If there were a color that a person has never seen in their life, what would it look like? Scientists in the United States have succeeded in an experiment to find that answer.
On the 18th (local time), researchers from the University of California, Berkeley, and the University of Washington announced that they succeeded in creating a color that cannot be seen in nature by using a very fine RAY laser aimed at the human eye. The research results were published that day in the international academic journal Science Advances.
A person can see colors thanks to the cells located in the back of the eye's retina. These cells are divided into L, M, and S cells according to the sensitivity to different wavelengths of light. They are activated by long-wavelength red light, medium-wavelength green light, and short-wavelength blue light, respectively. Most colors that a person sees are created when these three types of cells are simultaneously stimulated.
However, in natural light, there is no situation where only the M cells are stimulated on their own. This is why colors created through the M cells cannot be seen. The researchers paid attention to this point and accurately identified the location of the M cells in the human eye, developing a retinal stimulation technique called 'Oz' that stimulates only the M cells with a laser.
Using the Oz technology, the researchers created a color that cannot be seen by ordinary methods, called 'Olo.' It may appear to be a greenish color on the surface, but according to the researchers, it is 'a turquoise color of unprecedented clarity.' It cannot be represented on screens or in pictures and can only be seen through experimental devices.
Five participants in the experiment noted, "It was an incredibly intense color that is hard to describe in words." Ren Ng, a professor at the University of California, said, "I thought something special would come out from the beginning, but the moment I actually saw it, I was truly amazed."
The researchers stated, "This technology could enhance color vision in patients suffering from color blindness, visual impairments, or retinal diseases," adding, "It could also help deepen the understanding of the currently unknown workings of the eye and brain."
However, opinions are divided on whether the discovered color is truly a new color. John Barber, a professor at City, St. George, London University, commented, "While selectively stimulating retinal cells is a technical achievement, there is still an argument regarding the discovery of a new color," stating, "When L cells are stimulated in large amounts, a deep red color can be seen, but brightness can vary depending on the sensitivity of the cells. This is not different from what happened in this study."
References
Science Advances (2025), DOI: https://doi.org/10.1126/sciadv.adu1052