In nature, structural colors are as abundant as pigments, if not more, Mathias Kolle, a mechanical engineer at MIT, tells me. Optical structures in peacock feathers called photonic crystals cause iridescent color. These feathers are actually pigmented brown—they owe their stunning hues to nanostructure. The shiny, metallic colors of many insects are created by multiple layers of transparent materials organized into complex, reflective patterns. Even the blues and greens of the human iris are structural. The interesting question, Kolle tells me, is whether we can recreate these forms: “Can you make the material structures that nature has grown over millions of years of evolution?”
In the early 1990s, Parker was an art student at the University of Sydney—but spent his time behind a dive mask, admiring resplendent marine life. Come twilight, he would see how the animals colored by pigments would fade, while the iridescent hairs of a lobster, say, were still visible. He wondered how they were doing it.
https://www.smithsonianmag.com/innovation/this-british-zoologist-wants-to-reinvent-color-180981349/