Meet Olo: The Invention of a New Colour That Human Eyes Have Never Seen Before

Scientists have just created a new colour named Olo, which does not exist within the visible spectrum detectable by a normal human eye. In an experiment conducted by scientists from the University of California and the University of Washington School of Medicine [1], a new colour was generated by using laser light to stimulate only a single type of light-sensitive cone in the human eye—a colour never before seen by human eyes. The possible description of this colour is to imagine it as a hyper saturated bluish-green.

To understand the science of how new colors are created, we need to know how colors work. Let’s look at some basics and then dive into the topic of interest.

How Do We See Colour?

We perceive colour through light in the visible spectrum, which ranges from 400–700 nanometres in wavelength. Outside of this range, our eyes cannot detect light. A particular wavelength of light has originally no colour, as it is just an electromagnetic wave made up of oscillating electric and magnetic fields. The fields have no colours. The colour is perceived in our brain when these lights interact with the light sensitive cone cells in retina of our eyes.The number of cones and their sensitivity is different for humans and animals. In humans, generally there are three light sensitive cones namely L , M, and S (stands for long, medium and short wavelength-sensitive cells). A comparative signal reaching on these three types of receptive cones allows the brain to generate the perception of colour.

Each cone is sensitive to a different but overlapping range of wavelengths. The S cone is most responsive for short wavelengths (blue), the M cone is activated most by greenish light, while L cone is more sensitive than the others to longer wavelength red light. Each colour that we see depends on how these cones are activated by incoming light.

The Twist: Can We Excite Just One Cone?

The main part of the game is here: because the M cone sits in the middle of the spectrum, any light that activates it usually also activates neighbouring S or L cones, which influences the final colour perceived.

So the researchers asked: Can we stimulate only the M cone and avoid stimulating the neighbouring ones? Would that produce a new colour perception?
Yes. Eventually—they succeeded.

The Oz Technique: Birth of Olo

First, the researchers mapped the retina of each participant at cellular resolution, marked the location and type of each cone. Then, using a technique called Oz, they stimulated only the M cones using microdoses of laser light. Real-time eye tracking at 960 Hz ensured pinpoint accuracy in delivering the stimulus.

During the experiment, participants were asked to match the colour they perceived. To their amazement, there was no known colour match. They described the experience as more intense than even the most vivid blue-green shades of normal vision.

This technique works by shaping light spatially, not spectrally—essentially, it tricks the brain into seeing a new colour by targeting individual retinal cells in a way that has never been done before.

Why It Matters

This experiment is a proof-of-concept to achive an entirely new colour by tricking the human eye. This could lead to Programmable color vision beyond the natural human gamut, creating entirely new visual experiences with potential vision restoration. The outcome can provide an experimental platform that can manipulate individual neural activations at the retina.

1. Fong, James, Hannah K. Doyle, Congli Wang, Alexandra E. Boehm, Sofie R. Herbeck, Vimal Prabhu Pandiyan, Brian P. Schmidt et al. “Novel color via stimulation of individual photoreceptors at population scale.” Science Advances 11, no. 16 (2025): eadu1052.