Researchers at the University of California, Berkeley, have developed a groundbreaking technique that allows humans to perceive a new color—one that does not naturally exist in the visible spectrum. The color, unofficially named “Olo,” is described as a vivid green-blue hue that cannot be rendered on digital screens or observed in nature.
The breakthrough method, known as “Oz,” uses targeted laser pulses to stimulate individual M-cones (medium-wavelength-sensitive photoreceptors) in the human retina. Under normal conditions, M-cones are activated in conjunction with other cones, particularly L- and S-cones, which together blend into recognizable colors. By isolating and stimulating only the M-cones, researchers enabled participants to experience a novel color perception entirely distinct from known visual experiences.
The experiment involved five participants. Each one reported seeing a color that was “completely new,” unlike any they had previously encountered. To achieve this, the research team employed adaptive optics-optical coherence tomography (AO-OCT) to map each subject’s retina in detail. This precision allowed the lasers to target specific photoreceptors with micron-level accuracy.
Currently, the effect can only be achieved when participants use peripheral vision and fixate their gaze on a specific point to avoid unintentional activation of neighboring cones. However, this method opens the door to new avenues of vision science. It may offer future applications in the study of color blindness, advanced retinal diseases, and even visual augmentation for those with unique photoreceptor configurations like tetrachromacy.
While the technology is still experimental, the creation of “Olo” represents a milestone in the understanding of human color perception—expanding not only what we know about how we see, but what we are capable of seeing at all.
