What is ‘olo’? Scientists say they’ve discovered a new color never seen before

LOS ANGELES - A group of researchers believes they’ve discovered something no human has ever seen before—a color. 

Known as "olo," the hue emerged during a highly controlled laser experiment and has been described by participants as a strikingly saturated teal, beyond anything found in the natural world or digital displays.

A color outside the rainbow

The backstory:

The study, published last week in Science Advances, involved stimulating just one type of cone cell in the human retina using a device known as Oz, which emits precise laser pulses. Under natural lighting, stimulating one cone type usually activates others due to overlapping sensitivities. 

But by isolating only the M (medium-wavelength) cone, which normally helps humans perceive green, researchers triggered a color experience that the brain doesn’t normally process.

"It was jaw-dropping. It’s incredibly saturated," said co-author Ren Ng, an electrical engineer at the University of California, Berkeley, who was also one of the five people to see olo. "We predicted it would look like an unprecedented color signal, but we didn’t know what the brain would do with it," he told the Guardian.

How they saw olo

First, the researchers mapped out each participant’s retina to identify the location of cone cells. They then targeted M cones with laser pulses and asked the participants to describe what they saw. Each of them independently selected teal as the closest match—but then had to desaturate it by adding white light in order to match the intensity of what they had seen.

In short, olo is not just a teal. It’s a teal beyond teal—more saturated than any display or pigment can replicate.

What they're saying:

Not all vision experts are convinced that olo qualifies as a truly "new" color in the way that red, blue, or green are. Some suggest it’s just a rare stimulation of color perception that existing theories can already explain.

Still, the technical achievement is being widely recognized.

A digital approximation of "olo," the new teal-like hue that scientists say was seen by only five people through a laser-based vision experiment. (Credit: Science Advances / © 2024 American Association for the Advancement of Science (AAAS) )

"It’s a fascinating study, a truly groundbreaking advance in the ability to understand the photoreceptor mechanisms underlying color vision," said Manuel Spitschan, a vision scientist at the Max Planck Institute for Biological Cybernetics, in an interview with Scientific American.

Others believe the findings could help develop better treatments for color blindness, particularly in people with red-green deficiencies, by showing how selective stimulation might expand their range of perception.

Why you won’t see olo on your phone

Big picture view:

The catch? For now, seeing olo requires a laser lab setup and technology far beyond anything used in televisions, smartphones, or VR headsets. That hasn’t stopped people from wondering whether this discovery could one day lead to richer visual experiences or even a fourth "primary" color for future screens.

"This is basic science," Ng told the Guardian. "We’re not going to see olo on any smartphone displays or any TVs any time soon."