Scientists unveil a colour never before seen by the human eye

In a ground-breaking experiment, scientists have discovered a brand-new colour, one they say has never been seen before. Dubbed ‘olo’, the colour is described as an intense blue-green that sits outside the usual range of what the human eye can see. (Sydney Wray)

In a ground-breaking experiment, scientists have discovered a brand-new colour, one they say has never been seen before. Dubbed ‘olo’, the colour is described as an intense blue-green that sits outside the usual range of what the human eye can see.

A study, published in the journal ‘Science Advances,’ details how a team of researchers from the University of California, Berkeley, and the University of Washington pioneer a new technology called Oz. This innovation allows scientists to stimulate individual photoreceptor cells in the human retina using laser light.

“The Oz system represents a new experimental platform in vision science, aiming to control photo receptor activation with great precision,” the study says.

During their experiment, researchers shone a laser beam into the pupil of one eye of each of the study’s five participants, three of whom are the study’s co-authors. All of the participants have normal colour vision.

The human eye typically sees colour by combining signals from three types of cone cells—S, M, and L cones—each sensitive to blue, green, and red light. Normally, light that activates one cone type will also activate others, which limits the range of colours we can perceive.

The Oz system, however, breaks this rule by selectively targeting only the M (green-sensitive) cones with laser light, leaving the neighbouring S and L cones unaffected leading the participants to see a colour that doesn’t exist in nature.

“By activating only the M cones, we elicited a colour beyond the natural human gamut,” the researchers wrote. They describe the colour as a blue-green of “unprecedented saturation.”

The team believes Oz could one day help improve tools for studying colour blindness or lead to new technologies for creating colours in digital imagery.

“This new class of programmable platform will enable diverse new experiments,” the study noted, including possibilities for probing the plasticity of human colour vision.