A team of scientists believes they’ve discovered a new colour—one that falls outside the range of normal human vision. Dubbed “olo,” it’s described as an ultra-saturated, bluish-green hue that can’t be seen in the natural world without the help of cutting-edge technology.
The research, published in Science Advances, involved “human subject experiments” using a prototype laser device named Oz. The device was able to target individual photoreceptor cells in participants’ eyes—something that’s not possible under natural conditions.
Specifically, researchers stimulated the eye’s M cone cells—responsible for perceiving green—without activating neighbouring L (red) or S (blue) cones. This selective targeting created a signal the brain doesn’t normally receive, triggering the perception of a colour never before seen by the naked eye.
“Theoretically, Oz enables display of colours that lie beyond the well-known, bounded colour gamut of natural human vision,” the researchers wrote. “In normal colour vision, any light that stimulates an M cone cell must also stimulate its neighbouring L and/or S cones… however, Oz stimulation can by definition target light to only M cones and not L or S, which in principle would send a colour signal to the brain that never occurs in natural vision.”
In other words, Oz bypasses the usual colour-processing pathways to create a new sensory experience. Study co-author and electrical engineer Ren Ng, likened it to seeing red for the first time after a lifetime of only knowing pink.
“Let’s say you go around your whole life and you see only pink, baby pink, a pastel pink,” Ng told BBC Radio 4. “And then one day you go to the office and someone’s wearing a shirt, and it’s the most intense baby pink you’ve ever seen, and they say it’s a new colour and we call it red.”
Aside from being a mind-bending discovery, the research could have practical benefits too. The scientists say this technology may open up new possibilities for eye problems such as colour blindness research. In theory, Oz could be used to explore how the brain processes colour, and possibly restore colour vision in people with red-green colour blindness.
Globally, around 300 million people are colour blind—so this kind of research could pave the way for a significant breakthrough.
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