Scientists Discover “Olo”: A Color Outside the Natural Spectrum

Researchers have identified a highly saturated color, dubbed “olo,” that cannot be replicated on screens, as it requires direct, precise stimulation of specific retinal cells in the human eye.

The Mystery of the Olo Color

Only five people in the world have witnessed the color olo, a hue described as having an intensity unknown in everyday life. The experiment, published in the journal Science Advances, demonstrates that human vision holds secrets that remain inaccessible through standard light perception.

Participants in the study did not view a new pigment or physical material. Instead, they used specialized equipment to precisely stimulate specific photoreceptor cells in the retina. The five test subjects, including researchers from the University of California, Berkeley, described the experience as an exceptionally saturated blue-green shade, similar to intense teal or turquoise, yet impossible to replicate on a monitor.

How the Human Eye Perceives Olo

Human color vision relies on three types of cones in the retina—S, M, and L—which respond to different wavelengths of light. Under normal conditions, these cones have overlapping sensitivity ranges, making it impossible to stimulate one type without activating others. The experimental system, known as “Oz,” bypassed this limitation by mapping a participant’s retina and delivering precise light doses to target specific cones.

By stimulating the M-cones in a way that natural light never achieves, scientists enabled the participants to perceive a color that exists outside the standard range of human experience. While the technology can control roughly a thousand cells simultaneously, it requires constant adjustments to account for the minute, involuntary movements of the human eye.

Why Screens Cannot Display the Hue

Displays such as smartphones and televisions create colors by mixing light to trigger various receptors simultaneously. Because these screens cannot selectively target individual photoreceptors, they are physically incapable of reproducing the olo signal. Any image shared online claiming to show the color is merely an approximation that fails to replicate the specific stimulation of the participants’ retinas.

The name “olo” is derived from the “0-1-0” pattern, representing the experimental goal of minimal S-cone activity, high M-cone activity, and minimal L-cone activity. While the researchers characterize olo as a “novel color,” some members of the scientific community argue it is more accurately described as an extremely saturated variation of a known hue, as it still utilizes the existing biological hardware of the human eye.