[Physics] What about a surface determines its color

opticsphotonsreflectionvisible-light

Light falls on a surface. Some wavelengths get absorbed. The other are reflected. The reflected ones are the colors that we perceive to be of the surface.

What is the property that determines, what wavelengths are reflected and what are absorbed? Is it electronic configuration of the object on which the light falls?

If yes, then if we know the electronic configuration of a surface can we make a model, which will predict the color it will show?

Best Answer

This question is too broad. It involves ALL the objects in the universe which have a surface, i.e., everything. I'm going to avoid giving a lecture here.

In some liquids and most gases the electronic structure of each individual atom or molecule is enough to describe their spectra.

The "property" you are looking for in the case of solids is the band structure. See this page for a good introduction, specially the section about insulators and dopings. People arrived at the point where they needed to describe the spectrum of solids by (macroscopic) parameters instead of the atomic and band transitions (on top of that, sometimes you have to consider relativistic corrections): Absorption, and scattering or fluorescence. See this page for a shorter explanation, note that this is valid not only for visible light. For normal incidence, backward scattering is "reflection", while forward scattering is "transmission". The color you see will also depend on the flatness of the surface, but this does not affect the physics of the light scattering.

One interesting fact is that you could see (actually you can't, this holds for X-rays) that light gets "reflected" to more that one spot because of Bragg's law.

Lastly, according to your OP title, you might consider reading more about gratings, in which the surface is worked to specifically manipulate colors.