Pigments absorb particular bandwidths of light depending on their chemical composition; whatever is not absorbed is reflected, and it is this reflected light that determines the colour we perceive. Structural colour isn’t chemical: Instead, tiny structures, often smaller than a single wavelength of light, redirect and slow light waves down, causing them to interfere with each other in ways that depend on the shape, size, and spacing of the scattering structures, as well as on the angle of the incoming light and the position of the observer.
