Scientists Find a Color Never Seen Before

Imagine seeing a color that no one who's walked the Earth has ever seen before. That's what US scientists say they've achieved in firing laser pulses into eyeballs, stimulating individual retina cells and creating the impression of a unique blue-green color, more intense than any they've seen, according to a study published Friday in Science Advances. New Scientist describes the hue as "an intense teal." "It was jaw-dropping," Ren Ng, an electrical engineer at the University of California, Berkeley, tells the Guardian. "We predicted from the beginning that it would look like an unprecedented color signal but we didn't know what the brain would do with it."

Humans see color using light-detecting cone cells in the retina. There are three types of cone cells: L-cones, which are sensitive to long wavelengths and red and orange light; S-cones, which are sensitive to short wavelengths and blue and violet light; and M-cones, which are sensitive to medium wavelengths and green and yellow light. Natural light, a blend of multiple wavelengths, stimulates all three cone types. In normal vision, M-cones are only stimulated alongside either L-cones or S-cones, never exclusively, per the BBC. But researchers used a laser to fire a tiny pulse of light to stimulate only M-cones, resulting in a patch of color, beyond the natural range of the eye, appearing in the field of vision.

Five people observed this color, dubbed "olo." The name "comes from the binary 010, indicating that of the L, M and S cones, only the M cones are switched on," per the Guardian. "There is no way to convey that color in an article or on a monitor," Austin Roorda, a Berkeley professor of optometry and vision science, tells the outlet. Researchers did share a swatch of a color, something between turquoise and cyan, which they say is close to olo, but "it absolutely pales by comparison," says Roorda. Though some question the value of the work, researchers say it will help them better understand how the brain creates visual perceptions. Down the road, it might also help people with color blindness, per New Scientist. (More vision stories.)