Introducing “Olo”: A Potentially New Color

Scientists have proposed the existence of a “new color” named “olo,” which they assert allows individuals to see something that does not coincide with any hues in our routine visual experiences. Olo is characterized by a deeply saturated greenish-blue and was created using a novel technique that activates the eye’s photoreceptors in an unconventional method.

The authors of the study state, “We name this new color ‘olo’.” However, the question arises: can it genuinely be labeled as a “novel color” as proclaimed by the researchers? The essence of color includes three elements: hue, saturation (or chroma), and value (or brightness). While the study indicates that olo possesses an unusually high level of saturation, its hue is still tied to blue-green. This conversation about its classification is better suited for color scientists and online discussions. Regardless, individuals who have experienced olo describe its visual effect as intriguingly unfamiliar.

Participants observed that olo, when presented in their prototype system against a neutral gray background, emerged as a never-before-seen blue-green with exceptional saturation. To properly match olo with the closest monochromatic color, they found it necessary to desaturate olo by introducing white light, demonstrating that olo exists outside the conventional color spectrum.

Descriptive names offered for olo included terms like ‘teal,’ ‘green,’ ‘blue-greenish,’ and ‘green with a hint of blue.’ Consistently, subjects rated the saturation of olo as a perfect 4 out of 4, contrasting with an average rating of 2.9 for nearby monochromatic colors of similar hue.

Understanding Color Perception

Color perception is a phenomenon we experience when specific wavelengths of electromagnetic radiation activate the cone cells in our retina, which then transmit signals to the brain. The back of our eyes contains three types of cone photoreceptors: short-wavelength (S), middle-wavelength (M), and long-wavelength (L). Each type has overlapping spectral sensitivities, which implies that any light wavelength influences at least two types of cones simultaneously, thereby restricting the spectrum and saturation of colors we can perceive.

The Oz Technique for Color Creation

In a recent study from the University of California, Berkeley, researchers crafted a method to directly stimulate a single cone by directing focused laser light at it, a process termed Oz. By applying this technique to five human subjects, the researchers successfully activated M cone cell activity, prompting participants to experience the new color as “blue-green of unprecedented saturation.” Additionally, they manipulated this technique to stimulate thousands of individual cones, allowing them to produce images and visual representations.

Traditional color technologies, like current computer screens, work via a principle called spectral metamerism, which combines different light wavelengths to replicate how our eyes perceive specific colors, prompting the cone cells and our brains to recognize a color match. This methodology has been in use since at least 1861, when James Clerk Maxwell demonstrated layering red, green, and blue images to create full-color visuals.

In contrast, the Oz technique employs a different method. Rather than modulating the spectrum of light, it governs the spatial distribution of light on the retina through a principle known as spatial metamerism. This enables the generation of a wide variety of colors using a singular monochromatic light, eliminating the necessity for the three primary light colors.

Expert Perspectives on the Research

Experts commenting on this new study recognized that while it introduces promising practical advancements, certain elements of single-cone stimulation are not entirely novel. Dr. Misha Corobyew, a Senior Lecturer in Optometry and Vision Science at The University of Auckland and not involved in the study, noted, “When only M cone is stimulated, observers report seeing an unusually saturated greenish-blue. Typically, a focused point source on the retina stimulates multiple cones due to optical limitations. Adaptive optics, which astronomers use to observe stars, is usually employed to mitigate this. The innovation of this paper lies in stimulating a multitude of individual cones to generate an image.”

The study is documented in the journal Science Advances.