May 21, 2012

The Perfect Yellow

Jad and Robert wonder if maybe they could add to their color palette. Jay Neitz wondered the same thing, sort of. Take a monkey that can't see red, for example. Couldn't you just give them the red cones they were missing? So he took the human gene for red cones, figured out a way to inject it into the eyes of a group of squirrel monkeys, and he started doing vision tests. Day after a day for weeks. Until something remarkable happened.

And that got us thinking. Could you take Jay's experiment even further? Could add whole new cones to see a whole new universe of wavelenghts? According to Jay, we might not need to. Because it just so happens, there are already people walking around with an extra cone. Producer Tim Howard tracked down a real-life tetrachromat named Susan Hogan, then drove out to Pittsburgh to meet her and Jason LaCroix ...and administer a quick vision test that made it clear that who sees what is anything but black and white.

Next, Victoria Finlay introduces us to special strain of yellow goop: Gamboge. Raw gamboge It's a particular kind of tree sap, from the border area between Cambodia, Vietnam, and Thailand.  It takes years to collect a big enough blob to sell to paint suppliers. And in the course of those years, the sap collects a souvenirs of the things happening around it. Robert and producer Sean Cole headed to Kremer Pigments in NYC to take a look at a lump of the stuff, and Ian Garrett, the former technical director of the art supply store Winsor & Newton, tells us how the sap revealed the horrors of the Cambodian killing fields.

Bullets found in raw gamboge

Photo courtesy of Ian Garrett, Winsor & Newton.

A squirrel monkey named Dalton performing a vision test after receiving Jay Neitz's gene therapy:

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Jad: Hey, I'm Jad Abumrad.

Robert: I'm Robert Krulwich.

Jad: This is Radiolab and today we're talking about color. That actually brings us back to Jay Neitz.

Jay: I'm a professor of Ophthalmology, University of Washington Seattle.

Jad: Jay has actually spent his entire career trying to get creatures to see colors that they normally can't see.

Jay: Well, yes.

Jad: He started- This is an interesting story, by taking some colorblind monkeys, who couldn't see red.

Jay: They have blue cones, green cones, but no red cones.

Jad: Which is not unlike a lot of human males. In any case, he had these monkeys and was able to take the human gene for the red cone, wrap it in a virus, inject it into the monkeys' eyes, and bam! the monkeys suddenly had red cones.

Robert: Oh my God.

Jay: Yes. I had blue, green, and red.

Jad: Was this like a LASIKs or it's just like a 10-minute outpatient situation for the monkey?

Jay: I would say, close. Close to LASIK.

Robert: Could they then now see red?

Jay: Well, every single morning before they get their breakfast, they have to do their color vision test.

Robert: You'd say each monkey had a computer?

Jay: We had a touch screen.

Robert: The screen looks totally grey, but in that field of grey he adds a little red blob.

Jay: Right.

Jad: Now, here's the key. We used grape juice as the reinforcement for the monkeys but game is, you have to touch the blob before you get your juice. Before the surgery, they weren't seeing any blobs, and they weren't getting any juice, because all they could see was grey. A little red blob could be right there in front of them, and they never see it. The morning after their LASIK color booster shot, they still couldn't see it. Day after day they would do their test and every day they would fail.

Jay: Every day they would fail.

Jad: No blob, no juice.

Jay: It's fun for them. They get out of their cage and they talk to their friends and-

Robert: Did you fail?

Jay Yes, I failed.

Jad: You failed out there.


Jad: Another day, another fail.

Robert: Until one morning after about 20 weeks, Jay woke up the monkeys gave them the test.

Jay: They began to not fail.

Jad: Really? If you watch the video of this, it actually looks like the monkey is like, "Wow, I'm not having any failures," and check out this dot. Look at this thing.

Robert: Check it out.

Jay: It did get some sense that they felt like their life had improved.

Jad: Now, if this works so well with the monkeys, couldn't you take a colorblind human and give them back the thing they're missing?

Jay: Absolutely. We could cure color blindness in a human with exactly this technique. The only thing that we have to do is convince the FDA that the risks are low enough and the benefit is high enough that it'd be something we can do on people.

Robert: Have you tried it?

Jad: You've never tried it?

Jay: No, we've never tried it. Although I get a lot of e-mail that say, "I don't care what the risks are." I've even had offers, "How about if I come to your laboratory, and you don't tell anybody late at night, and you give me the shot in the eye and we won't tell anyone?"

Jad: Which brings us back to our original question, "If you can take a colorblind human and give them normal color vision, could you take a normal color seer and boost them to make them a little more shrimpy?"

Jay: Well, yes.

Jad: Is it sure?

Jay: Why not?

Jad: Then there's the whole FDA thing, but here's the real surprise.

Robert: Jay says, "There were some people who already a little bit mantis shrimp-like, there are color mutants, if I may call them that in the nicest possible way, among us, or-

Jad: -they're out there in theory. Okay, so here's the deal. The genes for the cones in our eyes see color, the red, green, blue cones. They're on the X chromosome. Now men as we know only have one of those.

Jay: Women have two X chromosomes.

Jad: Which means that women have two sets of these cone making genes. Normally, one set is just a spare. It's not used but still, they've got two sets.

Robert: Someone said, "Aha."

Jad: It is theoretically possible then, in some women these spare set of genes might mix up, turn on, morph into a whole new cone, a fourth cone.

Jay: We're going to call it the yellow cone.

Jad: People with normal color vision are trichromats because they've got three cones.

Jay: A woman like that would be a tetrachromat. Altogether, she'd have a blue cone, a green cone, a yellow cone, and a red cone.

Jad: She wouldn't just see more yellow, this new yellow would mix with the red and the blue and the green to create thousands, maybe millions of more shades of color.

Jay: This amazing-- technicolor that's not the right word. It's whatever would be the next kind of color that would be even more superduper.

Jad: This was just a thought experiment.

Jay: Yes, but--

Robert: Jay actually figured out a way to test for this.

Jay: We can look in people's blood, and I can say this woman has the genes for blue cones, green cones, yellow cones, red cones.

Robert: You can do a DNA test, really?

Jay: Yes.

Jad: He started doing blood tests, and he found this one woman.

Jay: She worked at the same place we did.

Jad: Crazily enough.

Jay: At the University.

Jad: He looked at her DNA, and he saw the gene for the fourth cone. Did she seem super technicolor, or how would you even know?

Jay: That was that was a problem. We thought of an experiment in order to be able to see whether or not she had this extra dimension of color vision.

Jad: He was able to produce these two yellow lights that, to us, normal trichromats look totally identical.

Jay: We're colorblind to that difference.

Jad: To a tetrachromat, a woman with this fourth cone, they would look totally different.

Jay: Yes. They brought her in. I said, "Okay, here it is. Do you see these as different?" She said, "No, I don't see them any different."

Jad: No.

Jay: The story doesn't end there.

Robert: Good.

Jad: Jay told us about a colleague of his in England-

Jay: She's at Newcastle.

Jad: -named Gabrielle Jordan, and she apparently found eight of these women with the extra cone. Out of those eight?

Jay: Seven of those women behaved exactly like the person that I had tested.

Jad: Couldn't see the difference.

Jay: One of them-

Jad: -took one look at those two yellows and said,-

Jay: "No, they look totally different to me."

Jad: One of these women saw this different. One of them had the cone but could use it, and the others had the cone but couldn't use it?

Jay: Yes. Why is that?

Jad: Yes, why?

Jay: Well, this is the part if you'd like I could tell you what my theory is of what's going on? I think that-

Robert: Jay says let's just imagine you grew up in a world without color.

Jay: Completely in a totally black and white world, houses would be painted black and white, printers would only print in black and white.

Jad: Even the TV-

Jay: -they would just have black and white TV, women's makeup would be just either dark or light.

Robert: It wouldn't make any difference if you had color vision, because you would never use that color vision, there'd be no words for color. Now, just to make it interesting, let's imagine one day, a bright red apple pops into your world. How would you react to it?

Jad: Would you see it, you think?

Jay: Well, so that's a very good question.

Jad: Maybe says Jay, even though you have the ability to see that red apple, if you've never had a chance to use that ability to practice, it may just lay dormant and that he thinks might be what happens to women living with the extra cone in our world.

Jay: They're very rarely subjected to colors that would stimulate their extra kind of cone differently.

Jad: You're saying those other colors just aren't around enough for them?

Jay: Yes, everything that we make is based on the fact that humans are trichromatic. The television only has three colors. Our color printers have three different colors. There's nothing out there that we make artificially, that a tetrachromat could see.

Jad: Jay says maybe-

Jay: -some women because they're just more aware or because of the job that they do-

Jad: -maybe someone who works with color all the time, like a florist or painter.

Jay: Little by little-

Jad: -because they're paying such close attention,-

Jay: -their brain would learn to see that difference.


Jad: Naturally, we wanted to find one of these mythic ladies.

Robert: We are hoping that mythic, maybe you know-

Jad: The reason I say that is because we tried to find that one woman that he mentioned, the one out of eight, and we had a really hard time, and we began to doubt that she even existed. Then we began to look online, and you see all these websites saying, are you a tetrachromat? Contact us. Everybody is searching for these women. We began to feel like we were chasing unicorns a little bit. Then our Producer Tim Howard claimed that he had found one.

Susan: -re-calculating.

Tim: Yes, you are.

Susan: Turn right on Sarah street.

Jad: He'd been in touch with Jay. Jay told him that he tested a woman determined that she had the fourth cone, and this woman was an interior designer, but Jay had not yet determined whether she could use her fourth cone, so we sent Tim to Pittsburgh, where she lives to see what he could find out.

Susan: Hi, there.

Tim: Hey, how are you?

Susan: Hi, I'm Susan Hogan, I am a mother of three and an interior designer.

Jad: What was she like?

Tim: She's great. You have a jukebox.

Susan: Yes, do you want me to play something?

Tim: How about number 307, it just seems appropriate because it's about color.

Susan: Whiter Shade of Pale. [laughs]

Tim: She told me a lot about how she uses color in her work-

Susan: You see the different colors of paint here.

Tim: -because she thinks a lot about it in terms of painting walls.

Susan: I know the way the sun is oriented in a room, each wall will look a different color even though you [crosstalk].

Tim: In any case, here was my plan, I'd ordered this test before I went to Pittsburgh that Jad suggested I get. It involved these little pieces of brown fabric, they all look identical.

Speaker 8: They look strikingly the same to me.

Tim: Lynn, Brenna, me, Soren-- Those are completely indistinguishable, couldn't see a difference.

Speaker 9: They all look the same to you guys?

Tim: Yes.

Jad: I'm assuming they are actually not all the same.

Tim: thas the trick, Jay said, if you show them to a real tetrachromat, they're going to be able to see these subtle differences that you and I can't see. Back to Pittsburgh. How about we head over towards the trees.

Susan: Let me take my shoes because it'll be much more fun for me.

Tim: We ended up doing the test in a nearby park. We're going to do a bunch of this if you don't mind. In the first trial, I took out three of the swatches, two that were exactly the same and one that was supposedly different.

Jad: When you took it out, could you see the difference?

Tim: No, no. I go behind the tree and I whisper int the mic, "Number three is different, number three," I hope you couldn't hear me.

Susan: No, I didn't.

Tim: I'll let you take a look. She steps back from the swatches, gives it a look for a moment, and then she says,-

Susan: Number three.

Tim: She said, third one is different.

Susan: Looks more neutral less red than one and two on the left.

Tim: One for one, luck. I went behind the tree, I changed up the swatches so that now, the middle swatch was the odd one out. Same deal, ready, set, go.

Susan: Easy.

Tim: Which number looks different?

Susan: The middle one.

Tim: Number two?

Susan: Yes.

Tim: You're right. Really? Wow. Then I figured, I got to make it harder. I switched it up and I made so that all three are different and I didn't tell her. All three are different.

Susan: All three different, I have green, red, less red. [laughs]

Jad: Knocking it out of the park.

Susan: Why didn't I do this well in my SATs, Tim?

Jad: You found her, I was sure that she was not going to be, there's no way this test can work.

Tim: Well, it actually might not have totally worked.

Jad: Wait, what, did she start to fail?

Tim: There's one little thing I didn't mention-

Jason: How are you doing?

Jad: What?

Tim: -I brought along a friend.

Jason: I'm Jason LaCroix, landscape, still life.

Tim: Thought I try him out as a control because you were thinking let's get someone who likes color but is a boy and can't be a tetrachromat. When we tried the exact same test with him, these three they look the same don't they to you, no?

Jason: I see different.

Tim: He was amazing every time, the first one on the left, he jumped out immediately.

Jason: Number three, they all three look different to me.

Tim: Wow.

Jad: Was he just as good as Susan?

Tim: Yes, I was a little bit disappointed I've got to say.

Jad: There was no way where he couldn't do it and she could?

Tim: No, I only had pieces of brown cloth.

Jad: It doesn't prove anything I guess she still might be a tetrachromat, right?

Tim: For all, I know and there was this one moment, I know it doesn't prove anything but I asked her about the sky. The sky was just quintessential sky blue, and I was like, "What do you see? She's like,-

Susan: Do you see some of the pink in the blue, because I see a lot of pink among the blue. There's red in that blue section.

Jad: She was looking up at a blue sky and seeing red?

Tim: Yes.

Susan: Do you see that?

Tim: No.

Susan: I see so much red up there.

Tim: It's kind of a cop-out but it's just that perfect sky blue. Where do you see the reds?

Susan: It's just mixed in there, one thing I don't see is any green in that blue I just see reds and especially around the white-clouded section.

Tim: At that moment, I felt like my sky is boring.

Jad: I'm so sorry for you, for us. I'm sorry for us.

Susan: How do we know that any of this makes sense?


That's the fun of it, I guess. [music]

lyrics to A Whiter Shade of Pale

And so it was that later

As the miller told his tale

That her face, at first just ghostly

Turned a whiter shade of pale

lyrics to Mellow Yellow

I'm just mad about Saffron

Saffron's mad about me

I'm just mad about Saffron

She's just mad about me

They call me mellow yellow

(Quite rightly)

They call me mellow yellow

(Quite rightly)

They call me mellow yellow

(Quite rightly)

Robert: You know what we haven't talked about yet.

Jad: What's that?

Robert: Where do the colors come from?

Jad: You mean sky colors.

Robert: No, painterly colors like marine blue.

Jad: Artificial colors.

Robert: No, they're not. That's the thing. You think they come from a factory or something but originally they came from the earth. There's one story about color that has haunted me for about a year and a half. It's so strange. I don't know if it's true or not. I don't know if-

Victoria: It was in my book, of course. It's true. [laughs]

Roberts: That's Victoria Finlay again, her book is called Color. This story starts with a particular kind of goop.

Victoria: It's a color called gamboge. It's named after Cambodia, the French word for Cambodia. It comes from the sap of a tree that grows in the Cambodia, Vietnam, Thailand border area.

Jad: This is a yellow color.

Victoria: It's a yellow color but-

Robert: -how you get it is really the sticky part.

Victoria: The way they get it is that they cut a slash in the bark, and then hitch up a tube made of bamboo.

Robert: About the circumference of a quarter?

Victoria: Yes.

Robert: Then little droplets of goop come out.

Victoria: Little tiny droplets of goop.

Robert: They fill up the tube the same way you get maple syrup or rubber.

Victoria: But they leave it for a couple of years.

Robert: Years?

Victoria: Yes. It's a really slow process.

Robert: So slow.

Victoria: Drop.

Robert: With some pretty strange things-

Victoria: Drop.

Robert: -can happen in that time.

Jad: What do you mean?

Robert: Sap has secrets.

Jad: Secrets, what secrets?

Robert: Wait a minute. After two long years, the harvesters come back and each of those tubes-

Victoria: -is now full of this, quite like plastic. It's got that plastic resiny kind of feel.

Robert: That's just the beginning. The resin makes this incredible transformation which we actually saw Sean and I.

Georg: Hello.

Robert: Hi.

Robert: Thanks to this guy.

Georg: My name is Georg Kremer. I'm a colorman.

Robert: He owns Kremer Pigments in Manhattan and he sells in this gamboge.

Georg: It is an important yellow.

Victoria: It's amazing when you use it.

Speaker 13: We have powdered and the resin form.

Victoria: When you have a look at it-

Georg: Look at this here.

Victoria: -it's just like this dull lucre brown color.

Robert: You imagine like a ball of earwax.

Victoria: I know you think that's not very interesting.

Robert: Dusky sort of.

Victoria: That's a very boring color but then you put a drop of water on it.

Robert: Or you grind it up in a bowl with a little water.

Georg: You'll find that it looks like this. This here.

Robert: There it is.

Georg: There's a little bit of white.

Victoria: It's bright.

Robert: Very bright yellow.

Victoria: It's bright, fluorescent yellow.

Robert: Suddenly it's like pow!

Victoria: It is quite an exciting color.

Robert: Very, very well.

Victoria: I carried one around for ages. It's like to have a look at this color, look how boring it is. Now put a drop of water on it showing kids and I was really happy. I even gave it to one kid who was just so delighted and it was only afterwards that I found out that it's so dangerous.

Jad: It's dangerous. Why?

Robert: Why?

Georg: You get a bad diarrhea. [laughs]

Ian: When the guys used to chip in small pieces, there was actually a time built-in to visit the toilet at least once an hour.

Robert: Ian Garrett knows that because he was technical director at this art supply company called Winsor & Newton in England. Here's what really got us interested in all this. Back in the 1980s Winsor & Newton would get these shipments of gamboge from Cambodia and they would take it to this production room.

Ian: It quite a dusty area just had a table in there.

Robert: Big old table where the workers would sit.

Ian: Then they would have this hammer, put the gamboge pieces on this lump of iron, and then hit it and shatter it into small pieces.

Victoria: Because that's how they make it into a usable sellable paint.

Robert: One day is one of the workers was chipping and scraping at the resin.

Vitoria: There they were.

Robert: They found something in the resin that they didn't expect.

Victoria: They found bullets.

Jad: Bullets? Like in the hunks of resin.

Victoria: Lodged in them, yes.

Robert: Sometime in that two-year drip process toward the end probably as the resin was getting thick a bullet went whizzing through the air. It went flat into the goop and stayed there. Actually, it wasn't just one bullet.

Ian: There is a total of about a dozen.

Robert: Those are just the ones he found lying around the factory. There were probably many more.

Ian: They fall into two sorts. There's a very sharp pointed one about just over an inch long and then the other type, a small barrel-shaped, which are about three-quarters of an inch long about half a dozen of each. How they got there and what they passed through on the way into the gamboge, I'm not sure.

Robert: What we do know, of course, is that those years in Cambodia were years of war and murder. A million and a half people died there most of them in the killing fields. That's the same place where you find the gamboge trees.

Vistoria: It's shocking, really because those were just random little bamboo tubes hanging on the trees. What happened in that grove? What terrible things happened?

Jad: The proposition here would be that at some point maybe because of the famous killing fields that some 14-year-olds with Kalashnikov rifles after finishing a series of murders or just shot butts of bullets.

Victoria: They would have just sprayed that grove in order to get into the little tiny bamboo canisters collecting this gamboge. They would have had to have sprayed that entire grove with machine-gun bullets. In that year or two years, somebody murdered people I should think.

Ian: Well, it's not necessarily a battle scenario. It could have been target practice. You see these things hanging on the side of a tree you want to practice your marksmanship.

Jad: There is a way in which there's violence in this color. It makes me wonder about-- Does it ever give you a pause?

Ian: Does it ever give me what? Sorry.

Jad: Pause.

Ian: Pause. Not really. We were too remote bought it from a guy in Holland who bought it from an exporter who got it from Lord knows where in Cambodia.

Jad: The idea that it could have been attached to that bloodshed, does that bother you at all?

Ian: Are you say saying them do I think it's morally acceptable? Is that what you're asking me?

Jad: Yes.

Ian: No, it wasn't Winsor & Newton who discovered these things. These things were demanded by customers.

Robert: You're a hard-hearted man, I feel.


Ian: I had never thought about it until you pitched it like that.

Jad: As we kept on talking, Ian made it clear it wasn't that he hadn't thought about the violence, per se. It's just it wasn't breaking news to him. They sell some pigments that come straight out of hills that are right in the middle of war zones. Colors are sometimes soaked in blood. That's just how it is.

Ian: On the other side of the coin I've made it my career in 40 years to make artists paints on the basis that people who paint tend not to make war. It's a peaceful occupation.

Georg: That's more or less what they used in the [crosstalk]

Robert: Georg Kremer who runs the paint shop, he was pretty much of the same mind. You could think of it this way. Imagine the first person to ever find this brilliant yellow maybe 10,000 years ago. He's walking through the forest after it's rained and he sees it there on a tree and he's amazed. He put his finger into the yellow and then dab some on his face and he feels instantly beautiful like larger than himself.

Georg: It is about being related to something transcendent.

Robert: That says Georg is the other side of the coin.

Georg: -to an upper high whatever. Therefore they probably used it for all sorts of ceremonies.

Jad: Marriages, feasts, maybe war paint to feel invincible. Any moment he suspects it needed to be pulled out of the ordinary and lifted up.

Georg: There you need something that is quite-- something that is beautiful and special. This yellow gives you something special. It is a perfect yellow. [music]

Jad: Thank you to Victoria Finlay. Her book is called Color, short and simple, to the point.

Robert And to Ian Garrett of Winsor & Newton who did not wither under our withering moral attack.

Jad: On the contrary.


Annie McEwen: Hi, my name is Annie McEwen. I'm a producer at Radiolab. I wanted to talk about this thing we do at Radiolab because I like it. We have this thing, it's a newsletter. Big surprise, every show has a newsletter, but ours, I think, is pretty fun.

Matt Kielty: Oh, it's so fun.

Annie: Matt Kielty.

Matt: Hello.

Annie: Fellow-producer at Radiolab. What is your favorite part of the newsletter?

Matt: My favorite part of the newsletter is-- First, it's getting it and seeing it in my inbox, and then second, it's opening it. Then third, is just hitting PgDn on my keyboard till I get to the very bottom of the e-mail-

Annie: Oh, that's good.

Matt: -because you know what's at the bottom of the e-mail?

Annie: What?

Matt: You know.

Annie: Staff Picks.

Matt: Staff Picks at the bottom of the e-mail.

Annie: Yes.

Matt: How great is that?

Annie: It's great.

Matt: Just stuff that we like, stuff that we're into.

Annie: What are your favorites?

Matt: Some of my favorite staff picks-- There was the one video where it was 17 babies on a hamster wheel.

Annie: Really?

Matt: Oh, the article about the guy who ate 17 burritos.

Annie: Matt, you're not saying real ones.

Matt: Okay, what's your favorite staff pick?

Annie: My favorite one ever?

Matt: Yes.

Annie: Well, it's hard to say. One of my favorite ones ever was Robert talking in delightful detail about The Great Sausage Duel of 1865.

Matt: Classic pick.

Annie: Classic. Molly's bedbug pajamas.

Matt: Oh, yes. That was a scary time.

Annie: Tracie's pasta recipe which I did not make because I don't like to cook, but I'm just proud of her.

Matt: Actually, it's really simple.

Annie: Urgh.

Tracie: It was just online. It's a 28 ounce can of tomatoes, five tablespoons of butter, a pinch of salt, an onion, and you cook it in a pan for 45 minutes, all right?


Matt: Thank you, Tracie. I'm telling you, everybody's loving this pasta dish.

Reviewer 1: Oh, I do definitely.

Matt: That woman. This guy.

Reviewer 2: Sure.

Reviewer 3: Oh, I think it's wonderful.

Reviewer 4: Very tasty. Pasta every day.

Annie: Matt, you're not helping. Anyway, our newsletter has cool stuff in it like staff picks. It also tells you when an episode is dropping.

Matt: It's free.

Annie: It's free.

Matt: We're just going to hit it, just say you should sign up.

Annie: Just sign up. You can sign up in about 30 seconds at or text "RL News", as in Radiolab News, to 70101. That's "RL News" to 70101. Thank you.


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