Scientists claim to have found colour no one has seen before

Summary

After walking the Earth for a few hundred thousand years, humans might think they have seen it all. But not according to a team of scientists who claim to have experienced a colour no one has seen before.The bold – and contested – assertion follows an experiment in which researchers in the US had laser pulses fired into their eyes. By stimulating individual cells in the retina, the laser pushed their perception beyond its natural limits, they say.Their description of the colour is not too arresting – the five people who have seen it call it blue-green – but that, they say, does not fully capture the richness of the experience.“We predicted from the beginning that it would look like an unprecedented colour signal 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. It’s incredibly saturated.”The researchers shared an image of a turquoise square to give a sense of the colour, which they named olo, but stressed that the hue could only be experienced through laser manipulation of the retina.The researchers claimed this square was the closest colour match they had to olo.“There is no way to convey that colour in an article or on a monitor,” said Austin Roorda, a vision scientist on the team. “The whole point is that this is not the colour we see, it’s just not. The colour we see is a version of it, but it absolutely pales by comparison with the experience of olo.”Humans perceive the colours of the world when light falls on colour-sensitive cells called cones in the retina. There are three types of cones that are sensitive to long (L), medium (M) and short (S) wavelengths of light.Natural light is a blend of multiple wavelengths that stimulate L, M and S cones to different extents. The variations are perceived as different colours. Red light primarily stimulates L cones, while blue light chiefly activates S cones. But M cones sit in the middle and there is no natural light...