Light passing through rough surface Why does polishing rough surface make it glossy? Like as the rough surface of an epoxy-made cube. When the surface of that cube is scratched against rough surfaces it also gets rough but polishing carefully and methodically makes it like glass. What's the mechanism of light passing through the surface?
 A: A matte appearance of a transparent (and pretty similarly reflecting) surface means there a microscopic irregularities in the surface, each of which acts like prisms or lenses. Since these irregularities refract (or reflect) light in random directions, you cannot see what is behind the matte object (or behind you, in case of reflection). It is like the pixels of the image had been scrambled in a blender.
If the surface irregularities are not very deep, the deflections by them is not very strong, so that you might still be able to make out the outlines of what is behind.
By polishing, you reduce the depth of the irregularities, because the particles in the polish are very small and grind off the sharpest spikes in the surface, leaving only rather "long-waved" bumps. The polish also might introduce new scratches, but this will not contribute to the dullness of the surface if they are close to or below the wavelength of light (because, generally, light does not notice any obstacle that is smaller than its wavelength on its way from A to B).
A good analogy for polishing is watching an object under a water surface. As long as the water surface is troubled, you can hardly recognize the object, but if the water is given the chance to calm down, you will soon recognize the object again.
