The tiny black dress may be a fashion classic, but making the tiny, perfectly black dress is more a job for scientists. In nature, black can be tremendously functional and fashionable, but for materials engineers, recreating that level of darkness for real-world applications is challenging.

A team of designers, ornithologists, and materials scientists at Cornell University have successfully developed a method to create “ultrablack” fabric, described in a recent Nature Communications paper. The new technique, a two-step process, takes heavy inspiration from the plumage of magnificent riflebirds. Their feathers combine melanin (a pigment) with distinct structures that trap and absorb light.

This dark fabric could eventually end up in cameras, solar panels, and telescopes. For now, though, the team used it to make that classic black dress, finished with a dash of iridescent blue in tribute to the riflebirds that inspired the discovery. The new fabric features an average reflectance of 0.13%, making it the darkest fabric reported so far, according to the paper.

What’s “ultrablack”?

In color theory, “true black” or “true white” are terms often used in graphic design or when describing technology displays. Apple devices also advertise something called “true tone,” which purports to present users with clearer, more accurate colors.

However, “ultrablack” in this context isn’t quite any of these things. Rather, the term is used more as a measure of reflectivity, being defined as a dark shade that reflects less than 0.5% of the light that hits it. Many creatures naturally sport ultrablack in their skin, scales, and feathers, as it grants them mating or survival benefits.

Understandably, scientists have tried to recreate ultrablack in the lab—with limited success. Although one experiment managed to create a tiny tube that reflected as little as 0.005% of visible light, this, like most other attempts, resorted to costly techniques that produced fragile, toxic materials. As the paper notes, these ultrablack materials would be “unsuitable as wearable or everyday textiles that require biocompatibility, breathability, and stretchability.”

Taking lessons from riflebirds

For the new fabric, the researchers collaborated with the Cornell Lab of Ornithology, which presented them with riflebird feathers for analysis. The team then carefully analyzed how the positioning of barbules—tiny, hook-like structures that hold bird feathers together—gave the riflebirds their characteristic plumage.

They found that a strict hierarchy in the feather barbules, combined with melanin-based nanostructures, worked to deflect light inward. As a result, riflebird feathers appear to be extraordinarily black when viewed straight on but look much shinier at an angle.

To replicate these structures, the team first dyed a white merino wool fabric with polydopamine, a synthetic melanin. Then, they took the wool to a plasma chamber and etched it with nanofibrils, or spiky nanoscale structures mimicking the barbules. The final product had an average reflectance of 0.13% and remained ultrablack across wide angles, the study reported.

“The light basically bounces back and forth between the fibrils, instead of reflecting back out—that’s what creates the ultrablack effect,” Hansadi Jayamaha, the study’s lead author and a doctoral student at Cornell’s Department of Human-Centered Design, said in a release.

“From a design perspective, I think it’s exciting because a lot of the ultrablack that exists isn’t really as wearable as ours,” added Larissa Shepherd, study senior author and a material scientist at Cornell. “And it stays ultrablack even from wider angles.”

The team is eager to get this technology out to the market and has already applied for provisional patent protection, Shepherd reported.