Scientists Reveal “Olo”: A Groundbreaking Color Never Seen by Human Eyes

In a stunning breakthrough, a group of scientists in the United States claim to have discovered a brand new color — one that no human has ever seen before. The color, named “olo,” was observed during an innovative experiment involving laser pulses directed into participants’ eyes, targeting specific cells within the retina.

The findings, published in Science Advances, were led by researchers from UC Berkeley and the University of Washington. One of the study's co-authors, Professor Ren Ng of the University of California, described the discovery as “remarkable” and suggested it may pave the way for future research, especially in the field of color blindness.

The experiment was conducted using a custom device called “Oz,” composed of lasers, mirrors, and optical instruments. This device was engineered to precisely stimulate M cone cells in the retina without activating the neighboring L (long-wave, red) and S (short-wave, blue) cones, which typically overlap in natural vision, making the color olo uniquely isolated.

The human retina contains three types of cone cells — S, M, and L — each tuned to detect different wavelengths of light (blue, green, and red). Normally, colors we perceive are the result of combinations of these cones being stimulated together. But in this study, researchers managed to activate only the M cones, creating a visual signal never encountered in the natural world.

During the experiment, five participants — including Professor Ng — took part, with all individuals possessing normal color vision. Each participant had a laser beam shone into the pupil of one eye, with the resulting color perception being unlike anything they had experienced before. Three of these participants also co-authored the paper.

Professor Ng likened the experience to discovering a more intense version of a familiar shade. “Imagine you’ve only seen pastel pink your whole life,” he said during an interview on BBC Radio 4’s Today programme. “Then one day, someone wears a shirt that’s so intense, you call it a new color — and we name it red. That’s what olo felt like.”

To ensure consistency, participants were asked to match the new color using a controllable dial, confirming that each saw a similar hue. They described olo as a deeply saturated blue-green shade, one that doesn’t exist in the visible spectrum under ordinary conditions. This is because natural light always stimulates more than one type of cone, making the isolation of olo impossible without artificial assistance.

Despite the enthusiasm from the researchers, not everyone in the scientific community agrees on the implications. Professor John Barbur, a vision specialist at City St George’s, University of London, praised the technical achievement but called the claim of discovering a “new color” debatable. He emphasized that changes in cone stimulation can alter perceived brightness and hue, which doesn’t necessarily indicate a new color outside the known spectrum.

Still, the researchers remain hopeful about the future applications of their work. Professor Ng acknowledged the complexity of replicating olo and its inaccessibility in natural vision. However, he expressed optimism that this discovery might one day help people with color vision deficiencies see a broader spectrum of colors, providing new tools and insights into how we perceive the world.