 is the absorption of the photons, orange is only a small range of photons being reflected. How, so this is, this would be black on red, right, is my understanding correct? Black on red, how do they make this? What pigments do they use to make this color? No idea. Anyone know? So what color is iron? Black. Black, when it's reduced. What color is iron when it's oxidized? So when an iron is oxidized. So what they do is they have a very iron-rich split that's like 10% iron, elementally, which is a lot. It's near-athens and they take it and they fire it in reducing conditions, in other words it's an anoxic. So what color does the iron-rich clay turn? Black. And then they take something and they scrape away everything that's not black. That's why the orange isn't even. And so what you end up with is elementally this and this are indistinguishable. I will get the exact same spectrum because the only difference is oxygen, which I can't measure. So as a consequence you measure this, you measure this, they're like a fingerprint. They match perfectly because it's the same quality, just different oxidizations. By the way, red on black is the opposite. You fire in oxidizing conditions and you try to reduce the interior of the vessel and then you scrape away the oxide here. So that gives you that balance. So this is, I know this because when I was in Greece they had me measure one and I get black here, which tells me that's a lit pigment. It is not a classical Greek space because they only did the oxidization slip. So it's really cool little play of physics. The Myconeans did the same thing. Their black pigment is a reduced iron, which is super interesting. Whereas if you go to Cyprus, you will find them using manganese as a mineral pigment. So whatever you just see iron in the black and small manganese that tells you right away, this is a Myconean or a mainly Greek pop. Like this play of oxidization and iron has been inconsistent in Greece since Greece has been Greece basically. So yeah, but in any case, but that's an example of something you can use as a diagnostic. Now the catch is what I'm doing with that is I'm not, there's not like a specific elemental ratio. If I'm going to be sitting and sourcing, for those of you who are familiar, every time a canel erupts you get this imprint of elements that happens. And it's, you know, a little bit of rubidium, maybe less strontium, ladi, yttrium, tons of zirconium. But the relationship between those elements creates a fingerprint for a specific canel erupture. If a volcano erupts multiple times, like in Alka, you can, in Peru, you can sometimes get a little signature for each eruption. It's a little different. That's obsidian subsourcing. But by and large, the moment you have an eruption, you've got that view. So a very precise measurement for a small group of elements is perfect. What makes it ironic is in the XRF industry, they use a rhodium tube, because rhodium is less likely to be in the sample. If you use a silver tube and you measure a silver object, you're just out of luck. If you have a rhodium tube, you very rarely have it overlap. So the industry went to rhodium tubes. But ironically, rhodium is perfectly situated to excite elements like rubidium, strontium, yttrium, yttrium. So it makes handheld XRF just absolutely perfect for the city, as if it was the entire technology of XRF designed for this one small niche application. But it is true. Like I've talked to Bruce a lot of times, engineering wise, every decision made in the XRF industry is almost as if it was made exclusively for obsidian, because that's the most beneficial market. Most people are frustrated because rubidium and strontium are not important to anyone else besides archaeologists, typically. Although, what we have been doing is we've had a lot of people coming to us asking about plant tracing, like they want to do. So, for example, if I have a toxic element, how do I discover the nutrient uptake pathway? Well, what we found is rubidium and strontium in particular are really good at mapping out where in the soil you get nutrients from. So people are starting to use the same techniques that obsidian is sourcing for nutrient uptake by using rubidium and strontium as sort of like spike tracers. So what you do is just think about your stratigraphy. You have like one thin layer that's super deep that it's just spiked through rubidium, like an unreasonable amount of rubidium, because it's cheap. And then you do that, and then you can actually measure how, what percent of the deep roots are actually going that deep. So you can estimate how, you know, where lead contamination is going to be the most severe based on use of one of these as a tracer. We could do that easily with lead, but you don't want to because that would contaminate the field for generations. So, yeah. Anyway, but long story short, for the Mycenae thing, that's the kind of thing. So with obsidian, we're very fortunate because small traits elements are diagnosed still, but you'll need to be more creative. It'll be how they make the object that actually becomes a stronger tracer to establish those ties. Fortunately, culture, as conservative as both animal and eruption. So once a culture has a specific way of making things, they rarely deviate from it. What about for like fabrics of ceramic material? Like the clay itself. Like if you have like, you know, a broken shirt and you're doing it at the cross. Oh yeah. It's certainly possible. The negative you have. There's actually two big negatives. The first, one of the things that's underappreciated about obsidian source, and the reason it's so eminently sourceable is that you have a point, like a specific place in space and time where the eruption happens. A ceramic comes from an entire geologic formation with its own ebbs and flows within it. So right there, it's massively more challenging because you've got a much wider area that it could possibly come from. That's one of the reasons why Richard Hughes distinguishes between geospatial sourcing, which is what we kind of think we're doing, and geochemical sourcing, which is what we're actually building with these things. So, for example, I could have a clay that I can identify. This is what the Mike and Ian's were using, but it could spread out across 2,000 square miles in Greece and have five outcrops that are disparate from each other, but still chemically unique. This would tell me the geochemistry. It wouldn't tell me the specific spot location. You need to be able to figure out based on the distribution of sites, which one was more likely. But with that said, yes, you can do that. In fact, there's a whole industry design by solving that question into the oil and gas industry, because the oil and gas industry uses clays to identify what layers they're in and what's the possibility of getting petroleum from that. The same thing they're doing is the same thing you would be doing. So actually, when it comes to ceramic sourcing, what I encourage everyone to be is to be a geologic paleo-climatologist. Each clay forms the specific set of oxidization conditions, local climatic conditions that create an imprint. If you have, for example, an anoxic vatic, you'll see more molybdenum. If you have a tropical location for where this part of the work was, so once I'm in a million years ago, you'll have more strontium in the soil. Because the warmer the water, the more that plankton take out the strontium, because the kinetic cost is not so large. Those little details actually help identify that. So what I can do is I can go over a little bit of deep geochemistry in soils. Now, this is typically relevant to people studying geologic processes, but you can sometimes get it short. So for example, I've got this whole geochemistry lecture, but we do it for the Great Salt Lake Basin, which was with like Bonneville and then the Ice Age. You have this like step-on-the-gas acceleration where you go through all these geochemical phases that normally take millions of years that happen in an archeological context with artifacts. So sometimes it's relevant, but that's the key, is understanding geochemistry. Because then what that helps you do is you can be predictive. If I'm studying a ceramic, and this is, one way I've been able to do it, and I see the political, that tells me, oh, this was an ad-oxic basin. And then I can pull up a geologic map and go, what formations here are A, green, and B would be at a time that there was ad-oxia. And then I can use that to localize things a little bit more. But it's not going to be nearly as straightforward as the city is because, yeah. But so the answer is a qualified maybe, I guess is the way to put it. The good news is that we have trade from say Greece to Egypt. That's a little bit more circumscribed. One route that you might want to think about working with, I mean at least following the research they do, is Ed Young. Ed Young is based at Brigham Young University, but we've been working on sourcing cuneiform tablets with him. One of the cool things we've discovered is that, so ceramics are difficult because ceramics can come from anywhere, right? And that's true of usage of ceramics, like a lot of times we're grabbing all kinds of local clays. But if I'm going to write a cuneiform tablet, I've got very specific needs for plasticity, firing, all that. And that limits the ceramic pool to something approaching what obsidian sourcing has, and that we found when we were having a lot of luck. A lot of surprises too, like a lot of times the letter will say, so and so from Babylon sets, but it's actually not from Babylon, it's a local company. And that messes us up like crazy, but there's lots of little details like that. Anyway, but I'll go into that in a little more depth. We'll definitely take you through the different geochemistries we can use to identify that, because the most important thing in ceramic sourcing I think is understanding, okay, what natural process is created. It's because that way you can rule out a lot of possible sources. And that's actually the other key thing. In obsidian sourcing, we talk about positive source associated, right? Like this is constantly on the low. You rarely are good enough to be able to do positive testing. Usually it's negative testing in seconds, right? Rejecting possible hypotheses. So I would take the framework for ceramics rather than saying, where does this come from? Where does this not come from? What can be able to do? For a lot of the material, it's just like, can I prove that this does not come from these areas that come from Egypt? Exactly, exactly. And that's the key thing. I always got a little frustrated sometimes when people say, you can do ceramic sourcing just as easy and silly as sourcing you can. But if you take the negative testing framework, it's actually, your job is a lot easier. You just need to rule out all the parts of the world this doesn't come from. And that's a much easier job than taking where it does. So anyway, all that said, what I will do now is we're going to go backwards a little bit, and we're going to cover basic XRF 101 for those of you who are new. And then we'll kind of fill into some of these more advanced topics. Are you a chemist in the background or a physicist here? Archaeologist. Lake Bronze Age collapsed with my jam. A little bit of stuff in the chemical canyon. Did you just pick up all this on the side? Yeah. It turns out when you put someone in front of an audience all around the world every day to talk about this, you get a physics. But yeah, my name is archaeology. I'm going to totally brag here. I had to do this workshop in Fusco. And I had to do it in Spanish. And it was so hard. My brain felt like it was melting. But at the end, a PhD physicist came up to me and asked me in Spanish, what was your physics PhD? And I was like, yes. This is like my atta. I'm never going to do that. But yeah, in any case. But yeah, if you have any questions, let me know. I will be very generous with what I don't know, which is a great deal. But I can point you to someone who can help as well. One of the best benefits of working with Brooker and having to do these workshops is I've been able to become like this networker in chief where I can put random scientists who never knew that they had similar problems in touch with each other. So I'm happy to do that. I'm going to be doing this with Lucas and Soybe, a specialist in Ethiopia. There's a lot of a family of leaf work. So yeah, in any case, I'm going to hit specifically because Ethiopia is the hardest place to do extra work in the world. So for two reasons. There's the legal reasons because Ethiopia was very strict. And then there is the bizarre African curse, which plates instruments and causes them to fail for some reason that we don't know. Because when we look at Brooker, most of the instrument failures that are like abnormal have happened in South Africa. So. And there's elevation. It's the elevation, but like a lot of the units failed at minor elevations, even in places like Kenya where you're close to sea level and we never figured out. We know that the new units don't have this problem, but the old unit, something was going on with the way that we needed it. That blue unit is still working as a background actor, right? The blue unit is? Oh man, that's amazing. I think Steve brought it back to me. He smuggled it back into detail. The one question I would actually like to ask is if this college professor, if you're borrowing your unit to do something. Yeah, put it in the question. Steve. Perfect. I'll do that. I'll do that. Yeah, because like one of the things I'd like to do is there's so many archaeologists figured out how to get a unit, this crazy part of the world. And usually that part of the world also has a lot of subsistence farmers. So if we can actually say, you know, for when it's not field season, when we use this unit to help the poorest of the poor farmers, not spend 90% of the disposable income on a phosphorus fertilizer, they're not going to use and put that to the education of their children. There's a lot of good archaeologists can do in that department, just by letting borrow, loaning the unit. And the good news is it's all 15 KED stuff, so like the risk of hard to eat it is so low because it's all like other things. So anyway, well, let's start with, I'm so sorry, Nico, Lucas, you've heard me go through this thousands of times, right? Hopefully it's entertaining. But what I'm going to do is talk about x-ray fluorescence. We're going to talk about regular fluorescence, in other words, how we see colors. So the best way to learn what's going on is to go very bare bones. What are the specifics? And before I do that, I'm going to email our friend and tell him we're videotaping this. And we'll send it to him somehow, because he's probably very worried. Nico, if you're CC'd on that, if you could just email him, I can't see it. With a new Gmail app, he's actually archiving everything. So if I do respond, he has clumsy thumbs. Anyway, so, color fluorescence. What we have here is the spectrum of light on a tropical ocean. So this is basically the radiance we have. So over here we have, and this is color, so that's red, that's green, that's green, blue, violet. What do we call that stuff? Over here, that's lower in way of light than above. Ultraviolet. If it's lower in way of light, it's ultraviolet. If it's higher in way of light, it's infrared. If that's confusing, I totally understand, it makes a lot more sense when we use the parenteria of light, but wavelengths are weird. But in any case, if you look at this graph, I want to ask you a question. Why is the sky blue? Because it doesn't absorb the blue. This is true. This is true. But it also doesn't absorb the green, the red, and the yellow, because we still see those down here. Why is the sky blue? Well, let me make it even easier. What's the tallest point on this graph? So why is the sky blue? There's more up here. So like one of the things I remember, do you guys ever read XKCD? They've got this great comment where a teacher, where he goes, a smart teacher, and it's a kid asking, why is the sky blue? The teacher says, well, it's really a scattering of light. And then a smart student follows the question, why isn't the sky violet? This is why. Because violet's less than blue. There's just less other. So for example, the equivalent here would be, if I take, you guys know what I'm sitting in, if I measure a piece of the city, what's the tallest part of the spectrum, right? It doesn't mean that there's like so much iron. It just means that type of light that I just sent in the artifact. It's iron preferentially. Iron would be the equivalent of the sky being blue. And there's just more of it. That is all. Next question. And this one's super tough. Why are plants green? Right? They're all green. Why would they be green? That's the light that they don't look like. So why aren't they black? Right? Why aren't they black? If they were black, they'd just be green all the way. Why would they preferentially go for one type of light in particular? Well, look at this graph. What is, because it's over here, nothing on either side of that. Yeah. We'll come back to this in a second. I want you to halt this question in your mind. Because understanding the relationship between why the sky is blue and why plants are green are the key to optimizing your x-ref unit in general. So now real quick, one third question, and we're going to answer all these in detail. Why is this not smooth? Why do I have these divots and rumbles in the spectrum? Why is it up here? God is the end curve. What's going on? Well, what's, is this traveling in a vacuum? No, there's stuff. What's stuff is that is in the light's way when it comes to Earth. Particles. Particles of what? With like this? Grass. Grass is, but like this is just the light coming to the Earth, right? Nothing, like, so if I'm like on the ocean, on a boat, and the light is coming down to me, this would be that stuff, right? What is between me and the source of light, which is the sun? In the atmosphere. Yeah, what's in the atmosphere? Gas is oxygen. Gas is oxygen. Nitrogen, there's that 0.98% argon. So that's why it's absorbing? It's absorbing. If I was in a spaceship and I was looking at Earth, I'd see the opposite. I would see these as peaks because I would see some reflection of that. There's actually a few guys that know Carl Sagan's blue dot, where he turns the satellite back to Earth and gives us a little speck of blue dot. There's another thing they did with that same experiment. They used the reflection in that blue light and said, can you prove there's life on Earth from a satellite? And they could actually see the water in our atmosphere because the water reflects a certain wavelength of light. This is why when you're watching like a TV special and you hear scientists about a new planet and you think it might have water and you're like, how do you know that? That's ridiculous. Well, the light that comes from that planet will reflect its composition. You can train a telescope on the Jupiter that gives the difference in the infrared spectrum. You see that guy right there? And you can tell what it's atmosphere is made of. All that is encoded in the light that comes back. This is how we know all stars are made opposed to hydrogen because when you look at their spectrum, hydrogen is like this shiny peak that goes always there. So yeah, there's a student who's at John Hopkins University. She's working in Northern Ethiopia where we've worked before and they're using satellite imagery to detect their city and sources on the ground. Really? So they're not, they don't know what that city and source is, right? They're not going to give you a picture. But they can see the absorption of the, yeah, exactly. There's a ton of information encoded in them. This is actually where drones I think can be the most crazy because if you put a certain infrared camera on a drone, the analytics you can do on all the wavelength scatterings that are happening with the visible light, there's a ton of information here, an absolute ton. And really the trick is, is just zooming in on one or the other. So yeah, I know one proposal I heard that was super interesting is they want to use infrared here to see nitrogen in plants just by cruising a cell over a field, a drone over a field. So yeah, there's a ton of information there. And actually an archaeologist who actually kind of went out of her, we use light arm pull-up camera. And this is essentially what light arm is doing. With light arm, they send in this stuff that doesn't get bothered by this stuff. We don't have the rainbow plants anymore to distract us. We see right through them with the infrared, we can see the topology of the graph. So archae, by the way, this is actually the other parallel that we found that I found working at Brooker because I was like, why would a NASDAQ company want to hire archaeologists? Well archaeologists are going to get down on ourself because we just borrow all these sciences from other groups. But actually we're farther ahead analytically. The epistemological questions you guys asked, we're going to make city and city, is 20 years ahead of, say, a lot. So for example, I told the joke earlier today, so you see this exorethia, right? This is a prototype of the tracer fly by that was made a few years ago at Brooker, but you'll notice it doesn't look like anything. Brooker product is supposed to be white and blue, that's it. This one does not that. Like actually this is a problem for Brooker. If corporates saw this, they'd be in so much trouble because it doesn't have the purple and blue color on it. Well the reason for this unit is when I went to my first agronomy conference and I asked people, I told people I'm working with extra fluorescence, because to me it made obvious sense, like exoreth can do a lot of stuff with nutrients. Like just stopping phosphorus from running would do so much good for two reasons. We would stop polluting the oceans and second all these farmers would stop buying all this phosphorus that they don't need, right? If it's going into the oceans, it's not being used by the plants. And you would know that by just checking there. Exactly. If I have a corn plant and I measure its leaf and I say, you know what, this phosphorus is typical of what a normal mace plant needs. I'm good. Or I can measure the soil in like one mile increments across a vast area and I can map where's the phosphorus level. You can precision target where the phosphorus needs to go. They just take a lot of money. Oh, there's so much waste in our agricultural system inside your body. So anyway, so I was like beating the drums at Brooker. I'm like, you have to do agriculture. I'm super proud because they had someone dedicated to agriculture and now agriculture has risen to actually, if growth rates continue, agriculture will outsell archaeology and art and at Brooker for these units. So just catching up. But if you look at this unit, you look at it and it's green and blood, right? So at this agricultural conference, I was at, I said, I'm working with x-ray fluorescence and they would tell me, what does that do? And I said, well, we, you know, see elements like iron and the sun that hide and that could help us learn things. And they said, oh, we don't need elements, we need nutrients. And I said, well, what nutrients do you need? And they're like, you know, phosphorus, calcium, potassium. And I was like, so I told her, John Deere, make it in John Deere colliders. And that, that changed everything. But like, let's, but like, when I went to this group in Africa, I called ICRA, that their headquarters in Nairobi and we're doing this, and they would just do what we were able to do with this plant. Because if you think about one PPM strontium in obsidian, that's tough. Half a hundred percent phosphorus and plant, that's easy. But that is what the world needs right now. And so they were just astonished at what we were able to do, non-destructively and rapidly, right? Like if I do wetland techniques to figure out nitrogen in a plant, I have to wait a week to get results. And there's a lot of man-hours for acid digestion. Here I could do it in 10 seconds. So they were just, their minds were blown. And they said, is this technology new? And I'm like, no, it's been around for 20 years. And they're like, well, what do you think you're using for this whole time? And I'm like, you know, find out where rocks come from stuff like that. So archaeology is ahead of the game in a surprising number of fields that includes XRF. I suspect it also includes light on it. Like we shouldn't be done with results. We're on the cutting edge a lot more often. And it's because it makes archaeology special. We can't destroy the object, right? But we can't just grind every piece of obsidian to a powder and send it off for nutrient, or you know whatever. You can't do that. So we've had to be adaptive. Because we've been adaptive, we are light years ahead of most other fields. And I found that a lot of my work at Brooker, which is translating advances made in archaeology to other fields. An example of this is this group in Africa was going to has, I think they've got 25 of these units now in networking countries like Ghana and Martinia working under gene analysis. The original idea was let's use fundamental parameters. Well, we in archaeology were married to that while fundamental parameters were great for companies, it's not a great way to compare instruments from one to the other. And the core need of this group was to be able to directly compare fertilizers. So if you've got a company that's selling bad fertilizers, you can use evidence for two different distribution points to say, these guys need to be out of the business. We're going to do legal proceedings and yadda yadda yadda. You can't do that with fundamental parameters because the units are not comparable to Speaker Shackley 2015. So it's key, absolutely key. We've done a lot of the hard work for the rest of the world in archaeology. So anyway, pat yourselves in the back. But like all these spectral manipulations, things we talked about, whether it is LiDAR or XRF, archaeology is actually out of the curve a quite a bit. Astronomy has been there for like 50 years, but they're so hard to talk to. It leaves advances to not trickle down. Now, one thing you'll notice here is this x-axis is in wavelengths. And like as you noted earlier, the nomenclature doesn't make sense. It makes a lot more sense when we use energy instead. So in this case, the x-axis is in energy. So red is 1.7 volts of energy. Blue is 3 volts of energy. Infrared is below red. Ultraviolet above violet. See part of the theory way better than wavelength. But in any case, that is a safety. Now let's come back to our but now we'll put a question. Remember you say why is this guy blue? More. More. Now let's answer. Why aren't plants green? Well, so real quick, an XRF. Is it reflectance or is it something else? When something fluoresces, is it just a passive reflection of a photon coming in or something more complicated? I've got a photon that comes in, the electron jumble around and a photon comes out, right? So which has more energy? The photon that goes in or the photon that comes out? So more energy has to go in. Which is the most common color that we have in the sky? Blue. So if plants are absorbing that blue, what color would they be? They'd be lower energy, right? Green. So the high energy blue is absorbed by the plant. It splits carbon from oxygen with that light and then it fluoresces the residual the light did not need, which is green. If I chop out the blue, green is left. That's why plants are green and not blue. So like a lot of little details here, but that's basically, hopefully this is making a little more sense. You start to, by the way, this is the core of what we call the anthropic principle in physics. So the anthropic principle is why are the laws of the universe here? Well, because if they weren't here, we wouldn't be here. Like their existence as the precise way they are is the reason why we can observe them. That's kind of the blue-green plant phenomenon, right? Like the reason we're here at all is because plants figured out this trend. If plants hadn't figured out how to turn blue and green, no animals would have ever evolved because there would be life on earth would be very different. Yeah. So if for other parts of the plants, like the part where the plant, if it's a flower that's blue, it's because it's taking in the ultraviolet light and exactly right. Exactly right. Perfect. Let's add that a little further. So let's say Lucas really wants to screen it. And so when no one's looking, he splits my throat, hikes the body, cleans up everything. It's very thorough. The police come in and they want to see if a murder happened. What type of light bulb do they bring in to test for that? Ultraviolet, right? What color, where's ultraviolet on the spectrum? Right over here, right? So then they turn on the lights and they put the ultraviolet with the blood. What color is the blood? It's kind of a bluish, right? So the ultraviolet goes in, higher energies and kicks out a lower energy, right? That's the essence of fluorescence. More energy goes in, less energy comes out. If you apply this to your spectrum, this is why it's almost like the city, like this entire technology was made for the city because rhodium is just at a higher energy than rubidium, strontium, and term zirconium. So the material we make is perfectly optimized for strontium and zirconium and all that. It's super cool. It blows my mind the more I think about how perfect obsidian analysis is for this technology. But in any case, that is the crux of it right there. More energy goes in, less energy comes out. That's what makes fluorescence so important. By the way, one of my favorite little scientific anecdotes is when the scientists who discovered the relationship between energy and light was doing a funny experiment. So he wanted to measure the temperature of light. So he took Newton's prism and he put the prism there and then the light shined out. This is like in the 16th century. It's a very early on, but he liked Newton's prism, shined the light out, and so he had this table and you can see the violet, the blue, the green. And then he put a thermometer on each one. And then to the right of red, he put his control thermometer. And so he could measure the blue, the temperature of blue, green, nothing much is going on. Red, a little hotter. And then the control was like five degrees hotter than everything else. And that's what infrared light was discovering because this control should be a completely different phenomenon. But in any case, that is the crux of it, right? By the way, my favorite example of everything we just discussed is the month cell color chart. You guys have used this in the building so much, right? So at the University of Mexico, right at my degree, I remember I was working out a chart bill and we had a student go in, go out, and they used the month cell solar soil chart out in bright light and they say, okay, 5.0 or brown, you got it, you got it. They put it in the lab, they sent it to the lab, and then the new student opens up and goes, Mr. Brink, this doesn't make any sense. Their color is not the same color that's down here. Pull on that button. Have you had that phenomenon in a month cell color chart where you look at someone's written script and you go, I do this. Hold on to that because this is going to be the source of all that. The key thing here is that the light source itself changes everything remarkably. Now for those of you who haven't used x-ray fluorescence, this is our color fluorescence world, all these same rules apply to the x-ray world. The only difference is instead of 1.7 to 3 electron volts of energy, we use 1,000 to 40,000 electron volts of energy. So we use a much wider spectrum, and that much wider spectrum gives us different colors. So if red, the color of this iPad there is 1.7 electron volts of energy, aluminum is 1,440 electron volts of energy. Now if I just have a block of aluminum in front of me, it's gray, right? Because I'm not taking in the right color to show the color of aluminum. That takes x-rays. So when we say x-ray fluorescence, we're using color object, we're just using the color of the elements individually. When you see the piece in the spectrum through a video in strontium, that's the color of strontium in a video. The intensity of the color corresponds to how much of it is there, but it's all colors at the end. If I take this unit and I map a painting, I just create a painting of the new sleet of colors. I'm using more of the light that is available to me, and that's all. So that's the best way to approach x-ray. And that's how we do qualitative work with it, technically speaking. And I suspect a lot of your sourcing questions can be addressed, but if your very core question is, is this a local Egyptian ceramic or is this a Mycenaean ceramic? Or is it, you know, yada, yada, yada, you can identify the elements and the pigments qualitatively. A high iron peak on the black will tell you it's Mycenaean. You don't need a calibration to tell you that because you know the methods behind it. I also think for those of you who have built calibrations, the most important step in quantitative x-ray analysis is qualitative analysis, right? So Lucas, give me a great example. Can you explain the person who is having the problems with the speckling shift? They, well, they were, they had a tracer group three, and they scanned a collection of source samples one year, and then over the course of their using the instrument, they found that they couldn't match the artifacts that scanned after the sources, and so they rescanned the sources and then they were able to match. And in that case, it appears that they were not paying attention to where, to what was, where the actual measurements were lying on the bottom on that x. Exactly. The speckling shift, they weren't paying attention to the quality, the qualitative data. They weren't paying attention to the parts per million that were being spit out afterwards. Exactly right, exactly right. And that's where you get the biggest problems. The failure to do qualitative analysis undermines quantitative. I like to think of quantitative as the top of the pyramid, qualitative as the bottom. And if you don't have a foundation, you're not going to have a great peak. So yeah, absolutely true. Anyway, so that is that process. Now let's dig in a little deeper in the color fluorescence so that we understand it as well as we possibly can. The first step in color fluorescence is that a photon comes from the source. Where's the source of photons in this room right now? Where they come in front? Up here, right? And then if I were to, I'm gonna come back behind you guys over here, if I were to open up this curtain source now. Not quite as bright, but yeah, we have a different contribution. Are these identical sources? No. What is the most common light coming from this guy blue? Look at it, what color is it? Yellow. So this is a different scatter, right? The peak of this light will be yellow instead of blue. Do I get ultraviolet from these lights? Do I get infrared? A lot of infrared from these. No. Do you remember the old light bulbs? We got a lot of infrared from those, right? The incandescent. Because they were just using resistivity of tungsten to electrons. And so most of that curve would have been on the infrared side of this spectrum. 90 percent of them were heat. So to show you an example of this, this is a laboratory, a conservation laboratory from Washington DC. They've got two bad conservators who don't like each other very much. They don't cooperate. They're very much in their old middle worlds. The conservator to the left uses full spectrum LED, so that way the light in her basement is the same as the light from the outside sun. The person to the right uses, is on a budget, some regular fluorescent lights just like we have right here. Can you see the line that falls right there? Now look here, you see that blue pyramid? I can see the color blue right here, but then I look at the recycling bin. I know that's blue too, but it's black because the yellow light is not sending out enough photons to excite blue. Right? Because if we go backwards, yellow is lower in energy. Can yellow excite blue? Can't. By the way, this is why plants don't do well inside. Like we can't just turn on the light bulb. If I had a full spectrum LED, it's a different story because then they've got the blue light that they need. So if you ever need to grow a plant in the winter, use blue, make sure you have a blue light source. But yeah, so that's the distinction there. Let's come back to the one-cell color chart. So I had a student say, hey, this is five white-art brown outside in the bright sun, and then they go to the dengue fluorescent lit archaeology laboratory that has these yellow skewed lights, and all of a sudden that color is different. Did the soil change properties? No, what changed? Just the light source. That's all. This is why whenever you do the one-cell color chart, the field wins. Because the sun is the same in New Mexico as it is in California, as it is in Egypt. But each lab, each these fluorescent bulb can be a little different because of different colors. I can't tell you how much good data was deleted in my time because I saw a student. I didn't understand the physics of it. I assume you know the student out in the field. They're hot. It's difficult. I understand why they wouldn't get the color. But no, you need to do the sun. There's two reasons to do the sun as your primary source for describing artifacts, or even our eco-facts. Number one is use the sun as the common light source because if the sun, the sun never changes, right? If the sun changes, the least of our warriors is going to be these differences from China and all that. And that gives us a standardization for everything. And number two, the variation in these consumer-grade light bulbs is so large. Even these two, if I were to create a spectrum of light from them, I will have little differences. This one might be more red, this one might be more green. Those little changes you have. So if you ever take a photo of an artifact, always, always, always use open sunlight, or make the investment in museum quality full-spectrum LEDs, it sounds a little bit crucial. Where they discovered this problem in museums is with art collections because in the 1930s, you would have someone take a da Vinci painting and they would bring it down to the conservation lab and they would start touching up the painting under these lights. And then they'd bring it back up into full sunlight in the museum and go, whoa, what happened here? So yeah, it's crucial to use the same color source. So that's the key thing. The source of what predicts most of its color properties. Yeah. So a year ago, when I first started using the tracer and I was telling people about it, someone asked me, can you use it inside or outside? And I said, well, why is that important? They said, well, doesn't the sunlight affect the x-ray that come out of that? No. When I said, I've never heard that, but I never really understood why they might ask that because the sun is somehow more powerful and you can interrupt the x-rays, the light that's coming out of that. So that question right there gets to the heart of what makes the particle theory of light different than the wavelength theory of light. So have you guys taken physics? Do you guys have? Do you have to do de Broglie's equations where you have positive and negative interference of wavelengths? So the idea is, like, you buy the ocean, right? And if the flight is a wavelength, you buy the ocean and you've got waves coming in. But they're at slightly different speeds. Sometimes the wave will come in and it will interfere with the existing wave, very different things. And so the wave that breaks on shore is very weak. Sometimes they build up on each other just right. So you get this surge of see-