"Breaking Boundaries in Color Science: The Fascinating Story Behind 'Olo'!
A group of researchers says they’ve uncovered a new color invisible to the human eye without the aid of advanced technology.
Scientists in the United States revealed they managed to "experience" the new color, dubbed "olo," by directing laser pulses into their eyes with the help of a device inspired by the Wizard of Oz.
Olo isn’t visible to the naked eye, but the five individuals who have witnessed it compare its appearance to a shade resembling teal.
On April 18, professors from the University of California, Berkeley, and the University of Washington School of Medicine shared their discovery of a color outside the range of human vision in an article published in the journal Science Advances.
They revealed that they developed a method called Oz, designed to "fool" the human eye into perceiving olo. The technique takes its name from the Wizard of Oz.
In The Wonderful Wizard of Oz, published in 1900, Frank Baum told the story of a man who uses clever illusions to convince the people of the fictional land of Oz that he is a wizard. One example is the Emerald City, the capital of Oz, which is so dazzlingly bright that visitors must wear special glasses to shield their eyes. These glasses, a part of the wizard's deception, make the city appear even more vibrant and magnificent.
The human eye detects color through three types of photoreceptor cells, known as "cone cells," in the retina. S cones respond to shorter blue wavelengths of light, M cones to medium green wavelengths, and L cones to longer red wavelengths.
"The signals from these cones are processed through a detailed network of cells in the retina, which refine and combine the information before transmitting it along the optic nerve to various regions of the brain," explained Francis Windram, a research associate in the Department of Life Sciences at Imperial College London, in an interview with Al Jazeera.
The visual information is transmitted to the visual cortex, a specific region of the brain.
In typical vision, the M cones work in conjunction with the nearby S and L cones, meaning any light that activates the M cones also stimulates the other two types. The M cones do not operate independently.
"There is no wavelength on Earth that can solely activate the M cone," explained Ren Ng, a professor of electrical engineering and computer science at UC Berkeley, in an article featured on the university's website.
"I started to wonder what it would look like if we could exclusively stimulate all the M cone cells. Would it create the most intense green you've ever seen?"
To explore this, Ng partnered with Austin Roorda, a co-creator of the Oz technology and a professor of optometry and vision science at UC Berkeley.
Oz, which Roorda described as "a microscope for examining the retina," uses small laser light doses to precisely target individual photoreceptors in the eye. The technology, which requires careful stabilization during use, is already employed in research on eye diseases.
The research with Oz started in 2018, led by James Carl Fong, a PhD student in electrical engineering and computer sciences at UC Berkeley. Hannah Doyle, another doctoral student at Berkeley, conducted the experiments that allowed human participants to observe the newly discovered color, olo.
Is olo truly a completely new color?
The hue of olo has always been present, but it lies outside the range of colors visible to the human eye. There are other such colors that we cannot perceive. Therefore, olo is not a new color in the physical or scientific sense.
However, "from a sociolinguistic viewpoint, if people start assigning new names to colors that were previously indistinguishable due to this technology, then perhaps! It ultimately depends on how it's interpreted," Windram explained.
Five people have seen the “new” colour – four men and one woman. All had normal colour vision.
Three of the subjects, including Roorda and Ng, are the co-authors of the research paper while the other two are members of the participating lab at the University of Washington and were unaware of the purpose of the study before they took part.
Those who have witnessed olo describe it as a teal or green-blue shade, though one unlike anything they had encountered before.
In the UC Berkeley article, it is referred to as a "blue-green color of unmatched intensity."
"It appeared as an incredibly saturated teal... the most vivid natural color seemed dull in comparison," Roorda explained.
"I wasn’t a participant in this study, but I've seen olo since, and it’s truly striking. You can tell you’re looking at something intensely blue-green," said Doyle.
The researchers noted that an image of a teal square comes closest to representing olo’s color. However, this square is not actually olo-colored, as the human eye cannot perceive the shade.
"We won’t be seeing olo on any smartphone screens or TVs anytime soon. It’s far beyond current VR headset technology," Ng stated, as reported by the UK’s Guardian newspaper.
Researchers at UC Berkeley are investigating whether Oz technology could benefit individuals with color blindness.
Windram explained that the effectiveness would depend on the specific type of color blindness a person has. The most common form, deuteranomaly, reduces sensitivity to green light.
"In this case, a miniaturized version of this technology could potentially correct the issue by directly stimulating the cones when the right light frequency reaches them," Windram stated.
He also emphasized that promotional materials for the research feature images of the Oz experiment on a carefully stabilized table.
"This would involve significant effort to miniaturize the technology, and it's probably a long way from being realized. Since the laser needs to precisely and stably target the correct cones to stimulate them, it might not be technically feasible as a method of vision correction," he explained.
Windram explained that the concept of color involves three key elements: the physical, which deals with the wavelengths of light that reach the eye; the neurological, which refers to how the brain processes these light signals; and the societal or linguistic aspect, which focuses on how colors are named.
"In the end, I might see a color and call it 'red,' while someone else might name it 'rot' or 'rouge'... or another person could look at it more closely and say 'claret' or 'crimson,'" he said.
To explore this idea, neuroscience and AI researcher Patrick Mineault created a website for fun in September 2024, where users can take a test to compare their color perception with that of others.
Humans can also perceive colors differently depending on factors such as the "temperature" of light. This was evident when a photo of a dress went viral in 2015, sparking a debate on social media about whether the dress was white and gold or blue and black.
Windram pointed out that people’s opinions about the dress color were influenced by their assumptions about whether the photo was taken under warm or cool lighting.
For instance, humans perceive three primary wavelengths related to red, blue, and green light, while the mantis shrimp, a small crustacean, can detect 12 different color channels, far surpassing the human range. According to the Australian Academy of Science, the mantis shrimp can also sense ultraviolet and polarized light, which are invisible to humans.
However, while humans can blend two colors and see intermediate shades—like perceiving purple as a mix of red and blue—the mantis shrimp's eyes cannot combine color receptors in the same way.
On the other hand, dogs have only two types of cones and primarily see shades of yellow and blue.
For more fascinating insights into color perception and how different species experience the world, visit MBBReviews ffor expert articles and reviews on the latest scientific discoveries.
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