Researchers in the US have made a groundbreaking discovery that challenges human understanding of colour perception. By using laser pulses to stimulate individual cells in the retina, they claim to have seen a new colour, dubbed “olo”, which is blue-green in appearance but unlike anything experienced by humans before.
The team used an experiment involving five people, who had laser pulses fired into their eyes while mapping the positions of their colour-sensitive cells. The result was a patch of colour approximately twice the size of a full moon that exceeded the natural range of human vision.
“We predicted this outcome, but we didn’t know what the brain would do with it,” said Ren Ng, an electrical engineer at the University of California, Berkeley. “It was jaw-dropping. The colour is incredibly saturated.”
However, experts have expressed skepticism about the claim. John Barbur, a vision scientist at City St George’s, University of London, described olo as a more saturated green that can only be produced by stimulation of M cones. He questioned the tool’s value, stating it had “limited value”.
Despite this, the researchers believe their discovery has potential in basic science questions about visual perception and may lead to advancements in understanding colour blindness or diseases affecting vision like retinitis pigmentosa.
Ng noted that olo cannot be experienced on current smartphone displays, TVs, or VR headset technology.
Source: https://www.theguardian.com/science/2025/apr/18/scientists-claim-to-have-found-colour-no-one-has-seen-before