In a groundbreaking study, researchers have named a new color 'olo.' But can this truly be classified as a “novel color”, as the authors boldly assert? The essence of color perception is comprised of three components: hue, saturation (or chroma), and value (or brightness). The study indicates that olo exhibits a remarkably strong saturation, yet its hue remains firmly rooted in the blue-green spectrum. This prompts an intriguing discussion among color scientists and enthusiasts alike, but for now, we will leave that debate for the experts and the comments section.
Regardless of the precise definition, those who have encountered olo describe it as offering a visual experience that feels subtly unfamiliar. According to the researchers, "Subjects report that olo in our prototype system appears blue-green of unprecedented saturation when viewed against a neutral gray background." Interestingly, participants have noted that they must desaturate olo by introducing white light before they can achieve a color match with the closest monochromatic light. This observation serves as unequivocal proof that olo lies beyond the typical color gamut.
Various color names have been suggested for olo, including 'teal,' 'green,' 'blue-greenish,' and 'green, a little blue.' In terms of saturation, subjects consistently rated olo as a perfect 4 out of 4, compared to a lower average rating of 2.9 for near-monochromatic colors of similar hue. This stark difference highlights olo’s remarkable saturation and uniqueness in the realm of color perception.
Color is a perception that arises when specific wavelengths of electromagnetic radiation stimulate the cone cells in our retina, triggering signals that the brain interprets as color. Our retinas are coated with three types of cone photoreceptors: short-wavelength (S), middle-wavelength (M), and long-wavelength (L). Each of these cones possesses overlapping spectral sensitivities, which means that any given wavelength of light can stimulate at least two types of cones simultaneously. This overlap ultimately limits the range and saturation of colors we can perceive.
In an innovative study conducted by scientists at the University of California, Berkeley, a method has been developed to directly stimulate a single cone using focused laser light, referred to as the Oz method. By employing this technique on five human subjects, researchers successfully triggered M cone cell activity, leading participants to describe the color as “blue-green of unprecedented saturation.” This groundbreaking technique also enables the stimulation of thousands of individual cones, facilitating the creation of images and visuals that were previously unattainable.
Conventional color technologies, such as the computer screens we frequently use, rely on a principle called spectral metamerism. This method involves blending various wavelengths of light to replicate the way our eyes perceive specific colors, effectively prompting the cone cells in our retinas and our brains to see a match. This technique has historical significance, dating back to at least 1861 when James Clerk Maxwell captivated audiences at the Royal Institution by layering red, green, and blue images to create full-color visuals.
In contrast to traditional methods, the Oz technique employs a different strategy. Instead of adjusting the light spectrum, it focuses on controlling the spatial distribution of light on the retina, a concept known as spatial metamerism. This innovative approach allows for a broad spectrum of colors to be created using a single monochromatic light source, eliminating the need for the conventional three light primaries.
Experts have expressed that while the research presents some promising practical innovations, certain facets of single-cone stimulation are not entirely new. Dr. Misha Corobyew, a Senior Lecturer in Optometry and Vision Science at The University of Auckland, who was not involved in the study, commented, “When only the M cone is stimulated, observers report seeing an unusually saturated greenish blue. Typically, a focused point of light, such as a star, excites multiple cones due to optical constraints. To address this, adaptive optics, a technique used by astronomers to observe stars, is employed. While single cone stimulation has been recognized earlier, this paper’s novelty lies in its application to stimulate numerous individual cones and produce coherent images.”
As the study of olo and color perception continues to evolve, it opens new avenues for understanding how we experience color and the potential for new technologies in visual representation.
