Scientists report discovery of a never-before-seen colour
Researchers in the United States say they’ve uncovered a new colour unlike anything previously seen by the human eye.
The vivid blue-green shade, now named “olo,” was observed during an experiment that used laser pulses to trigger a rare visual response in the retina.
The study, recently published in Science Advances, involved five participants with normal vision.
Scientists used a specialised optical setup to directly stimulate the retina’s M-cone cells, which detect medium wavelengths of light, while avoiding the neighbouring L- and S-cones that register long and short wavelengths.
This type of stimulation does not naturally occur in everyday life, and the resulting perception was unlike anything the participants had seen before.
The unique reaction in the brain created what they described as a new and “highly saturated” colour — something outside their known visual experience.
Professor Ren Ng of UC Berkeley, one of the study’s co-authors and also a participant, likened the experience to a major shift in perception: “It’s like someone who has only seen pale pink being shown red for the first time.”
The colour “olo” does not exist in the natural world and cannot be seen without artificially recreating the exact retinal stimulation conditions.
However, this breakthrough raises fascinating questions about the human visual system.
Some vision scientists have cautioned that it may not technically be a new colour, but rather a unique neural response caused by the unusual cone activation pattern.
Still, the implications are significant.
The research could pave the way for advancements in understanding colour perception and might one day lead to new treatments or technologies for colour blindness.
For now, olo remains an unseeable colour to the general public, only visible under carefully controlled lab conditions.
But its discovery hints at untapped dimensions within the visual spectrum, showing that even in 2025, our understanding of sight is still evolving.