Black Mirror, eat your heart out. Researchers have apparently just figured out how to make people see a color completely new to humanity.
Scientists at the University of California, Berkeley conducted the research, published Friday in Science Advances. Using a technique called Oz, the research team induced human volunteers into seeing a color beyond the “natural human gamut.” Oz could allow scientists to conduct experiments previously not possible before, the authors say, and the lessons we learn from it might even someday help color-blind people regain their missing color vision.
Our retinas contain certain photoreceptive cells, known as cones, that allow us to see color. There are three cone types that correspond to different wavelengths of light: short-wavelength (S) cones, medium-wavelength (M) cones, and long-wavelength (L) cones.
Typically, when we try to reproduce color in front of someone’s eyes, we do so by manipulating the spectrum of light seen by the retina’s cones. But since some of our cones, particularly M cones, share overlap in how they respond to certain wavelengths, there are theoretically colors out there that our eyes can never truly see. The UC Berkeley researchers, based on their earlier work studying cone cells, say they’ve found a way around this limitation.
Rather than trying to mix and match different wavelengths of light to produce color, their Oz system stimulates individual cone cells using safe microdoses of laser light. By applying these doses in just the right spatial pattern to only activate people’s M cones—something that isn’t naturally possible—they’ve figured out how to produce the perception of a brand new color.
They tested the Oz system on five human volunteers with normal vision. Once they activated M-only cones, the volunteers reported seeing a blue-green color of “unprecedented saturation.” The researchers have coined this new color “olo.”
To confirm that olo is a genuine new color, the researchers also had the volunteers perform color matching tests. One of these tests involved a near-monochromatic laser, which produced the most saturated possible colors of the rainbow that can be naturally seen. The volunteers were only able to match olo to the blue-green color of this rainbow by turning down its saturation, showing that olo does indeed exist outside the natural boundaries of our color vision.
Scientists have been able to stimulate a few cone cells at a time before, but the Oz system demonstrates that it’s possible to stimulate thousands of cone cells all at once. And the researchers are hopeful that Oz can have all sorts of potential uses down the line.
“Showing olo is definitely cool, but we’re all looking toward the future for how we can use the technology itself,” co-lead researcher Hannah Doyle, a fourth-year PhD student in electrical engineering at UC Berkeley, told Gizmodo. “I’m actually now working on a project using the same exact system to simulate cone loss, like what happens in retinal disease, in healthy subjects.”
Other members of the research team are studying whether it’s possible to stimulate the retina’s cones, and by extension the brain, in such a way that a person could experience having a fourth type of cone cell. That same approach might also possibly allow people missing a cone type (like those with color blindness) to experience the corresponding missing colors, the researchers speculate.
“Essentially we feel like this is a platform that we can use to do a whole host of new experiments,” Doyle said.
All that sounds wonderful. But personally, I’m hoping that I’ll be able to see olo and otherworldly colors for myself one day.