This color didn't exist—until scientists made 5 people see it
What's the story
In a groundbreaking study, researchers from the University of California, Berkeley, have enabled human subjects to perceive a new color, termed 'olo.'
This hue, described as a highly saturated blue-green (similar to teal), was made visible using a novel technique called 'Oz,' which involves precise laser stimulation of specific retinal cells.
The research, published in Science Advances, mark a significant advancement in our understanding of human color perception.
Cone cells
Understanding the role of cone cells in color perception
Our perception of color is primarily due to specialized photoreceptive cells in our retinas called cones.
These are classified into three types: short-wavelength (S) cones, medium-wavelength (M) cones, and long-wavelength (L) cones.
Normally, when we attempt to reproduce color for someone, we adjust the spectrum of light perceived by these cone cells.
But since some cones have overlapping responses to certain wavelengths, there are theoretically colors our eyes can never actually see.
Color perception
Oz system stimulates individual cone cells with laser light
The Oz system from the UC Berkeley researchers stimulates individual cone cells with safe microdoses of laser light.
By applying these doses in a precise spatial pattern to only activate people's M cones, they have successfully created the perception of a brand new color.
This innovative technique was tested on five human volunteers with normal vision, who saw a blue-green color of "unprecedented saturation" after their M-only cones were activated.
Testing olo
'Olo' is a genuine new color
To confirm that olo is a true new color, the researchers also conducted color matching tests with the volunteers.
One such test involved a near-monochromatic laser, which produced the most saturated possible colors of the rainbow that can be seen naturally.
The volunteers were only able to match olo to the blue-green color of this rainbow by turning down its saturation, confirming that olo does exist outside our natural color vision boundaries.
Future prospects
Oz system could have numerous potential applications
The Oz system has shown that it is possible to stimulate thousands of cone cells simultaneously. The researchers are hopeful about the future applications of this tech.
Co-lead researcher Hannah Doyle said, "I'm actually now working on a project using the same exact system to simulate cone loss, like what happens in retinal disease, in healthy subjects."
Other team members are looking into if this could let people missing a cone type (like color-blind individuals) see corresponding missing colors.