Adam Rogers, WIRED magazine: His new Book!

Andrea Macdonald, founder of ideaXme interviews Adam Rogers, who is Senior Correspondent at WIRED magazine and a New York Times best-selling author. They talk of Adam’s new book:

Full Spectrum: How The Science Of Color Made Us Modern.

“To the extent this book has a single take away, I hope that colour is more widely recognised as this amazing interaction between the world that exists outside our heads and the one that exists inside our heads.

To me, colour is as much a thing that has driven economies and historical change as something that sparks the desires of human beings to change their environment. All the things that technology is really about. It is also a way for us to understand the places where ourselves, our minds are affected by it and then impact the world that we live in”. Adam Rogers comments in his ideaXme interview.

Adam Rogers, WIRED magazine. Credit: Photo by Jenna Garrett.

Andrea Macdonald, founder ideaXme: [00:12:26] Who are you and what do we need to know?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:12:30] My name is Adam Rogers, I wrote a book called Full Spectrum: How the Science of Color Made US Modern. The basic premise of the book is that there is fundamental science and technology behind the way humans both see and make colours, and that the pursuit of that science and technology has been one of the shaping forces around human history.

Andrea Macdonald, founder ideaXme: [00:12:56] In 2015, you wrote an article that was read by 38 million people across the world. That article focused on the many subjects covered in your new book. Could you talk about that article?

The Science Of Why No One Agreed On The Colour Of The Dress

Credit: WIRED magazine.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:13:19] Sure. That was an article about The Dress. You might remember this. There was a meme on the Internet where people looked at a picture of a dress, of a woman wearing a dress and assorted themselves into two groups. Some people saw the dress as being white with brown trim and other people saw it as being blue with black trim. And that doesn’t seem like that big a deal. But the people so adhered to the way they saw that dress that it became like the red and blue divisions in the United States. It became like the Wars of the Roses with colours. It was astonishing the degree to which people, once they saw it, stuck to that belief and then thought that anybody who saw it the other way was crazy. And this was before, when people were still using the Internet for real stupid stuff, instead of overthrowing governments.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:14:30] I’m a writer. I’ve been an editor and a journalist at WIRED magazine in the USA for a long time. In our newsroom, it became very clear, almost immediately, to us that that was a science story. I had spent, before I came to WIRED, in the early 2000s, a year at MIT, Massachusetts Institute of Technology as a journalism fellow there (Knight Science Journalism Fellow, MIT). And one of the things that I looked at was the science of colour, of how colour worked both in the world around us, the photons and wavelengths bouncing off of surfaces and then coming into our eyes, interacting with receptors on the back of our eyeballs and then getting shaped into a perception of colour in our brains. And I spent about a year reading about that, for reasons we can talk about.

So, on discovering this story, I had some people to call. I wrote the article to explain why it would be possible that something that we might, as humans intuit was an objective facet of the world was in fact really a philosophical qualia, which is to say objects have colours, things have colours, and then we perceive them.

It is a really complicated and almost provocative thing to say and explain why different people would see the same thing as having different colours. That became one of the foundational tenets of the book — colour is an interaction really between our physiology and our neuropsychology and the basic chemistry and physics of the world.

Andrea Macdonald, founder ideaXme: [00:16:07] Could you explain a little bit more about why people saw and perceived a different colour? A neuroscientist called Anya Hurlbert, talks of this incident (different perceptions of The Dress) and said that it shows how different we all are to each other and how differently human brains work. Could you go into the science of why people perceived The Dress differently?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:17:14] Not only did this picture of The Dress kind of shake up the Internet for a day. It really shook up the people who study colour and the perception of colour in the brain because it called into question a lot of fundamental things that they thought they understood. And it turned out that they didn’t, or at least they didn’t understand all of it.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:17:34] One of the things that our brains do for us is a principle called colour constancy. That is, when we subtract the colour of the light shining onto something from the colour of the object. So, here’s an example. If you see a picture of an egg that we would see under a red light. Our brains don’t tell us: Oh, my gosh, it’s a red egg! Our brains say: Well, that’s an egg. And there’s obviously red light on it.

Nobody’s really sure how we do that. It might be because we remember what colour eggs are in reality in our brains. It might be because we compare the colour that we’re seeing in front of us to the colour, something familiar. There’s a lot of hypotheses about how this works.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:18:17] But what happened with The Dress was essentially a failure of colour constancy in a very specific way. And the theory is that one of the ways that people evaluate the colour of something is by taking a very good, educated guess as to what colour the daylight is on it.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:18:36] There are a bunch of maps of all the colours that a human being can see and all the colours that exist. One of those maps is sort of a horseshoe shaped thing. It’s put out by the French standards setting organisation that works with colours — The International Commission on Illumination.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:18:52] There’s a specific axis across this map of colours called the daylight axis. And it’s the colours that you would think of as being early morning pinkish, to midday clear bright white, late in the afternoon, bluish indigo and then the colours of sunset. And when people looked at the picture of The Dress, their brains, this is the going hypothesis, made an assumption as to what time of day it was.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:19:24] It may also be influenced by your experience. That is, if you were the kind of person for whatever reason, maybe because you’re a night-time person who likes to stay up all night and doesn’t like being awake in the day or vice versa. If you thought that it was a picture of a dress in shadow late in the day when the Sun was low, then you thought, oh, well, the colour of that light was sort of darkish, shaded blue. And so that’s the colour of the light shining on it. And you thought the dress was white.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:19:52] It wasn’t a professional picture. Somebody just shot an image on a mobile phone. If you thought that it was clear, bright, white, midday sunlight shining on that dress, then you thought that the dress was the thing conveying the sense of blue and the light was white.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:20:09] And our brains, when presented with that, with that chromatic illusion, with an illusion of colour sorted immediately into a sort of biphasic distribution. We chose one or the other. At least, that’s what happened initially with The Dress. Some subsequent studies said that didn’t happen at all.

Andrea Macdonald, founder ideaXme: [00:20:29] So, the brain eliminates chromatic bias?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:20:33] Essentially, yes. If you’ve ever messed around with digital cameras, the thing about white balance, when we have to tell the camera, especially video cameras to do this. We have to tell the camera: Ok, I want you to pretend this is white. Whatever thing I’m showing you, pretend that’s white and adjust all the other colours you’re seeing to that.

So, our brains do something similar. We take a sort of standard. We set a standard for what the colour of the world around us is. And then we assume every colour exists in that context. Because, of course, what we’re seeing is an illuminated world, lit by more than a sextillion photons, every second hitting every square meter of the day lit part of the planet and bouncing off, or sometimes bouncing through and then bouncing off those surfaces and then coming back into our eye.

There’s an interaction that happens outside our brains, that our brains have to make sense of. And in this case, our brains didn’t make sense of it at all, partially because we were seeing stuff on a screen most of the time instead of as a flat colour around us. So, the screen was emitting colour, instead of just reflecting those colours. And because we’re not really that good sometimes at seeing those daylight biases.

Illusions Of Colour

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:21:36] The really weird thing about it also is that, you’ve probably seen illusions of form, illusions of shape. The silly little illusions that show that our brain processes information in weird, unexpected ways, but with those illusions of form, our brains tend to switch back and forth. You tend to see the duck or the rabbit or the duck or the rabbit back and forth. With these illusions of colour, apparently our brains just fix into it.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:22:11] And so trying to understand why that was, really did take a lot of time and effort by people studying that dress, including Anya Hurlbert, who later actually got The Dress, the actual dress, the real thing, and set it up to be viewed. She created these displays of it where she put it in a gallery and lit it cleverly with LED lights so she could very carefully control what actual light was illuminating from The Dress. So, it would look like it was white Light, but it wasn’t. It was what’s called a metamor, a colour of light that our eyes see as being one colour, even if it’s not a pure wavelength.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:22:44] And by tuning those lights, she could make people see that dress almost any colour that she wanted, not just white or blue, but a whole bunch of other colours.

So What Colour Is It Really?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:22:53] When you ask these scientists, as I did: So, what colour is it really? Like, come on. I mean, it’s kind of real colour. What colour is it, really?

And they said: You sweet, poor, naive boy, you can call it whatever you want. There’s no such thing as colour! It all gets assembled in our brains, which is a concept that when you internalize it will make it so you just can’t sleep at night.

Andrea Macdonald, founder ideaXme: [00:23:19] And in describing colour, your book also goes into the realm of linguistics. There is an interesting study done by Paul Kay and Brent Berlin. Could you talk a little bit about that and the significance it?

Linguistics And Colour

Credit: Author, Adam Rogers.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:23:39] Berlin and Kay’s work has been foundational. And this is an interesting issue because in linguistics, in a lot of cases, the linguists, especially the foundational ones, are using colour as a tool to understand language. And then the more they understand the language, it turns out they can use that to understand colour. So, there’s this really interesting back and forth dynamic that existed even before Berlin’s and Kay’s work.

[00:24:00] Before he became British prime minister, Gladstone wrote a book that was a translation of the works of Homer. And one of the things that he said, was he had trouble figuring out how Homer was using terms to describe colour. There’s the famous example of the wine dark sea as something that comes up a lot in the Homeric epics, The Odyssey and Iliad.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:24:23] Gladstone said: I don’t know what that means. I don’t know what colour word he’s using there. The seas don’t look like wine. They’re not dark. I don’t get it. And that led to some speculation.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:24:34] Some of the German romantic poets and philosophers in later centuries thought, well, maybe the ancient Greeks actually couldn’t see the colour blue. The way that our eyes perceive colour is if you have colour vision, you see these sort of wide swaths of colour organised by specific kinds of receptors in our eyes. But they’re organised around essentially the colours, blue, green and red. So, the idea that the Greeks were somehow different to later humans, is a shocking one. But it wasn’t so much the idea that their physiology was different, perhaps, but somehow that culturally they weren’t able to see blue. But the question then became, well, maybe it was just that they didn’t have a word for it. And that led into a line of thought in linguistics that has come to be called linguistic relativism. And it’s really most associated with the sort of self-taught linguistics.

Sapir-Whorf Hypothesis

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:25:29] The Sapir-Whorf hypothesis, or whorfianism, is that if you don’t have a word for something, then you can’t really think of it. And this has been hotly argued in philosophy and linguistics for decades, if not centuries. The philosopher David Hume asked about it, whether people could conceive of an idea that they had never come across, seen before. Hume used colour as an example, a missing shade of blue. He said that if you showed a person an array of blue from light to dark, you know, a bunch of different blue shades and had one missing. Could they imagine the one that wasn’t there if they’d never seen before?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:26:01] His conclusion was unlike almost any other kind of concept. The colour was a sort of special case that, yes, people could conceive of a shade of blue they’d never seen before. So, Berlin and Kay, linguists who both realized that in the languages that they studied, they were both native English speakers, but they were studying other languages too, and they were having an easier time learning some of these other languages, partially because they had fewer what are called basic colour terms.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:26:24] So you and I might talk about colours like turquoise or indigo. But those are all descriptions of objects that have a particular colour. If we talk about gold, for example. We talk about the colour of the earrings that you’re wearing. We’re talking about the material almost and using that as a proxy to say what colour they are.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:26:49] But blue, red or yellow that are only about the colours themselves. The only metaphor that they have is for the colour. They don’t mean anything else. We call those basic colour terms. Berlin and Kay wanted to understand why some languages had different numbers of those words and why in which languages.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:27:10] So they did a bunch of studies where they interviewed people who were first bilingual with English and then other languages and then eventually native speakers who weren’t bilingual and showed them a card with a bunch of colours on it and said: OK, what’s that? What do you call that one? And if they had and looked at whether they had a word for it or didn’t and what they thought that they found was a pattern, which was that as languages evolved and developed, and that’s a pretty fraught way to put this, that has some racial implications to it, that first language just started with black and white. And then if they had another colour term, it would be red. And then if they had another colour term, it would probably be in the blue or purple or green world, and then it would be purple and so on.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:27:53] And they thought that every language evolved in that certain order. And that idea came in for a lot of criticism immediately. People said, for example: Most of the folks interviewed were bilingual and most spoke English.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:28:03] What does it mean to say language is evolving or developed? Does it mean it’s older? Or are some languages somehow better than others? Of course, they aren’t. They just have to function as ways to communicate.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:28:15] And it also led do a bunch of evolutionary pseudo-evolutionary questions like: Why do people need to see colours? Why do we have words for some things and not others?

So, you’ve probably heard of hypotheses like, oh, well, you have to be able to see the colour of ripe fruit against the green background of a forest, or there’s an evolutionary advantage conferred by being able to infer emotional state of a person you’re talking to, based on whether they’re blushing or not. These are some stories that evolutionary psychologists tell each other. There’s not great evidence for most of them.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:28:47] What Berlin and Kay eventually did is send informants out to a bunch of different countries and interviewed a selection of different people in the places that they lived in and interviewing them in their own languages. And what they found is that languages evolve.

We have words for light and dark colours, and then they would sort of add to them based on a feature that there are a lot of definitions for this word, based on salience, based on what they needed to be able to talk about in everyday language. But this idea that if you don’t have a word for something, then you can’t think about it still persists in linguistics, of course.

This premise is probably not true, because later studies have shown that you can show people the same array of colours, and even if they don’t have a word for it, they’ll recognize a difference. Sometimes they’ll have different words for it, even if they live right next door to each other.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:29:42] There are some edge cases here. One of my favourite examples of this is that in English we have one basic colour term for blue. Russian has two basic colour terms for blue. There’s one for light blue and one for dark blue. I won’t pronounce them right, but for light blue it is голубой, goluboy and dark blue it is синий, siniy.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:29:57] There’s this experiment. I love this test, where they showed both researchers showed both Russian native speakers and English native speakers what’s called the triangle test. You show two examples, one thing and then one example of another.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:30:10] And so they showed them two examples — one of the blue colours is either light blue or dark blue. And then they would bring in a third. And the volunteer had to say whether it was the same as, or different to the two, that they already had seen. Russian native speakers could do that faster than English speakers. The idea being, if your brain has developed with the idea of two basic colour terms for blue instead of one, that somehow you’re more receptive. You can see blues more quickly than somebody who hasn’t. This has fascinating implications.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:30:44] I think more recent work suggests that, in fact, even within normal variation, people who have normal colour vision, all see the same range of colours. Sometimes they have words for them, sometimes they don’t. In the same way that if when you sniff a glass of wine. I wrote a book about science of booze (Proof: The Science of Booze), too. And when you have a glass of wine, probably you and I are smelling the same glass. We might say that the wine tastes of blackberries. We’re smelling the same glass of wine, of course, and can detect the same things. The Sommelier would probably have more words to describe that glass of wine. Similarly, you might have more words for those colours.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:31:21] There’s more recent work that I like a lot. One of the authors is a researcher called Bevil Conway, a neuroscientist and artist, and an expert in colour at the National Institutes of Health here in the USA. He is like a guru for me on this stuff. His work tries to reproduce what Berlin and Kay had done, but using information theory to try to figure out, well, how many words does it take somebody in a given language to tell me which colour chip to pick up? If we play a game where I say: Ok, here’s the colour chip that I want you to pick up, and describe it using any word I can. They found that what an artist would call warmer colours — the reds, the oranges, the yellows were easier to describe had more information contained in them. That’s a pretty interesting difference. That is a different way, a different slice of the same problem. What does salience mean? Which colours are more important to which cultures and why?

Andrea Macdonald, founder ideaXme: [00:32:18] And we talk about the physicality of colours and how we as humans have created all these different colours through history and how that has been related to the discovery of new elements? If you could start with talking a little of Sir Isaac Newton’s discoveries in this area.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:32:44] I will say that in the book I did not want to start with Isaac Newton only because so many books do. And his work relied so heavily on the researchers who came before him, as all scientists do. He famously made this joke. He was mostly trying to insult his competitor, Hooke, saying that he had stood on the shoulders of giants because he was really short and he was trying to insult Robert Hooke.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:33:11] But in this case, he really was he was standing on the shoulders of about a thousand years of Arab scientists who were translating and correcting the terrible work that the Greeks and Romans had done on colour because they really didn’t understand the science.

Many of the Arabs over the course of about the year, two hundred through to about the twelve hundred were experimentalists and trying to figure out fundamentally why light didn’t just reflect off of things, but sometimes refracted in a way it would go through something and bend. And how that changed the way that we perceived colours looking at, for example, trying to figure out what a rainbow was and how colours changed in that range when you look at a rainbow, how, why light could be one colour and then another colour and how that related to the pigments that they were using every day as dyes and as paints. Because, of course, human beings throughout human history have taken natural materials and turned them into the stuff that we could use to give colours to surfaces.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:34:19] We have been making colours from early history. Artefacts were found in a cave called Blombos in South Africa, I think that it was 80,000 years old. Abalone shells with stones inside them were found that were used to grind ochre, iron oxide, like the red earth you see in South American desert, Southwestern USA desert, or on Mars to turn it into a red pigment that could have been used to decorate a person’s body or a wall of a cave.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:34:50] By the time Newton was doing the optical experiments, he knew that there were these colours, coloured stuff that people could make. And you can mix that stuff together and apparently create (have) a different colour. And he knew that light shining through these new optical technologies called prisms will break into other colours that the light didn’t have. So, in 1665, in a way that all of us can unfortunately probably relate to now, is put on work from home from due to a pandemic. In his case, it was the plague. He goes to his mom’s house, and turned a study upstairs into his office, as so many people did in the past year.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:35:39] There he started to play around with light and experiment with his own eyes. He stuck, needles into his own eyes to see if he could make himself see colours and light. He stared at the sun for too long and that messed him up for a while. He had to stay in the dark room for a week until he felt better.

He Has Somehow Bent Light

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:35:52] But one of the experiments that he did were when he closed the shutters, blocking off all the light of day and then poked a little hole in one of the shutters. He sourced two prisms. Optical technology was just beginning. He put one prism in the way of the beam of white light that’s coming in from outside of sunlight and on the opposite wall it broke into a strip of multiple colours of what he would have seen as a rainbow, and he named it the spectrum. And what he then learns is that if he’s able to put another prism in the way of one of those colours it doesn’t break up any further. It stays that colour, so something has happened. He’s somehow bent light and this was the math that he was able to figure out, that when you interrupt the direction that white light is travelling in, something changes also about what colour it is.

Andrea Macdonald, founder ideaXme: [00:36:53] You tried to recreate that experiment.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:37:00] I was about to say, it’s a lot harder than I just made it sound. I bought a couple prisms to try to do it myself. It’s really hard. It’s really hard to do, especially with the distance he was doing it. People don’t realize, it was about 20 feet. He succeeded creating a big spread of that initial spectrum. I know that I couldn’t do it. I could get the first one. I couldn’t break it up in the second one. So clearly, Isaac Newton was a better scientist than I am. I don’t know that there was ever any question of that. I tried but it didn’t work for me. It worked for him.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:37:32] So why is that interesting? Well, what he’s figured out is that in the whiteish or yellowish sunlight that people perceive, the colours that we see are somehow hidden there. And he wraps those into a circle, invents the colour purple to join the violet at one end with the red at the other, and then invents the colour, but uses the colour purple as a name. That’s what connects the two.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:37:57] This gives rise to the idea of a scientific and objective way to map colours into a space. Other people had been trying to do this for thousands of years and he got the first kind of mathematical version of that. And so that sets off many more researchers trying to figure out, how does the eye see those colours and what are those colours made of?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:38:17] As I mentioned, Newton was doing that in the sixteen hundreds. By the time you get into the middle, seventeen hundreds and the late seventies, the kind of early industrial revolution, people were also trying to find more and more natural materials, synthetic ones to make into new colours. And that was to be the real hallmark of the later industrial revolution and certainly in the 20th century of an explosion in the materials that people could use to replicate the colours that they saw in the natural world around them.

From Lead White To Titanium Dioxide

Andrea Macdonald, founder ideaXme: [00:38:59] Could you talk to us about the development of some of those colours, for example, something as simple as the colour white?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:39:08] The famous one, of course is Perkin’s mauve (one of the first synthetic dyes, 1856), a pinkish colour, which was accidentally developed. But I actually became obsessed with, and that became part of my journey to writing his book, I got interested in the colour white because of a particular pigment called titanium dioxide, which is a modern pigment.

It was invented in the early 20th century. It is ubiquitous in the human-built environment. If you look around the room that you’re in right now, any surface that’s artificially coloured, that’s coloured by human hands probably has titanium dioxide in it.

Andrea Macdonald, founder ideaXme: [00:39:49] And it is even in food, isn’t it?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:39:49] Yeah, it is. It’s because it’s very bright and very opaque and very inert. You’ll find it in plastics and in paper and in paint and sometimes even in the white on powdered donuts. It used to be in the filling of Oreo cookies. I don’t think they use it there anymore. It is in cosmetics. It’s all over the place. And I became really fascinated by why and how that should be.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:40:13] Titanium dioxide was a replacement. And in fact, for thousands of years before that the white stuff was almost always led white. It was made out of lead and probably invented by the ancient Egyptians.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:40:27] Basically, you take lead, pure lead and you cook it in vinegar. The vinegar, the acetic acid creates a chemical reaction with the outside of the lead. And it produces this white powder. It was really useful. It was the way you made white paint and other paints. It’s what you would see in almost every pigment for thousands of years. It’s also as toxic as lead is.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:40:51] The people who made white lead paint became very sick. The people who used it also became very sick. If you consumed it, you would be very sick.

Andrea Macdonald, founder ideaXme: [00:41:01] Really fascinating to discover from your book that we knew, even as far back as in Roman times, that lead white paint was bad for us, yet we continued to use it.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:41:15] Yes, even Pliny, wrong about so much, in ancient Rome wrote instructing people not to use lead as a vessel to make wine. There were warnings that women who were wearing lead paint cosmetics shouldn’t wear them to the spa bath because there was sulphur in that water. Sulphur interacts with lead and it turns black. Women who used lead white cosmetics lost their hair. A lot of the pictures that you see of Queen Elizabeth, the kind of famous one where she’s got the white pancake makeup and her bangs cut back, was possibly a receding hairline as a result of lead foundation.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:41:58] Benjamin Franklin wrote about how toxic lead was and that the lead rooftops that they were using in the colonies were leaching lead from rainwater into the rainwater that people were drinking.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:42:14] People knew it was toxic, but there was no replacement. And there was a huge business in white paint.

In the early 20th century when an engineer and metallurgist chemist named Dr. Auguste J. Rossi discovered an alternative when he was trying to figure out in a lab in Niagara Falls using the power of the electricity to do some chemistry. He really understood the metallurgy of the titanium element, very common that had been discovered about a hundred years previous. And he realized that as an intermediate step in the process he was trying to come up with, he had produced this bright white powder and he knew that there was a need for a replacement pigment, that there was a huge market for this stuff.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:42:55] He famously dipped his finger in some salad oil and then mixed it with the white pigment and brushed it across a piece of paper and realized that he had a new white. And this would become the defining white pigment of the 20th century, starting about nineteen twenty. This was the thing that changed the brightness of every colour that people saw.

Andrea Macdonald, founder ideaXme: [00:43:13] And they added sulphuric acid to titanium oxide to make paint?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:43:18] Yeah. The original process required sulphuric acid, which was dirty and gross and hard to do. There was a replacement process, still used today that requires Chlorine gas, also highly toxic.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:43:36] I have been to one of the facilities that makes this stuff today. It’s an18 billion dollar a year business. There were giant pipes to move chlorine gas. And what they said about the safety of it, was that you never want to see chlorine gas. If you see it, you’re dead. One of the guys that I talked to said he had seen it once, due to witnessing some catastrophic event where this stuff had been present.

Andrea Macdonald ,founder ideaXme: [00:44:08] And although, titanium dioxide is still considered safe, the EU have recently put rules in place to ensure that labelling of products that contain it are more detailed. Could you talk about that?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:44:25] Like so many of the things when we talk about carcinogens, because that’s what’s at issue here. That’s a complicated issue. But there’s a sense, there’s some science, it’s preliminary that says that particularly titanium dioxide nanoparticles are worth evaluating further. The pigments have some of that, but the pigments are mostly the micron scale because the size of a pigment particle is really one of the things that gives it its colour when other features that the nanoparticles might be like other nanoparticles, carcinogenic.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:45:03] The EU has issued some warnings in that regard about titanium dioxide, broadly. But a lot of the studies are actually on inhalation of the powdered titanium dioxide, which isn’t something that most people ever come into contact with. You come into contact with titanium dioxide mixed into a paint or embedded into a plastic. So, we very rarely breathe in titanium dioxide dust.

I’m not even sure where you would encounter it. And even if you do, it’s not usually nanoparticles and it’s not clear whether those could mess up your lungs in an inhalation kind of way, or whether there’s lung cancer consequence.

The science there isn’t finished. It needs to be done. And it’s confounded by the fact that the titanium dioxide is embedded in the industrial processes of so many different businesses that trying to get just the nano scale particles out would be almost impossible. You’d have to remake entire supply chains, which you would want to do if it was if the danger was great enough, obviously. The business fights against that. And different scientists are on different sides of this, too. So, it’s still kind of a thing in play.

Andrea Macdonald, founder ideaXme: [00:46:19] I understand it doesn’t just exist in its white physical state. It’s also used to brighten up other colours?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:46:26] That’s right. That’s part of the thing that makes it so useful. You’ll find it in in a red paint or a blue paint or whatever shade because what it does is confers opacity and brightness. So, brightness is the thing that makes the colour “really pop”. There’s a story. It might be apocryphal, but I like the story a lot. In the days of the Cold War, there was more titanium dioxide available in the West than there was to the to Russia in the countries associated with the USSR.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:46:57] And so, like in Berlin, when it was a divided city in the West, the colours of the paint were much brighter because they contain titanium dioxide. And so when you went over the Wall, the colours in the East were dingy by comparison to the West. They weren’t painted as often, but you sort of got these more muted and more pastel colours on the on the east side of the city.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:47:19] But even now, you’ll find it in paints not just for brightness, but also opacity. It lets less light through, which means that you need less of it to cover a surface.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:47:44] Your bathroom and medicine cabinet — every pill, every capsule, every cream, will have titanium dioxide as an ingredient.

Andrea Macdonald, founder ideaXme: [00:48:01] Can we talk of the whitest white on Earth and the laser technology that was used to try to find out why a beetle shell was so white?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:48:13] I’m not even sure it counts as the whitest white anymore. But when I was writing the book it was. There’s a particular kind of beetle. Beetles have these remarkable shells because of the structure of a material called Titan, same stuff of lobster shells.

Adam Rogers, Senior Correspondent WIRED magazine and author: [00:48:59] You can have a structural colour instead of a pigment. So, you can find beetles that look like gold and metal or that sort of iridescent, that look different colours, depending on what angle. And there’s one called Cyphochilus.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:49:17] That has an extraordinarily bright white shell and nobody really knew why until some researchers tried to figure it out. The way they figured it out was they took pieces of the shell and mounted them on a little stand and then shined lasers through them with sort of a screen around the pieces of shell, so that when the shell diffracted the laser they could see shadows on the walls and try to understand how the material inside the shell was organized.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:49:45] It turns out that the white has a very specific kind of lack of structure and lack of organization.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:50:04] And that holds true for things like milk and for things like clouds and for things like foam. All the stuff that you can think of that are kind of reference, quality, objective, white, all have that same sort of pattern of internal structure organization. And this beetle had it in like sort of the perfect amount to make this bright, white, very reflective, very, very white shell.

[00:50:28] In fact, some researchers tried to then replicate that. They used an electro-spinning process, which is actually the same process that’s used to make face masks, the surgical face masks, personal protective equipment that have gotten so familiar to people where you have like two poles for electricity, have a positive and a negative, and you kind of extrude this material with the exact right distance between the poles on a spinning drum. And when it came out, it organized itself. The biopolymer, basically a plastic organized itself, just like the beetle shell did. And they got the same kind of white, which could have potential uses for fabric or textile at some point in the future. I don’t think they’ve really commercialized the process yet.

Perceiving Colours Without Eyes

Andrea Macdonald, founder ideaXme: [00:51:12] We’ve spoken about perceiving colour through the eyes. Could you talk about the halobacteria that perceives colour, although of course it has no eyes?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:51:24] It’s a complicated question because we get very used to the idea that, like, oh, we have eyes and so therefore we see colours. But of course, different animals with eyes see colours very differently than we do. I can name example after example, but the classic ones are, for example, a honeybee has eyes that are built sort of differently than ours, but they have many of the same kind of photoreceptors, but they’re tuned to an almost entirely different set of colours.

Halobacteria

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:51:56] Where we might see broadly red, green, blue, the honeybee will see green, blue, ultraviolet as it looks out at the world. That is the same world that we see because their eyes are pretty good and see a whole different set of colours.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:52:13] You can kind of get a hint of it. If you look at flowers at the end of the day when the sun is low. They look sort of luminous and incredibly beautiful. In the magic hour, as a filmmaker cinematographer might say, you’re getting a little bit more of the ultraviolet there. That’s what the honey bee lives in every day. Or the mantis shrimp with 12 different photoreceptors in its eyes, instead of just the three that we have for colour, sees a whole different world than we do.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:52:37] That’s even true of microorganisms that don’t have eyes at all such as Halobacteria, which despite their name, are not bacteria. They’re from a whole different kingdom on the tree of life than we are.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:52:56] They predate human life. They are what are called extremophiles, so they live in environments that other things can’t live in, super salty or super-hot or super cold. Halobacteria live in these really, really salt like salt ponds or brine pools.

Adam Rogers, Senior Correspondent WIRED magazine and author: [00:53:19] They swim toward orangish light and away from blueish light. I may have that reversed. And so the question is: How do they do that and why? They don’t have eyes. They don’t they don’t need to pick out ripe fruit against the background of trees. What’s the point of that? And how do they do that? It’s even more important because you think, well, what are the receptors, what are the molecules they’re using that photons are interacting with somehow and changing their behaviours?

Adam Rogers, Senior Correspondent WIRED magazine and author: [00:53:50] So it was probably true is that bright light suggests to them, open water and so they want to avoid that because they can get preyed upon, something else will try to eat them. And darker light means that they might be able to find food, or they can hide. So, it’s another evolutionary” just so” story. Nobody can interview Halobacteria and ask them what they think. But the actual photoreceptor, the molecule that they use to do that, that interacts with photons of different energy levels or wavelength different wavelengths of light, which as a physicist is two ways of talking about the same thing in physics.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:54:28] In many respects, looks exactly like the ones that are in the back of our eyeballs. It’s a protein that sits on the inside and outside of cell. It crosses the cell membrane seven times and it makes a sort of cage and it has another bit of itself called a chromophore inside it. And the way that you shape that protein can change the amount of energy that it takes for the orbit inside to go from being dogleg shape to being straight. And so depending on how much energy it takes, that’s how many of the photons can come into it. And that triggers a whole set of other cellular signals that the modifies halobacteria’s behaviour — go that way, or no go the other way. And then for us, lets us develop a picture of colour in our brains.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:55:19] So the question we ask is: Is the way humans see colour billions of years old?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:55:21] One answer would be, well, yeah, obviously it is. The molecule is structured the same way. That’s clearly the way that living things can perceive different wavelengths of light or photons of different energies. But the weird thing is that the halobacteria’s amino acids that make up that protein, the individual building blocks of the protein are different than ours.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:55:49] The shape of the protein is the same. I think I say this in the book, it’s like building the same spaceship with different Legos so you get the same shape, or making the same cake with different ingredients. I guess you get roughly the same end product, but with different building blocks. So maybe ours evolved from theirs. Maybe the living things that we know on Earth have evolved their colour receptors from that.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:56:11] Or maybe just there’s just one really good way to perceive colour. That evolution just sort of figures out the solution to again and again. Does it once, stops there, starts again, and then figure out how to perceive colour again, because it’s just so useful to be able to perceive different wavelengths of light in the world around us.

Andrea Macdonald founder ideaXme: [00:56:31] And it converts what it perceives and to energy and information?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:56:40] Right. Well, so then the question is, what’s the halobacteria actually doing? And then studying them over decades, the initial idea was where they must have a pigment in their eye. That’s what a photo receptor is. It is essentially a pigment. It reflects some light and it absorbs others. And the absorption of that light is what starts this other signal. It turned out what they were doing was actually using those photoreceptors that I mentioned. Some of them they’re using the first ones they discovered not to regulate that behaviour, to see light. They’re of course not really seeing because they don’t have eyes.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:57:10] They are doing this to get nutrition, to get energy, almost a kind of early version of photosynthesis as a proton pump, moving energy through their cells. And in fact, they had whole other pigments that they were using to do the behavioural stuff to move toward, or away from different kinds of light. The parallel I tried to make was they were first using it for energy and then using it to get information about their environment.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:57:41] So plants use light for energy. We use it for information. But does this kind of progression suggest some final evolutionary goal here? And of course, there isn’t. But it suggests that all of the different uses and meanings of light and colour, that’s both information and power.

Inducing The Human Brain To Perceive Colour

Andrea Macdonald, founder ideaXme: [00:58:02] Can we just go briefly back to humans. Of course, we perceive colour through our eyes, but there was a fairly recent experiment where neuroscientists delve into the human brain and were able to make that person see colour. Can you talk about that?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:58:26] There’s not a lot of work in this area, but of course, there’s a great deal of interest in what are now called brain computer interfaces. This idea that you can pick an array of electrodes in some form and then attach it directly to a brain, to a person’s brain. You probably want it about here (points to visual cortex) because this is the visual cortex is and then pick up the electrochemical signals of what the brain does when it’s at work and then translate those signals into what the brain is thinking. And then get those signals into a computer and get the computer to do something, and you’d like that to be an input and an output. So, use it to control a computer as an interface, or control a prosthetic, or even talk directly to another person who had a similar implant. And then also to try to put that information in to say: Oh, I need to remember my address book instead of looking at my phone, I could have it zapped directly into my brain, I suppose, or something like that.

Adam Rogers, Senior Correspondent WIRED magazine and author: [00:59:25] This is really hard to do, not least because nobody really understands what the brain is doing. Nobody really knows how to. There are a lot of good ideas about how the brain works, but nobody really can say: Oh, well, we get an individual electrical zap change in an action potential along a neuron, talking to other neurons, sending chemicals to the other ones to tell them to do the same thing or a different thing. And what that translates to in terms of the thought.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [00:59:47] But over the years, there have been opportunities to attach these panels of electrodes to human brains and try to figure out what’s going on in that brain. Usually, we do that because we’re trying to do some sort of medical procedure. Obviously, this a big deal. It’s brain surgery. You’re putting electrodes on top of brain.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:00:06] Most of this work is in non-human primates, or in other kinds of animals. There was a paper published out of Baylor University, Texas more than a decade ago where neurosurgeons were working with a person who had a very bad seizure disorder. A seizure is the electricity in the brain not being controlled, sort of starts to operate at random, and that can cause all kinds of problems.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:00:38] So they were going to try to find the part of the brain that was having those seizures, having that uncontrolled activity and do something to probably try to take it out surgically. But first, you have to find it. The way you find it is via a panel of electrodes.

Adam Rogers, Senior Correspondent WIRED magazine and author: [01:00:58] But as long as you’re in there, you might try some stuff. And so they got interested in trying to put in and trying to figure out what happened when a person sees colours and then they try to reproduce that signal and put it back in.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:01:12] The first thing they did was they showed the person a lot of black and white and colour images. They showed pictures in black and white and then showed pictures in colour. And the person’s brain sort of lit up at the blue of the Lone Ranger shirt, one of the pictures.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:01:40] But then they tried this thing where they put in signals as well. And the person, because they were awake for this, could say what they were seeing while it was going on. The person reported being able to see, first of all, what are called phosphenes, the little flashes of light and electric blue sparks. He saw that colour. They were able to induce not just phosphenes, but a specific colour in the brain.

And they don’t really know why that colour and not another one. But it does give a hint at least of what a brain computer interface could convey — images that you could put in some if you had a sophisticated enough set of electrodes and understood enough about the brain and enough about how to put in signals. That you could actually induce colours in specific shapes, which is really all we’re ever seeing is colour and shape with some dimensionality,

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:02:44] If you can induce enough of that, you could maybe induce images. That’s what it presages. That’s a long way off. There’s a lot to figure out until then. But I’m still struck by the fact how much of colour research runs up against rocky shoals when it tries to think about or deal with the colours blue and green.

The gru region of the spectrum are really troubling for the human eye and brain for a lot of different reasons. But, of course, it would have to be just as just as David Hume had written in the seventeen hundreds, I guess, about the missing shade of blue here, where these neuroscientists in the late 20th century, early 21st introducing a new shade of blue that the person had never seen before directly into a human being’s brain. I like the parallelism.

Michael Foshey and Liang Shi

Andrea Macdonald founder ideaXme: [01:03:30] Can we talk about exponential technology and how that is advancing both our understanding of colour and helping us to produce new colours, maybe beginning with Michael Foshey’s work at M.I.T?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:03:47] You have Foshey and Shi at MIT, both computer scientists worked on the project that you mentioned. And I want to make sure that they both get credit for this because they both worked on this project together. They were trying to make three dimensional objects with colour is where this started. So, using a 3-D, using a colour 3-D printer to try to reproduce chromatically complex surfaces like wood, let’s say, which has a bunch of different colours all wrapped up with each other in different ways of interacting with light, specular reflective sheen coming off the surface.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:04:19] What they hit upon was an experiment to try to basically forge paintings and not for crime reasons, but that they wanted to try to make reproductions, a posters of paintings, that you put up in your dorm room, school.

They wanted it to have that property of colour constancy that I was talking about earlier with The Dress, where they wanted it to change under different colours of light, the same way that the original would change.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:04:51] One way that you can tell something is a copy. If you get a poster, that poster of Gustav Klimt’s The Kiss that many college kids used to put up in their dorm room, you would know that it wasn’t the original Klimt, because if you shined a red light on the original Klimt, it would look one way. And if you shine the same red light on your poster it would look another way. And obviously that’s the poster.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:05:10] So, they wanted to see if they could use this 3-D printing technology to create replicas, reproductions of paintings that would react the same way under different colours of light that would do colour constant the same way. And the idea that you could learn something about colour constancy and also about 3-D printing.

[01:05:27] So they built this very sophisticated machine learning algorithm where they would show their 3-D printer, the computer that controls their 3D printer a bunch of different colours on a tiny little chip and tell it to go through its entire array of possible pigments that it could print with until it could reproduce that colour under different kinds of light that would show it that colour under different lighting. And in order to do it, they had to create their own custom built 3-D printer. Most reproductions of colour, if you’re thinking about a magazine page, let’s say printed magazines use four colours of ink for primary colours. They call them CMYK, but that’s cyan, magenta, yellow and the k is for black. The white is usually the white of the paper that it’s printed on.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:06:17] And when those are for reflective surfaces, those are called subtractive colours. When they overlap, they create all the other colours that you might be able to see a screen like the one you’re looking at me on right now tends to use three different LEDs for each pixel that it generates a red one, a green on blue one, and then it might have white as well, the same way that the same colours that the eye perceives. These are much more focused wavelengths.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:06:46] And then the amount of each of those as they overlap, creates all the colours. So for the primaries that the 3D printer these guys used, they had a red, green, blue, black and white because there was no paper substrate. It was titanium white, in fact. They had a cyan magenta yellow. I think they had an orange and a purple. They ended up with 12 primaries.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:07:15] And the computer using those having access to those families was able to print three dimensional labels. They were still printing a flat thing. But they were able to print things that were under every colour of light, all but indistinguishable from an original. One of their advisers had a partner who was a painter, so they were using that person’s paintings as the original, the substrate, I guess.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:07:37] But the thing that fascinated me about that was, that there are a set of equations called the Kubelka-Munk equations. They’re differential equations that are approximate very close to perfectly, but not perfectly the way light moves through layers through very, very thin surfaces. Essentially, this is a calculus of light because it divides the surface into infinitesimals. And then does the integration through those to say this is the colour that’s going to show. And it’s really important for things like car paint and for house paint, for understanding how colour and the physics of light work. The Kubelka-Munk equations are one of the fundamental things that they teach engineers and colour scientists. But they’re not perfect. One of the things they don’t do that great is figuring out colour constancy. I asked Shi and Foshey: Your computer has solved, has a different solution for Kubelke-Munk, right? I mean, you’ve figured this out. Did you ask it? You have some real fundamental science here.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:08:44] And they said: No, we do not care because it’s a machine learning algorithm. It’s all been in a black box. There’s not really any way to ask it: Can you give us the solutions to the equations?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:09:00] So the thing that really struck me about this was that their computer knows something about colour, that no human knows, some fundamental truth about the science of colour that no human scientist knows. And it just can’t tell us because we have no way of asking it.

Evolution of Colour Science And Exploration Of Space

Andrea Macdonald founder ideaXme: [01:09:19] As we reach out further into space as humans to discover more about ourselves and our planet and who we are, this pushes the envelope in as far as our understanding of colour and application of colour. You mentioned in your book the adaptions to the camera on the Mars Rover. How do you think the science of colour is going to evolve with more complex exploration of space?

The RED Camera

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:09:59] Well, there’s not that much of this in the book, but I do I have a couple of things that I’ve been sort of chewing on about this recently. NASA sent to the International Space Station a very powerful digital camera from a company called Red. The company is actually called Red. They sent this amazing digital camera called the Red Camera into space. This is a really high resolution, wide colour gamut sort of camera that movie makers use.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:10:33] Astronauts take this camera into the Cupola (observatory module) on the space station, which is where they have all these windows and they can look down at the earth. The astronauts have complained afterwards that when they looked at the pictures on any screen, they didn’t see all the same blues and greens that you can see when you look down at the planet. And that’s because the screens that we have, although the new ones are very good — now 8k wide with gamut screens, still aren’t capable of showing all of the colours that the human eye is able to perceive when you look out of that window. And so, there are researchers, engineers and cinematographers now working on screens that have more primary colours in the LEDs to see if this can be solved.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:11:26] So they’re able to show more of the colours that you see out in the world. I think we’ll see the results in the intermediate term, as we spend more and more time sitting in front of screens and consuming sort of colour information from screens, that they’ll be able to show more of the colours and more of the dynamic range, the brightness is from black, black to white, white that are that are proxies in our own minds for emotional content that tell us how to feel about things because of what we’re seeing.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:11:54] And then way beyond that. Already, there are researchers who study exoplanets, planets outside our solar system who use colour to get information about those worlds. So, for example, you can tell from the spectra that an exoplanet emits what is in the atmosphere of those worlds. And maybe if you got a clear enough view whether they have plants or some analogue to plants on those worlds, because chlorophyll on Earth has a very specific emission spectrum.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:12:27] You can see, especially from the infrared, there’s something called the red edge. You can see because they’re green, they’re absorbing a lot of red right there reflecting the green. But they also drop off at a very particular wavelength. And you can see that, where there’s plant coverage on Earth, you can do that same thing with exoplanets.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:12:44] But the thing that I love about this is when we think of colour and what humans and all life on earth that’s ever lived on earth, is evolved under is a very specific emission spectrum, that is the way that our Sun emits light. And we tend to think of the Sun because it’s a sort of white yellow sun, our star, as emitting all of the wavelengths across the electromagnetic spectrum evenly. But it actually doesn’t.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:13:13] There’s some wavelengths that it emits less of than others. And another star, a different star, would have a whole different emission spectrum. So a planet that existed under that star at a different distance, because that makes a difference too would have an entirely different baseline kind of light. Colour would be a different phenomenon on that planet if a human being could ever go there. It’s probably impossible, honestly. But if a human being could ever go there, the way that we would experience colour on that planet would be biased by the way our eyes evolved under the colour that we experience here.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:13:54] So anything that lived on that other planet would have evolved to see colour the way it exists there and would literally see a different world than the one we would see. You can also imagine colour having a whole different meaning there, a whole different use.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:14:09] On Earth, plants typically absorb just about all of the visible light that human beings see, except for the green, which they bounce back to us and we see them as green. But maybe you can imagine a different kind of absorbing pigment that absorbs all of the light, so the plants can be black. Or maybe they would absorb all of the light, but would also be more specular somehow. So, they could be like reflective black, like the most metal plant, or maybe purple.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:14:47] There’s a planetary system called Gliese (Gliese 581, 20.22 light years from Earth) that’s within striking distance of the Earth. I can’t remember how many light years away it is, but it’s a potential (doable) journey, if we have the right rocket. There are a few planets around that star that are rocky like Earth and that are the right size and the right distance that you would think are very promising for the kind of place that could have the sort of life like we have on Earth.

But the thing about the Gliese system is that star periodically emits huge bursts of ultraviolet. And ultraviolet in large doses is really bad for living things on Earth, unless you have the right kind of biology to deal with it. It’s the thing that gives you everything from a terrible sunburn to cancer. So, we would tend to think of a star that admitted regularly huge blast of ultraviolet as essentially being sterilizing that there would be no life there.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:15:41] But you could imagine a biology that had the right kind of the right kind of replicative machinery in the cell to recover from errors introduced by ionizing radiation or the right kind of pigment on skin, they could change colour like an octopus, or a squid does to armour up against ultraviolet when it happened.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:16:02] And for that kind of life in a system like this, maybe periodically what they see is just fireworks. Maybe they see periodically a beautiful light show where every living thing kind of lights up under ultraviolet for a period of time when the star emits these sweeping things that make it possible for life to exist on those worlds.

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:16:19] And that’s an entirely different, colourful universe that requires different kinds of eyes and different kinds of brains and different kinds of physiologies. All of the things that make it possible for us to come to perceive the colour universe around us.

Andrea Macdonald, founder ideaXme: [01:16:36] Before we go, is there anything else that you would like to add which relates to this wonderful book?

Adam Rogers, Senior Correspondent WIRED magazine and author.: [01:16:44] I think that we pretty much ran through it.

I hope to the extent this book has a single take away, that colour is more widely recognised as this amazing interaction between the world that exists outside our heads and the one that exists inside our heads.

To me, colour is as much a thing that has driven economies and historical change as something that sparks the desires of human beings to change their environment. All the things that technology is really about. It is also a way for us to understand the places where ourselves, our minds are affected by it and then impact the world that we live in”.

If you enjoyed this interview check out our interview with BioArtist Amy Karle.

Andrea Macdonald, founder ideaXme.

Find ideaXme across the internet including on iTunes, SoundCloud, Radio Public, TuneIn Radio, I Heart Radio, YouTube, Vimeo, Google Podcasts and more.

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