?

[Vladimir Galogaža <vladimir.galogaza@zg.htnet.hr>]

>Remember that about 4% of the light that impinges on a clean glass surface
>is reflected off of that surface.  As a result, you will indeed see the spot
>of a laser on the glass surface and, when you get to the right angle, 4% of
>that light of the beam will reflect back to your eye.

In addition to above statement:
This 4% will be reflected  in accordance with the reflection law in 
one only direction ( called specular reflection). But this is not what we 
are looking for in polishing quality test. We are looking for a so called 
diffuse reflection. Its direction is not restricted to specular one and
insufficient polishing will be seen from all directions but with intensity
depending on the surface roughness (among other things). 

Vladimir.

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