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Birds of paradise have long been a source of inspiration. The popularity of their shiny, showy feathers for women’s hat plumes nearly drove the whole bird family (Paradisaeidae) to extinction during the 19th century. Under modern legal protections, and thanks to waning interest in fancy hats, birds of paradise are still hanging on. Now, the feathers of one striking species, the magnificent riflebird, have again inspired humans in the realm of fashion, only this time more sustainably.
A new study published in Nature Communications describes the invention of an “ultrablack” fabric that borrowed a page from the riflebird’s plumage playbook. Although quite useful for things like telescopes and solar panels, the color ultrablack, defined as absorbing more than 99.5 percent of the light that hits it—reflecting away less than 0.5 percent—is hard to create. Making synthetic ultrablack materials tends to be expensive and requires the use of toxic substances, such as carbon nanotubes. But the black feathers of the magnificent riflebird (Ptiloris magnificus), native to the rainforests of New Guinea and northern Australia, naturally absorb an astounding 99.95 percent of light. No toxins necessary.
In a feat of biomimicry, engineers in Cornell University’s Department of Human Centered Design created an ultrablack wool that absorbs 99.87 percent of incoming light. First, the researchers dyed regular merino wool with a chemical called polydopamine, a synthetic pigment that mimics the melanin in riflebird feathers. Then, they used plasma to eat away material from the outside of the wool fibers, leaving behind spiky, nanoscale fibrils that matched the feathers’ surface structure—rows of microscopic, tightly bunched barbs. This structure also allowed the synthetic melanin to penetrate deep into the wool.
Read more: “The Reinvention of Black”
“The light basically bounces back and forth between the fibrils, instead of reflecting back out—that’s what creates the ultrablack effect,” explained Cornell Ph.D. student and co-author Hansadi Jayamaha in a statement.
The resulting ultrablack wool is not only the darkest fabric ever created, but also more practical than any ultrablack fabric to date. The researchers washed it in a laundromat, exposed it to bright light, stretched it, and compressed it between steel plates to see if it maintained its ultrablack properties. The material passed with a flying lack of color.
Further, the ultrablackness even proved resilient to modifications of images of the material. Inspired by the beauty of riflebirds, Cornell undergrad fashion design major Zoe Alvarez incorporated the wool into a dress. When the researchers captured images of the dress and then tinkered with contrast, brightness, hue, and vibrance of the photos, all the colors changed … except the ultrablack.
“From a design perspective, I think it’s exciting because a lot of the ultrablack that exists isn’t really as wearable as ours,” said Cornell fiber scientist and co-author Larrisa Shepherd.
From tropical rainforests to Paris runways, ultrablack is the new black. 
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Lead image: kosala000000 / Shutterstock
