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Black usually sounds simple, until you try to make the blackest black.
Scientists call it ultrablack: a colour that reflects less than 0.5% of incoming light. It is prized for cameras, telescopes, and solar panels—and notoriously hard to make. Worse, many ultrablack materials lose their darkness when viewed from an angle.

Now, a team at Cornell University has cracked the problem - with help from a bird.

Inspired by the magnificent riflebird, whose feathers appear impossibly black, researchers at Cornell’s Responsive Apparel Design (RAD) Lab have created the darkest fabric ever reported. And unlike previous ultrablack materials, this one is wearable, scalable, angle-independent—and made from wool.

Nature, it turns out, has been doing ultrablack better than humans for millennia.

The riflebird’s feathers don’t rely on pigment alone. Their secret lies in microscopic structures - tightly packed barbules that trap light and force it to bounce inward until almost none escapes. The Cornell team decided to copy that trick.

Their process is surprisingly simple and elegant. First, they dyed white merino wool using polydopamine, a synthetic version of melanin, the same pigment found in birds, fish, and butterflies. Then they placed the fabric in a plasma chamber, where controlled etching created nanofibrils - tiny spiky structures that mimic the riflebird’s feather architecture.

The result? Light enters the fabric and gets lost.

Instead of reflecting outward, light ricochets between the nanofibrils until it is almost entirely absorbed. “That’s what creates the ultrablack effect,” explains doctoral researcher Hansadi Jayamaha.

The numbers are striking. The fabric achieved an average reflectance of just 0.13%, making it the darkest textile ever reported. Even more impressive, it stays ultrablack across a 120-degree viewing range, remaining visually unchanged from sharp angles where other materials turn shiny or grey.

For designers, this changes everything.

“Most ultrablack materials aren’t wearable,” says Larissa Shepherd, assistant professor and director of the RAD Lab. “Ours is. And it stays ultrablack even from wider angles.” The research, published on November 26 in Nature Communications, positions ultrablack not just as a lab curiosity, but as a functional textile.

The implications go far beyond fashion. According to researcher Kyuin Park, the fabric could be used in solar thermal applications, helping absorb and convert light into heat. Potential uses include thermo-regulating camouflage, advanced protective gear, and performance apparel.

Still, fashion provided the ultimate proof. A dress designed by Zoe Alvarez ’25, inspired by the riflebird, used the ultrablack fabric alongside iridescent blue. When image contrast and brightness were altered, every colour shifted - except the ultrablack. It stayed black. Perfectly.

Cornell has filed for provisional patent protection and is exploring commercialisation through its Ignite Innovation Acceleration program.

From feathers to fibres, ultrablack has finally found a fabric-friendly future and it might just redefine what “black” really means.