[freebeard]

The Ultrabright pigments (Permalink #37) require a thick coating to be effective. Compare this:

phys.org/news/2023-03: Researchers create world's first energy-saving paint—inspired by butterflies

Based on such bio-inspirations, Chanda's research group innovated a plasmonic paint, which utilizes nanoscale structural arrangement of colorless materials—aluminum and aluminum oxide—instead of pigments to create colors.
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Such structural colors are environmentally friendly as they only use metals and oxides, unlike present pigment-based colors that use artificially synthesized molecules.The researchers have combined their structural color flakes with a commercial binder to form long-lasting paints of all colors.

"Normal color fades because pigment loses its ability to absorb photons," Chanda says. "Here, we're not limited by that phenomenon. Once we paint something with structural color, it should stay for centuries."

Additionally, because plasmonic paint reflects the entire infrared spectrum, less heat is absorbed by the paint, resulting in the underneath surface staying 25 to 30 degrees Fahrenheit cooler than it would if it were covered with standard commercial paint, the researcher says.

"Over 10% of total electricity in the U.S. goes toward air conditioner usage," Chanda says. "The temperature difference plasmonic paint promises would lead to significant energy savings. Using less electricity for cooling would also cut down carbon dioxide emissions, lessening global warming."

Plasmonic paint is also extremely lightweight, the researcher says.

This is due to the paint's large area-to-thickness ratio, with full coloration achieved at a paint thickness of only 150 nanometers, making it the lightest paint in the world, Chanda says.