Researchers at the University of California, Berkeley, claim to have discovered a new colour that is impossible to see under normal conditions. They used a laser to stimulate individual cells in the retina, causing participants to see a shade that goes beyond the natural range of human vision, The Guardian reported.
Image source: Austin Roorda / theguardian.com
The new color is called olo. According to the scientists, it can be described as blue-green, but this does not convey the full intensity and unusualness of the sensations. “We assumed that this would be an unprecedented color signal, but we did not know how the brain interprets it,” said one of the researchers, engineer Ren Ng. “It turned out to be a stunning and incredibly rich shade.”
To get an approximation of olo, the researchers published an image of a turquoise square, but stressed that the true color can only be seen when the laser shines directly on the retina. “It’s impossible to reproduce this color on a monitor, and what we see is only a semblance of the real olo,” explains vision specialist Austin Roorda. They presented a square of this color:
Image source: theguardian.com
The human eye distinguishes colors thanks to three types of cones in the retina, which respond to long (L), medium (M), and short (S) waves of light. In nature, light is always mixed, so the cones are activated simultaneously. However, scientists were able to selectively stimulate only the M cones, which led to the appearance of olo – a color that is impossible to see under normal conditions. Interestingly, the name olo comes from the binary number 010, indicating that of the L, M, and S cones, only the M cones are turned on.
The experiment, published in Science Advances, has sparked controversy among experts. For example, John Barbur, a vision researcher at the University of London, believes that olo is not a new color at all, but simply a more saturated shade of green. In his opinion, the work has “limited value.”
But the Berkeley researchers are confident that their method, called Oz Vision – after Frank Baum’s Emerald City – will help better understand how the brain processes visual information and could be useful in the future for studying color blindness and retinal diseases.
Will regular people be able to see olo? Not yet. “This is fundamental science,” Eng explained. “We won’t be able to reproduce this color on smartphones or TVs anytime soon. Even VR technology can’t do it.” The human brain will only be able to recognize this color in a lab setting, but in the future, this discovery may change the way we see and perceive the world.