What’s the difference between pigments and light scattering structures?

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I saw a similar question being asked here but I understood absolutely none of the responses so I’m gonna ask for myself.

I often hear people saying that only brown and orange pigments exist, and all other colors are caused by light bouncing/scattering off certain microscopic structures and then hitting our eyes.

What I don’t understand is how brown and orange can exist without being scattered light??

Like- “brown animals are brown because they have brown pigments, blue animals are blue because that’s the color their coat bounces back at you”

WHAT’S THE DIFFERENCE.

I’m sorry if I’m not explaining myself well.

In: Physics

3 Answers

Anonymous 0 Comments

Art and science have almost opposite definition of light and color

In science; a white light source contains all the different color wavelengths which we can separate with a prism

In art; a white paint or dye is unable to absorb and wavelength and bounces/reflects light back to you as white

In art; red is the act of absorbing all wavelengths except red……

So by being red; it’s actually configured to reject red

Anonymous 0 Comments

> pigments and light scattering structures

Different physical processes are at work here.

Pigments *absorb* certain colors/wavelengths (converting that part of the spectrum to heat) and reflect other parts. Thus a green pigment, for example, will absorb blue and red light and appear, well, green. The same goes for dyes, as in a glass of red wine.

But some colorless substances can also filter out colors if they are given a *regular* microscopic structure, roughly of the size of light wavelengths. The simplest example is a CD, where you can see rainbow colors albeit the object itself is just colorless metal on a plastic support. This is caused by its regularly spaced grooves, which happen to be of the right size. (See the [Diffraction grating](https://en.wikipedia.org/wiki/Diffraction_grating) Wiki page for the physics.)

This also exists in nature, on some beetles, butterflies (their scales sporting these grooves) or birds. The main difference is that using the second method ensures “sharp” filtering, i. e. vivid colors, while natural pigments (first method) tend to have rather broad absorption and will often look muddy/brownish.

Anonymous 0 Comments

If you grind up a pigment, you end up with a powdered pigment the same colour as you started with because the colour comes from how light interacts with the electrons within the atoms. This can then be used in dyes and paints.

If you grind up a light scattering structure, you end up with a grey powder because the colour comes from how the light interacts with the arrangement of the atoms, which you’ve now destroyed.