I understand that light of different wavelengths reflected is what gives off color but what determines which wavelengths, a table, for example, will reflect or absorb? Is it something encoded in the table itself or is it the light that communicates the color?
Why do some things absorb all wavelengths turning them black while others reflect all turning them white?
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Not a chemist, but what I understand is that it comes from a couple of things:
1. It could be the composition of the material itself, ie what molecules it’s made of. The simplest way to think about this might be food coloring. Each of the differently colored food colorings uses certain different chemicals (which each reflect or absorb certain colors of light) to get that color. The same can be said for flavorings as well. Instead of coloring, certain chemicals produce unique flavors due to their structures. For example the banana flavoring that you taste in a lot of candies comes from a chemical called isoamyl acetate. Certain chemicals added to different mixtures give off specific properties, one of those being color.
2. It may also be structural in nature. There are certain insect or birds for example that have structural coloring. The way the microstructure of their shells or feathers is designed creates a way for light to be reflected differently. Imagine if you had (in 2D) a row of triangles (on the hundreds of nanometers scale, similar to the wavelengths of light) lined up next to each other and light was shining in on them from the top left. White light is made up of all color lights which all have different wavelengths corresponding to their energy. As the different colors of light hit those triangles at an angle, only the colors of light with wavelengths corresponding to the spacing of the triangle (say ~500nm or so for green light) will be reflected. All the other colors will be redirected away and won’t be reflected back. This is not a very common way of coloring things, and is mostly found in the natural world on living things.
3. There’s also a few other ways that color can be described such as with different metals giving off different colors (eg silver, gold, copper, etc.) but I don’t know too much about that. I believe it has something to do with the electronic structure of the atom itself, or how many electrons the atom has in its outermost shell. It may also have to do with the crystal lattice structure (how the atoms are connected inside the material) of the material. Might need a materials scientist to better explain that one.
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