A groundbreaking discovery by a team of scientists has led to the identification of a “new” color that the human eye cannot naturally perceive. Dubbed “olo,” this mysterious hue can only be seen with the help of specialized technology. The discovery opens up new possibilities for understanding how we perceive colour and how advanced technology can help us see beyond our natural limitations. The discovery of Olo Scientists at the University of California, Berkeley, and the University of Washington School of Medicine unveiled their finding in a study published in Science Advances on April 18. They introduced a new technique, named “Oz,” after the Wizard of Oz, which uses laser pulses to “trick” the human eye into perceiving olo, a colour beyond the range of normal human vision. Although olo can’t be seen with the naked eye, the few who have experienced it describe it as a color reminiscent of teal, yet more vibrant and saturated than any teal seen before. How do humans perceive color The human eye detects color through three types of photoreceptor cells in the retina: S cones, which pick up blue wavelengths; M cones, sensitive to green; and L cones, which detect red wavelengths. Together, these cones help the brain interpret the colours we see. But what happens when you isolate one type of cone, as was done with olo? How scientists found Olo To discover olo, scientists targeted the M cones, which typically overlap with S and L cones. By stimulating these M cones in isolation, they were able to create a colour that had never been experienced before. Ren Ng, a professor at UC Berkeley, wondered what would happen if the M cones could be stimulated without interference from the other cones. He and his colleague Austin Roorda developed the Oz technology to achieve this, using a highly precise laser to target individual photoreceptors. The research began in 2018 and was led by James Carl Fong, a doctoral student. Through their work, they were able to induce human participants to see olo, a colour that has always existed, but remained hidden from our natural vision. Is Olo really a new colour While olo is a completely new experience for those who see it, the colour itself isn’t new in a physical sense. It’s simply a shade that falls outside the visible spectrum of the human eye. As Francis Windram, a research associate at Imperial College London, explains, the discovery of olo is a matter of making an invisible shade perceptible with technology. Whether olo is truly new is a question of perspective: from a scientific standpoint, it exists, but it only becomes real when we can name and describe it. Who has seen Olo Five people—four men and one woman have experienced olo so far. All were selected for having normal colour vision, and among them were co-authors of the study, including Ng and Roorda. Two other participants were unaware of the study’s goal when they first took part. What does Olo look like Those who have seen olo describe it as a teal or green-blue colour, but unlike any teal they’ve encountered. Roorda, one of the study’s authors, described it as “the most saturated natural colour” they had ever seen, adding that the standard version of teal now appeared pale in comparison.
