Scientists claimed to have discovered a new colour that has not been seen by humans before – but experts aren’t so sure.
It comes after an experiment in which US researchers had laser pulses fired into their eyes.
Researchers say that by stimulating individual cells in the retina that the laser pushed their perception beyond its natural limits.
The five people who are said to have see the new colour describe it as blue-green but they added that it does not fully represent the richness of the experience.
Ren Ng, an electrical engineer at the University of California, Berkeley told the Guardian: ‘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. It was jaw-dropping. It’s incredibly saturated.’
An image of a turquoise square has been shared by the researched to provide a sense of the colour, which they named ‘olo’.
It has been stressed that the hue can only be experienced through laser manipulation of the retina.
Austin Roorda, a vision scientist on the team, said: ‘There is no way to convey that colour in an article or on a monitor. 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.’
Pictured: Austin Roorda, a vision scientist on the team at the University of California, Berkeley
An image of a turquoise square has been shared by the researched to provide a sense of the colour, which they named ‘olo’
However not everyone is convinced as professor John Barbur, a vision expert at City St George’s, London believes the finding has ‘limited value’.
‘It’s not a new colour,’ he said.
‘It’s a more saturated green that can only be produced in a subject with normal red-green chromatic mechanism when the only input comes from M cones.’
Humans perceive colours when light falls on colour-sensitive cells called cones in the retina.
There are three types of cones which are sensitive to long (L), medium (M) and short (S) wavelengths of light.
Natural light is a blend of multiple wavelengths that activates all three cones. Red light tends to stimulates L cones while blue lights trigger S cones. But no natural light stimulates the M cones as it sits in the middle of the retina.
As part of the Berkeley team’s research they they scanned volunteers’ retinas to pinpoint the M cones. Then a laser is used to scan the retina and fires a flash of light into the M cone.
It resulted in a patch of colour in the viewer’s vision – about twice the size of a full moon – that simply doesn’t exist in nature.
The team have dubbed this hyper-saturated green ‘olo’, a nod to binary code, indicating that of the L, M and S cones, only the M cone is ‘on’.
