US researchers claim to have discovered a new colour: "Olo"

A team of researchers from the United States claim to have discovered a new colour, naturally invisible to the human eye, which they have named "olo", reports the BBC. The discovery was published in the journal Science Advances and could open new perspectives in understanding visual perception and treatments for colour blindness. The colour was perceived by participants in an advanced optical experiment, in which laser pulses were directed into the retina to selectively stimulate a single type of cone cell, responsible for perceiving the colour green (M cells). According to the research team, this isolated stimulation generates a visual signal "impossible" in natural conditions, which led to the perception of an extremely saturated blue-green hue, unlike any previously known colour.

• High-precision optical experiment

The study was led by Professor Ren Ng, from the University of California, Berkeley, who was also one of five participants in the experiment. The participants, all with normal color vision, looked into a device called Oz, which combines lasers, mirrors and sophisticated optical components. The device was specially designed to stimulate only one type of photoreceptor cell, without activating the others - a remarkable technological feat in itself. "Olo is more saturated than any color you can see in the real world," Professor Ng explained in an interview with BBC Radio 4. "It's like you've only seen pale shades of pink your whole life, and one day a shirt appears in such an intense pink that it looks like a completely new color," he metaphorically illustrated.

• Dispute among specialists

While the discovery is considered remarkable from a technological point of view, some experts question whether a new color actually exists. Prof. John Barbur, a vision researcher at the University of London who was not involved in the study, said that the perception of a new color may be a matter of neurological interpretation, rather than evidence of a new type of visual stimulus. "Modifying the intensity of perception by stimulating cones is not a completely new phenomenon," he explained. "It is possible that olo is just an extreme intensification of an already known visual sensation."

• Implications for color blindness

Despite the controversy, the researchers hope that the results could contribute to a better understanding of atypical visual perception and the development of innovative treatments for people with color vision deficiencies. Professor Ng acknowledges that olo is "very difficult to reproduce" in natural conditions, but promises that research will continue.