Short Wave - Unveiling Olo — A Color Out of Oz!

Episode Date: June 6, 2025

"Olo" does not exist in nature, nor can it be found among paint cans. But for a very select few, olo can be seen — through the intervention of careful computing and lasers. A team led by vision scientist Austin Roorda and computer scientist Ren Ng at UC Berkeley figured out a method for stimulating only one specific subset of cones of the retina. It's the only way to view this spectacular teal. Creating the color is helping push the boundaries of vision science.Follow Short Wave on Spotify, and Apple Podcasts.More questions about the science behind our everyday lives? Email us at [e-mail]. See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Color is a trick of the light and a creation of our brain. It's actually very challenging to study color because of the complexity of it and how the perception is so context-dependent. Austin Rurta is a professor of optometry and vision science at UC Berkeley, and he's likely the first person in the world to ever see a new color. meaning a color that does not exist in nature and was developed entirely in a lab. Austin and his collaborator, computer scientist Ren Ong, call this novel color Olo.

It's blue-green, it's a teal color, but it's just more saturated than any teal you can see in the natural world. And to make this super-saturated color, the team used a technique they call Oz, named after the movie The Wizard of Oz, which, as you may remember, starts in black and white. until Dorothy emerges into a technicolor world. Toto, beating we're not in Kansas anymore. Must be over the rainbow. And so, Oz, in a way, to me, it's that effort to evoke a new sensation of color. And so we go from a normal colored world

to this extraordinarily colored world through direct manipulation of the self. Was it like that for you? Like I see the world in basic color, and this is super-souper-south. Well, I would say yes, but, you know, we're not looking at this in an IMAX theater. Our display is the size of an icon on your cell phone, or it's the size of your fingernail held at arm's length. Today on the show, seeing Olo, how color perception works and how a swatch of color created by machines is pushing the boundaries of vision science.

I'm Emily Kwong, and you're listening to Shortwave from NPR. Okay, Austin and Wren, let's talk about color. What is color, Austin? And for those of us who can see color, how are we able to? So humans have three types of cone photoreceptor, and they're sensitive to the long, middle, and short wavelengths of the visible light spectrum. So they're called L, M, and S. And with these three types of sensor,

we can send information to the brain that will inform the brain about color. So it's the brain that looks at the subtle differences and the excitation of those three cone types to generate a percept of the color. So with just a mere three cone types, humans are able to differentiate arguably up to 10 million different hues in the visual world.

And that's really through the extensive processing that the brain does. It's a very important part of the process. The three types of color cells in the retina, the reason they're sensitive to these three types of different parts of the visible spectrum is because they are filled with photopigments, which are proteins. Okay. And those proteins come from our DNA, from three genes. Okay, so literally our color vision is baked into our DNA, literally.

Are different people seeing different colors? If all three of us here were to look at sunflower, would the yellow of the petals look a little bit? different because are our cones unique to us in some way? Absolutely. And the people see colors in the world and experience them differently for sure. And if you're a colorblind person that is what we're called dichromatic or hard dichromatic is missing one of those three genes completely.

Okay. And when that happens, then what is that vision like? Actually, it's really hard to know what the experience of having. another person's vision is, it's sort of impossible, right? And there's three types of this type of colorblindness. But the most common type would be an experience, we think, that sees the world only in shades of blue and yellow. Okay, so you don't see all the colors of the rainbow.

You can't order the colors of the rainbow because you don't perceive them. Okay. You perceive them as shades of blue and yellow. So absolutely, we're all seeing the world differently. Fascinating. Okay. Let's talk about your study. You set out to stimulate.

M cones without stimulating any neighboring L or S cones. And that doesn't happen in nature. So what did you want to know? If you did that, I guess the question becomes, do you see a square of color? Or is your brain just confused about what you see there? Do you see a black hole? Or, you know, what is it? And I thought, well, you know, I guess you would see a color.

And I wanted to know, hey, does that look like? What does it look like? What does it look like the green is green you've ever seen? And I want to call out James Fong and Hannah Doyle, amongst the many collaborators, but really they stand out the people that did the hard work, had the perseverance and the smarts, the talent

to really chase this down. It was so challenging, but the fruits of the labor is so valuable because it is really something's never been done before, so there's no chartered course to it. Right, and you did see something. You saw Olo. What's required to see this novel color?

Yeah, there are a number of parts. First of all, in order to be able to consider even targeting only the M-Cones. You have to have a map of the cone mosaic of the three types of cones. So every subject in the study had to travel to the University of Washington to our collaborator's lab

where he has a device to image the retina and with a special type of imaging called optical coherence tomography, he was able to label the cone types as being L, M, or S. So he kind of mapped everyone's icons. That's right.

So then when we go to the lab, in the lab here, there's a few steps. One is you need to dilate your pupil. And then we bite into a bite plate called a bite bar, which gets locked into the device. So your head is held perfectly rigid. And then somebody else will align you in X, Y, and Z to get your pupil aligned with the output aperture of the system. This really reminds me of going to the eye doctor. Exactly. Does my vision.

Go on. That's right. And then now there's one little important fact is that classifying the cones or generating maps of the cones is difficult. And nobody has ever mapped the cones right along the line of sight in an area called your phobia because the cones are really densely packed there. So we instead we map the cones a little bit away from the phobia, about about a half a millimeter. away from the center of the phobia. And initially, while everything's getting set up, things look green, or just a regular green, then once everything gets into place and you're carefully fixating,

then you have this moment where it just turns this saturated teal. And I was aware at that moment that we had succeeded, that we had created and that we were able to stimulate only the M-cones. And James Fong, the lead author on the paper, he invented the name OLO because it's a binary code for 010, which represent the stimulation of the L, M, and S cones. That's so smart. And as I understand it, you also had this teal laser next to OLO, and it was a laser containing the most saturated natural light you were able to generate. So steady participants could compare the colors, right? That's kind of how you show that Olo isn't just teal.

It's a completely different color. That's right. What do you say to folks who wonder if Olo exists in nature in such a way that maybe other animals could see it? I love that question. To be clear, animals don't see the world in color anything like a human does, right? Nothing like a human does. Animal eyes are vastly different than ours, and even our closest cousins on the evolutionary tree, their genes for those photopigments that we talked about earlier,

they're not the same as for us. They don't have the same number as us, and they don't have the same genetic sequence, so its functional effect is in the world for detecting light, is totally different. We know that. Like hummingbirds, people have probably heard or may have heard, some of the species can see in UV light.

We're blind to UV light as one example, but every animal sees it completely differently. Another way you think about it is that, you know, we all look at a TV, you're like, wow, that color's pretty good. When your dog or your cat is sitting there looking at that TV, they do not see that and be like, wow, that kind of looks like, you know, that photo that we all took together outside the house this morning. Just the colors don't look right, okay? How do you know? My cat can play the same video games as me.

I think he's following. You might be following, but the colors won't look the same. Yeah. So back to this question about, you know, could there be, you know, an animal that could see Olo? I received that question first. Oh, what a great question. But it's actually that there's no way for that to happen because the experiential nature of the color for different species

is just so vastly different. Yeah. I recognize that you need a machine to see OLO, but for those of us at home, is there any way to approximate the OLO experience and to trick your eyes? Now, there's one type of... a situation where you can get an impression of what OLO might be.

And that is if you desensitize or if you're exposed to a bright red light for a period of time. I'm going to do this at home. I want to see Olo so bad. Okay. So if you look at red light and you kind of adapt to red light, by looking at red light too much for a long period of time, you may desensitized to it or adapt to it. And then immediately following the adaptation to red light, you show a green light. light, and that approximates the condition that we generate with OLO, whereby the M-Cones are

preferentially stimulated more than what normal natural light would do. And so if you wanted to get a rough idea of what OLO looked like, you could do this adaptation trick. Now, the difference is that when we deliver OLO, we can make it last. It can persist. Wow. You speak like such a steward of a color. And it's so, it's funny to me because, like, the pop culture craze around seeing Olo has got to be pretty funny for you all to witness. I read about an artist from the UK Stuart Semple who is selling for $10,000 pre-orders of a paint based on Olo called Yolo, which is, you know, you only live. Oh, I know. We love that. What has been the funniest Olo homage or Olo plea that you've read about or seen?

Well, I think I love Yolo. The reason I loved it, of course, you can't make a paint that recreates Olo. No, it seems like saturation is such a big part of this. That's right. It's all about saturation. It's not the hue. That's right. Stuart Semple totally realized that, and his paint was meant to, sort of evoke a sensation, a feeling of OLO. And from what he describes, he kind of achieved that by adding some fluorescent components.

Some say, well, Olo's no different than Taco Bell's Baja Blast. Okay. Some people say, I had to color Olo on my Nike sneakers back in 2015. And so it's all been fun. They're experiencing FOMOLO, which that's what that is. FOMO. Yes, we've had a bit of that. Fear of missing out on OLO.

That's right. Thank you for sharing OLO with us on Shortwave and with the world. And we wish you luck with future adventures and advances in color, in human color vision science. Well, it's been a real pleasure to talk to you. Thanks for having us on, Emily. Shortwavers, please like, follow, or subscribe to our show now. You will get a fun and fresh science episode in your feed four times a week. Today's episode was produced by Rachel Carlson.

It was edited by Rebecca Ramirez. Tyler Jones checked the facts. Kwayce Lee was the audio engineer. Beth Donovan is our senior director and Colin Campbell's our senior vice president of podcasting strategy. I'm Emily Kwong. Thanks for listening to Shortwave from NPR.