 Well, thank you very much, Leonhardt, for the introduction and welcome, everybody. I'm actually speaking to you from Kelerin, north of Glasgow, so I'm in Scotland at the moment, not in Amsterdam, not where I work. And it's a delight to be here and I'm incredibly grateful to the Royal Philosophical Society of Glasgow for the invitation to speak and to present the Minerva lecture. Minerva, of course, was associated with wisdom and the patron of institutions of learning and the art of the arts, crafts, music, magic and sciences. So in fact, she represents this almost, you would say, an interdisciplinary approach, which is, and I left the war out for now because she of course is also the goddess of war, but let's stay with the association with wisdom. And she represents almost an interdisciplinary approach that is exactly what technical art history is. So I focus my research on how art was made and all the facets that connect to that, everything around that, the cultural and artistic environments artists and artisans worked in and so on. And to be able to do that, to really try and get into the skills of these artists, it's really important to work in an interdisciplinary manner. And I do work a lot with scientists because we now have many, many scientific methods available that will help us to analyze artworks and objects to understand how they were made. Coming from the Rijksmuseum, I can't of course start this talk without telling you a little bit about Operation Night Watch, which is the biggest conservation project so far that the Rijksmuseum has engaged with. And here you see the glass house, as we call it, built around the Night Watch. And there's a stage in front of the Night Watch where all kinds of equipment is being used by all kinds of scientists, a whole big team of more than 30 people are working in this project, many of them young postdocs and PhDs, all with different expertises, working with the curators, art historians and technical art historians to really understand what Rembrandt was using, the kind of materials, the kind of techniques, why certain materials age and degrade to really map that all. And so this whole last year, despite the lockdown, fortunately quite a lot of things could continue. And I was just told that they collected 600 tetrabytes of data from all the scanning and all the methods, that imaging methods that have been used, which is massive if you know that the data on all the whole collection of the Rijksmuseum, which is a million objects, is around 150 tetrabytes. So that is the modern way of examining artworks, lots of data, but then all these data need to be interpreted. And I'll just show you an image of the Night Watch and detail of the beautiful embroidery that you can see there in the center. And we now can zoom in and get so close to the paint surface that we really can see every brushstroke and every pigment particle almost present in the paint layers of Rembrandt, here's another detail. And these photographs are taken in super high resolution, but they will tell you so much that it is really important for the conservation treatment as well to make decisions on how to clean the painting, do we clean the painting, what kind of treatments are we going to do, decisions that need to be made, but also to get really close to understanding what Rembrandt was doing here. Well, that brings us to the 16th and 17th century period of painting, which will be my major focus during this talk. And I want to start with a quote, and I won't quote a lot, but I will start with this quote from Philip Angle. He was a painter in Leiden, and he gave a speech to all Leiden painters who were specialized in very detailed painting. He called it in place of painting and it was done in 1642. He states that we say that the art of painting is far more general because it is capable of imitating nature much more copiously, for in addition to depicting every kind of creature like birds, fishes, worms, flies, spiders and caterpillars, it can render every kind of metal and can distinguish between them, such as gold, silver, bronze, copper, pewter, lead, all the rest. It can be used to depict a rainbow, rain, thunder, lightning, clouds, vapor, light, reflections and more of such things. Like the rising of the sun, early morning the decline of the sun, evening the moon illuminating the night with her attendant companions, the stars, reflections in the water, human hair, bosses foaming at the mouth and so forth, none of which the sculptors can imitate. This was of course about the so-called Paragona, this comparison between what sculptors could do and painters could do, so there's a little bit of that politics in here as well, but he was talking about painting as an art of illusion where you could create in paint any material and any part of nature. And on the right you see a very small painting by Gerard Dau, who was one of the fine painters in Leiden and this is all about that deception. You see the niche which is made of stone, you see the book sticking out almost in our space, you see the curtain which is, the weave has been identified as a certain type of silk because it is so detailed. And of course the whole thing is a trompoli with this curtain that is seemingly outside the painting, but it is actually painted part of the painting. So how did these painters build up that kind of skill? How did they get to really be so technically able to deceive, if you like, and to create these solutions? That was a long road and I'm showing you a model here that comes from the book of Roger Kneebone, which is called Experts, Understanding the Path to Mastery, and I can really recommend that because it's a very wonderful description of that, but the model that he uses is a well-known medieval guilds model because in the guilds you would be trained and there were regulations on how the training would be, but you would start with doing time, learning in the studio, you would use your senses because the whole making of art in that period was very sensory, you needed to understand how something would feel and how something would smell when you were preparing something, your sense and your eyes, everything was part of that. And it was, you know, you're part of a space with other people, so in a workshop you would collaborate with your master and other assistants and apprentices, the whole sort of choreography between all these people in the studio. Then you would become a journeyman because you're now experienced and then you start to develop your own voice. It's no longer just about you because you can start teaching others as well. When you become a master, then it's all about passing on that knowledge and that experience and that skill. So how as a technical art historian do I learn about all these things? Well, first of all of course by examining artworks but also very importantly by looking at all kinds of texts. And those texts are treatises and manuals, recipe books from the medieval times onwards up till even now. And those are repositories of artisanal and artistic knowledge as I call them because there you find jotted down, written down, all these kind of instructions and recipes. Mind you, many, many times they are not that clear and there's a lot of knowledge in there that is not written down. Like we would not write down every step in making a cake or baking a bread because we know it so well. You leave those kinds of things out, a sort of tacit knowledge as we call it. But still there's a huge amount of information. I just show you some examples of these wonderful texts on the left, a German text all about working in copper on making engravings on the right, an Italian book of secrets with lots of different recipes for color making, but also more modern ones like paints and color mixes. And you see the little samples of color or a book on dyeing textiles with little pieces of cloth in the different colors in there. And there's many, many more. So to explain to you how this all works, I would like to tell you a couple of case, present to you a couple of case studies. And the first one is a case study of mastering color. And I will start again with one of these texts. And it's a really interesting, very unique text by a certain A. van der Bogert, a Dutch man who wrote this, the clear light, lighted mirror of painting. And on the left you see the title page with a beautiful butterfly. It's dated 1692. And he wrote it in Delft, the city of Johannes Vermeer. On the right you see the title page, the clear light in the mirror, their fervor with the painter sitting here drawing, painting in a beautiful frame and his assistant's grinding paint. This is 800 pages. And it is in Exam Provence in the Major Library. It's a very unique document because it's very small, about this high. And every page explains a color or a mixtures of color. For example, here you see on the left is always the text. And on the right you have the samples of color. And this is another couple of pages from it. And you end the book with a register which has all these different colors. And it says on which page you can find instructions on how to make that mixture. Well, this is 800 pages long and it represents the main pigments. And it is totally unique because it's like a Pantone color chart, but then from the late 17th century. And we've never found another book like this. So why would somebody make a book like this? Well, very recently we found something really interesting. And that is another three volumes of books which have images, watercolors of all kinds of animals and insects. And the title says various types of lizards and dragons, seahorses, crocodiles, snakes, etc., etc., all kinds of animals, including very big ones and very small ones like winged animals, which is insects. And it's made by Adrian van den Boogert and the handwriting we found very similar to the color chart book, if I can refer to it like that. And in the title here of this volume, and you see one page of butterflies from the volume, it says that all this is painted after its own natural colors observed and drawn after life. So after nature, the way it looks in nature. In the color chart book in the introduction, the same Boogert, we think, right, come and read this book, which will engage you as both through the eye and through text. You will be taught what to do to give everything after life, so after nature, its color and character and character properly and accurately. And that is why this book is full of colors and how these are prepared, you will see presented next to them. So that is really interesting because we think that there is a clear connection here between wanting to depict all these animals, butterflies and insects really accurately after nature and needing to have the right colors. And if you would have a color chart like that, all you needed to do is find the correct color if you have a preserved butterfly there. And then the book will tell you which colors to mix, which pigments to mix. So that was really fascinating. And then placing that into a bigger context from exactly the same year, we have another text, which is called the big world painted small or colorful tableau of the world's painting concisely. And this is a treatise by a painter called Will Helmuss Burrs, written and printed in Amsterdam 1692, the same year as the color chart book. And again, you see here the title page and the image with several young women painting and it's dedicated to his pupils, female pupils. Burrs talks a lot about the mixing of different colors and says that with regard to the mixing of colors, then this art appears infinite, an indefinable sea in which a person can lose his way. For this reason, a painter can best apply himself to mastering that which is most in keeping with his individual character in order to experience the greatest pleasure in aspiring to a high degree of perfection. So clearly mixing colors, understanding all these things is a really important skill of a painter. And this all connects really well because Burrs also talks about the way you then use these colors. And I'm showing you here two paintings by a painter called Otto Marzijs von Schrik, an Amsterdam painter and Melchio de Honderkoeter, contemporary of von Schrik. And these pieces are so-called Soto Bosco scenes, which means forest floor. They're all in the forest, you know, when you go into a forest and suddenly there's so many trees and shrubs and it's dark and damp and you smell the mosses and the lichen and you can imagine all these moths and butterflies and mushrooms and snakes and lizards all in there. It's all symbolic for the tangents of life, life and death, that kind of iconography behind these paintings. Well, Willem Burrs, the treatise writer that I just showed you, dedicates a whole chapter to this. He starts with creeping things and other creatures of that nature. He mentions snails, worms, snakes, adders, lizards, scorpions, toads, frogs, which populate these so-called Soto Bosco scenes. You can totally see these dusky woodland settings composed of all these mosses and toads, tools and dead tree trunks and they are found in these works and several other painters who also, Dutch painters who also start painting these scenes. Burrs gives detailed instructions on how to paint one of these creeping things, namely the water snake, but refrains from describing any others because a painter who has the life situation before him says Burrs will be able to paint it well enough. So you needed to have the real thing, the snake, whether it is a stuffed one or a real one or one in a jar, but clearly that is what he aims at. To create this life situation, some artists indeed collected a variety of these species themselves. So the painter and writer Arnold Haubraken explains in his great theatre of Dutch painters how Marzijs van Schrik, the painter on the left, raised snakes for his own use and how the snakes after some time were so used to him, says Haubraken, that he, when painting to, when wanting to paint them, puts them, pushes them with his mouth stick in the position he needed and they would stay still until he finished painting them. Sounds a bit unlikely to be honest, but that is what Haubraken writes. Another painter and theorist Van Hoogstrammel van Hoogstraten describes how he visited Marzijs van Schrik in Rome. He traveled to Rome like most painters did at the time. He visited him in 1652 and marveled at the many monsters the painter owned, and I quote, whose nature he understood so well that he could depict them very lively indeed, end of quote. He was nicknamed in Rome by the local Dutch and Flemish artist community, the snuffler, the sniffer or forager for his collecting of all kinds of reptiles, insects and strange plants and herbs, an activity he continued when he returned to Amsterdam in the 1660s. So Van Schrik as well as Rachel Ruys, and I'll show you a work by her later on, who was the daughter of the famous anatomist Friederik Ruys, sometimes applied real butterflies in their paintings, and we touched them just a tiny bit with oil paint, just forging a close connection between nature and art and striving, you could say, for the ultimate realism. And we know that many of these paintings, well, we hoped to find a lot of these butterfly wings in the paintings, but that is the research that is still ongoing. This getting really close to nature and this ultimate realism is not new in that sense. So here I show you a beautiful watercolor by yours Hofnagel from almost a century earlier of these insects here and the wings that you see in this image are real wings. So this whole way of working was not new in itself. And we know that Beurs in his treatise describes several scholars that provide examples to painters of all these animals and insects. And one of them, for example, was Johannes Gutthard. And here you see the title page of the book from Gutthard. So the theater of caterpillars, worms, maggots and small flying animals coming from them collected from my own experience. So again, also from the science side, this real direct experience is very important. He illustrates the three volumes with woodcuts, which were not taken from other books but described and drawn based on the author's observations. And even now and then describes the colors that you would need to color them in. So very nice sort of crossover between the science and the arts here. And he describes how he used a magnifying glass to be very accurate. Going back to von Schrieck and the real butterfly wings. This is a piece of research from colleagues in France who looked at this particular painting from von Schrieck and the butterfly that you see. And that is a detail we are going to look at. They are researchers from CRMF2 in Paris. And the painting is in Grenoble. They believe von Schrieck actually prepared the wings with a method that encapsulates them in a varnish. A method known as Lepidochromy which is described for the first time in 1780 in France. So quite a lot later. So that is still a big question. But looking at what they found, you see here at the top the preserved wings from a butterfly front and back. And the real wing here without the varnish. And here the wing is covered with a varnish. You immediately see an issue here because there's a change of color, the blue, an addition blue in these wings. Then with a varnish covered has a similar refractive index. You no longer see it. So that is also interesting because this is that butterfly that we see in the painting. This detail you see here. And these are the scales of the wings of the butterfly and they're stuck into now seemingly a white paint that was all underneath the whole butterfly. And this blue actually is paint. So von Schrieck retouched where the blue was no longer visible with a little bit of Lapis lazuli blue, ultramarine blue. Very, very interesting. This of course is still part of research. And in 2022 the Rijksmuseum organized a big exhibition with, amongst others, paintings by von Schrieck, the Honderkutter and Rachel Ruis, where we want to do extensive research on these methods. But you can understand that von Schrieck must have looked at how butterflies were preserved at the time, the different methods, how to do that. And that is something the French researchers called Lepidochome, but is that what he did? And there's a lot of work there to be done. But he clearly adopted yet another skill next to being a perfectly capable painter. He could, of course, paint these butterflies in paint, but he made himself obtain another skill to be able to actually really introduce these wings in the painting. Unfortunately, many of these wings, the pigments fade and many of those butterflies now look quite pale. They did do other things as well. And I show you here two paintings by von Schrieck and Honderkutter. And if you zoom in on the bottom part, then you see all the mosses and lichen there, which you would typically find on a forest floor. And there, too, the patterns are very unusual, not something you can do with a brush. And it is most likely that they used real lichen and real mosses to stamp a kind of paint on the surface. And when you look at a cross section from that area, and the cross section is a tiny, tiny sample that we can take very rarely, but we sometimes take a cross section the size of a grain of salt. And we embed it in a piece of resin and then polish it in a right angle so we can actually see the sandwich of the layers of ground preparation, paint layers and varnish layers. And that is what you see in this image here. So one is the ground layer, two is this green layer underneath that you see through. And then there's this white and then a yellow and another greenish layer. So the white is actually the stamp of the lichen and the mosses. And it's probably done with a different kind of paints to be able to do that. We've been experimenting with that and they needed to manipulate the binding media to do that. Absolutely fascinating. And it connects very well with the interest in nature printing at the time already introduced by Leonardo Da Vinci. You see a leaf of salvia with his text around it. Da Vinci is not so happy with the result, so he doesn't pursue it, but others did. And here you see an early 18th century page from a book about how to actually do it. And it shows an absolutely beautiful nature print. So this realism introducing these nature prints is really fascinating. And this is a painting by Rachel Reus. I mentioned her already, a fantastic painter who you can admire in the Calvin Grove Art Gallery. It's one of my favorite paintings. It's not the best image. It's a beautiful painting with the mosses. The lizard definitely look at the lizard. It's absolutely stunning how that is painted. Lots of questions about that. Butterflies there too. And what is so really nice that just because I like it so much is this is two pages from a Tessauro's Animalium primus from her father, who worked with artists who made prints where you see animals and other kinds of species in a jar. And then he represented that in this volume with snakes surrounded with insects and with this beautiful sort of still life arrangements on top where everything seems to come together. So the impact of the father on the daughter and the other way around is definitely present here. So this whole environment of these painters so closely connected with natural scientists comes out in these paintings. And so understanding what artists do and developments in their skill, we always need to need to look into this broader environment. Another story, an unusual story of skill building and material intelligence, if we if I want to call it, if you can call it that way, is the following. So we're talking about material intelligence. What does that mean? It means that an artist or an artisan knows the material so well that he knows exactly what he or she can and cannot do with that material, what the material allows or not. Martin Heidecker describes this very, very succinctly in this quote here, if he, the apprentice, is to become a true cabinet maker. He makes himself answer and responsible of all to the different kinds of wood and to the shape slumbering within the wood, to wood as it enters into man's dwelling with all the hidden riches of its nature. In fact, this relatedness to wood is what maintains the whole craft. This relation to the material is really, really important for skill building and understanding what you can do. A beautiful example of that is live casting. Live casting is done in many, in various ways in the 16th century. So we're going a little bit back in time, but we stay with this art-nature relation after life, after nature. So here you see a couple of examples of details of the beautiful ceramics of Bernard Palaisie, a French ceramist, where all the animals like these beautiful lizards were cast after life. That was not such an easy thing. When they were digging in Paris, not so long ago, to build in the center of Paris, they found the former workshop of Palaisie with lots of these kind of examples of molds for casting live animals that he used. So in enormous richness there of all these kind of different materials came up, which helped to reconstruct what Palaisie did. Palaisie himself also wrote about that in his treatise, this score. And he talks about the trial and error, if you like, in skill building. I'm not going to read the whole quote, but he talks about the experience is the mistress of the art. You have to do it again and again and he says, some of my animals turned out fine and well melted, others were poorly melted, others were burned, showing how difficult this all was. And he finishes with, I was like a desperate man, I had to do double work, pound, crush and fire up the kiln, I was forced to burn up all the crops that held up the plants in my garden, and then I was forced to burn the tables and the floor of my house. Well, this is quite an extreme form of that struggle of keep what he it shows that he kept trying kept experimenting until he got it absolutely right and was able to make those incredible beautiful plates. But once he gets it right, he says that he wants to keep it a secret. So with my art of the earth and many other arts that is not so for many charming inventions are contaminating and despised because they are too common. Only if I thought you would keep tight the secret of my art as jealously as it deserves would I not hesitate to teach it to you. This in his, this core admirable 1580, very fascinating man and similar live casting was done also in metal. And here you see an example on the left, which is in the Rex Museum of snakes and lizards. And on the right, a beautiful box and writing box from Wenzel Jamnitzer, where all the animals and plants on the outside are live cost. Well, to tell you a little bit more about that, I show you this amazing table ornament. It's a huge piece about a meter high in the Rex Museum. And it has been restored not that long ago, which allowed us to really get closer into contact with this wonderful object. And as you can see at the top here, and at the bottom, there's lots of plants, materials, and all kinds of little animals present. How did they do that? These plants and little lizards, et cetera, are live cost too. And in a recent project called Making and Knowing, Columbia University, wonderful manuscripts in the Bibliothèque de France was discovered. It has been fully transcribed and translated. And you can see everything on the Making and Knowing website. It's absolutely fantastic. But it also contains recipes for live casting. And here you see some details of the plants from the Jamnitzer piece that I showed you. And it's just incredible how beautiful and how detailed that is. And there's also some color here and there added. It's silver and gilded here. And also it's absolutely stunning the detail and how natural it actually looks. Well, to live cost something like that, including also the little animals, and I'll show you an example soon, you need to follow all these recipes that are in that French manuscript. And I'm only going to read a little bit of it, but it is so wonderful and it totally tells you the story. So I haven't gotten in some fat earth called clay that should be gray, because that is the best one, make a lasagne or a pancake shape of this clay equally flattened with a rolling pin, which pastry makers use. There are often connections with cooking in many of these recipes, by the way. And on this pancake, fix your animal, making it as lifelike as possible, and the way in which it is naturally shaped. And firstly, with a good needle, pierce it from underneath in the middle of the throat, up to the top bone of the head. Then take the needle out and in the hole, put a point of an iron wire of such a length that it suffices to maintain the head of the animal as high as it must be. And if the skin gets in, when you put in the wire, take it out with the edge of your small pincer and arrange the skin as it was before. Peace the other ends and so on and so on. It goes arrange afterwards the rest of the body and the legs and the curling as you think will look best. So with little pins, et cetera, you arranged the animal. There's another recipe where it goes in much more detail how to kill the animal and how to pin it live, which I will save you. But on the right, you see a mold with a big beetle, which was already dead. So no animals were damaged for all these recipes, reconstructions that were done in a making and knowing project. And at the bottom, you see the beetle after casting. And of course, that needs a lot of tooling. For little lizards, there is a drawing in the manuscript, as you can see here on the left. And for the reconstructions, they rebuild that in the clay. There's the clay pancake or lasagne, as it was in the recipe. And you see the pins here to pin the animal. Of course, this also was a dead lizard found by one of the team members on their holiday and that was used. And that way, it would be then covered again with clay. The whole thing would go in the kiln. The wax would be melted out and the lizard would evaporate and then you could cast your sulfur. So these are two lizards from that magnificent table piece from Yamnitzer. And they were taken off the piece for cleaning when the piece was restored. And you can already see that they are very, very lifelike, also the way they were shaped. And you have to do that, as the recipe said. And these are details of their skin. And it's amazing, the detail is amazing, because these lizards are about two centimeters thick. So the detail is absolutely stunning. And that is what you can only achieve with these live casts. The skill that that requires is enormous. And that is all described in these recipes. So a beautiful testimony. A lot of the knowledge of these artists was gained also in the 16th century and early 17th century by a sort of interdisciplinary combination of skills. We tend to think in single discipline, so making of engravings, painting, sculpture, goldsmiths work and so on. But we need to think, especially in that period, in a much sort of more interdisciplinary way, and combine all these things. And that also includes the way nature plays a part, the way early modern science plays a part, very connected to artisan ship. And there are these environments at that time. And I want to just give you a taste of that in, for example, in Florence, where in the late 16th century, but running far into the 17th century and early 18th century, under one roof in the Ofici, what is now the Ofici Gallery, and many of you probably have visited that. On the ground floor, there were all kinds of workshops established in 1588, called the Galleria dei Lavori, the gallery of labor of crafts to be better translated. It must have been an absolutely buzzing place, you know, where all these different crafts were together. There's the Italian list here, but you can see painters, sculptures, porcelain makers, jewelers, all kinds of goldsmiths, but also alchemists and glass blowers and so on, and engineers even, and architects, they were all under one roof. And the materials that they used were bought in by one person for all the different workshops. So it was really organized as a sort of, we probably would call it now the creative industries, you know, all under one roof, working together, one sort of conglomerate of knowledge, technical knowledge, artisanal knowledge. And no doubt, there was a lot of exchange between them. This is one of the orders, for example, where materials were bought in. And you see all kinds of materials coming from Spain, from Flanders, for different workshops, the brushes, to pigments, to enamels, etc., including small from Flanders, which I will come back to in a minute. These are two paintings in the Studiolo from Francesco de' Medici in Florence. And it gives you a bit of an idea on how that must have looked. This is the Goldsmiths workshop, the jewelry workshop on the left. And you can see it's big workshop, lots of things happening, masters, apprentices, different techniques, different objects. And here you see kilns, where things were, you know, melted, etc., and of course, the prince would visit to see many princes and dukes, etc., at that time in Italy, would also sometimes participate. That was part of their interest and their education. On the right, you see a glass blowers workshop, the same Studiolo, also a big workshop, also very informative for me as a technical art historian on techniques, on tools and activity and workshop choreography, and all these things, fantastic kind of images. And imagine all these people under one roof, and many, many more, and these are just two professions. And then you get these kind of objects, which is, this is a little tabernacle, it's in Vienna and the Kunsthistorische Museum, and it is from those workshops in Florence. And you can see here the top parts and the columns are rock crystal, that was a separate profession, cutting rock crystal. Then in the background you see the Pietre Dure, so the semi-precious stone and inlay, beautiful sort of mosaic style inlay, that's a separate profession again. All the gold ornaments on it, and also the figures here were definitely made by the gold smiths and the silver smiths, and the enamelers would have done all the enameling. And this, there's fantastic, and I, sorry, I must correct myself, these are actually also made from semi-precious stone, and this is also a semi-precious stone, but the enameling is present here on the small ornamental decorations, as you can see here too. So you have all these different professions working together, creating these amazing objects, which were for the Medici court, almost a Medici brand, but there was also a lot of skill transfer and knowledge exchange, and they pushed each other to be more and more skilled and create new techniques, technical innovation. Well, a bit of history like that, and I mentioned already the smalt from Flanders, is also a nice example of how all these things connect. So I'm now jumping a bit in time, but it's clearly connected with this early period, and I show you this collector's cabinet from the Reich's Museum. It's an absolutely wonderful cabinet where there's all kinds of species of plants and minerals, etc. It's a apothecaries cabinet, if you like, and you see in the middle here this little panel here, showing the pharmacists looking into a bottle, and all these little pots contain something, but they also, the cabinet itself contains many layers with minerals and plant materials, and so beautifully laid out and labeled, and it's absolutely fascinating microcosmos of everything material that was around, and one of the layers contains so-called chemical glass, which turned out to be fragments. So this is the layer, the drawer, and these are these fragments, and they are part of so-called glass cakes, and here you see one from Miotto, a manufacturing company in the early 17th century until the 18th century in Murano, and they made these so-called glass cakes and stamped with their own brands by pouring hot glass, which was specially prepared with a lot of color in it on a metal plate, let it cool down and stamp it, and then you, as an anemolar or a glass maker, could buy these and use them for an anemols. This is just to show you how it's still done, but now they make them square, but they're still working in the same way, and these can be bought for anemols and for glass making, etc. It's absolutely beautiful color. So this anemoling is like painting with glass, and there's, again, a beautiful text about that that explains how to do that, and here you see one of these limorche and anemols from the Rijksmuseum is absolutely stunning colors, but all the colors are made like these glass cakes that I showed you, so you would buy a piece and you would cut it and grind it, and then the ground glass would work like a pigment, and you put a binding medium to it, and you could paint on the copper of the anemol, it would go in the kiln, etc. And this is all described in this treatise by Blancour, which talks about the methods of painting on glass and anemoling, and also how to extract the colors from minerals, metals, herbs, and flowers, and we're containing many secrets and curiosities never before discovered, while most of them claim that, but of course they were trying to really make it very appealing to buy the book or to engage with them, but here you see a detail of that same anemol that I just showed you, and you can see how it is indeed brushstrokes in different colors. It is painting with glass, well that blue contains cobalt, and cobalt containing glass is also a pigment that was used in painting called smalt, and you saw already in that list of materials for the workshops in Florence that they would buy smalt from Flanders, and indeed the Dutch smalt was very, or Netherlandish I should say at that time, was very popular and of a high quality. It's a very complex pigment to make, and one of the things we do in technical art history is that we try to reconstruct things so we can then understand how actually these things work, and if these recipes function or not, and this is a a laboratory reconstruction where all the materials that we find through analysis, scientific analysis, but also through studying all these recipes are laid out, and you see the kiln here, and the little crucibles where you put a mixture of metals in, and fritz that is glass, and then it is being made by this wonderful theme in the University of Lisbon, you can see it's not an easy job, you have to crunch it in water, and then you see immediately the blue color coming up, and now she's trying to separate the blue glass from the crucible, which is not an easy thing to do, but you see the immensely beautiful color, and this is it, this is what they made, smolt, and it replaces one of the most expensive pigments on the palette at the time, ultramarine, which was made of lapis lazuli blue, and lapis lazuli had to be imported all the way from what is now Afghanistan via the Middle East, Venice, where it often was already processed into a pigment, and then to Amsterdam, Antwerp, etc., very, very expensive, and smolt, coming from the glass industry in the 16th century, the glass cakes, as I just showed you, that whole industry was really crucial for this, in the 17th century it becomes a more separate industry where a glass smolt was made for painting, and it's absolutely stunning color, so you can imagine why it was used so much, however, there was a problem, there is a problem with smolt, and I'm showing you here a painting by Joachim Uteval on the left, a annunciation to the shepherds in the Rijksmuseum, it's a very big painting, and a lot of the colors, it seems a bit unbalanced in terms of color, and that is because Uteval used the blue smolts in many areas in this painting, for example this drapery here in the center, it's also part of the drapery, this more pink trousers of the shepherd, the clouds area here around there, there's all smolts in this area as well, and it all has, it's no longer blue, and if you look on the right, this is a cross section, again one of these tiny samples that shows you the layer built up of the painting, this is the ground layer, so it has a brownish ground with a gray on top that you see a lot as a preparation, and then this brown dark stuff is smolt, but it is no longer showing any blue, and on top is a little bit of reddish pink which is taken the sample from this area here, in the ultraviolet light the same sample we can, we often use that so we can see a lot more of the structure, because materials all flourish differently, you can see these particles better of the smolt, and this is a 500 times magnification, so here you see it even better of that area, all these sort of gray particles, very charry like glass charts, they, that is all smolt, but it totally lost its color, and there is a, when you mix smolt with an oil, the fatty acids in the oil impact on the color, it's a very complex process and there's still a lot of research going on to understand exactly what is happening, and that really is problematic, however, I show you another painting, Martin de Fos, Flemish painter, Saint Michael, this painting is in Mexico but painted in Antwerp and then transported to what was then called New Spain, there was a lot of trade going on including paintings, and here you see a beautiful blue and that blue is also smolt, and it is in perfect condition, it's still blue, so what, what is the difference, why is this not, has this not changed, it is also in an oil binding medium, and if you look again at the cross section, these are the last cross sections I'm going to show you, you see the same, the top layer is beautifully blue, there's a bit of lead white mixed in, in this particular area because it was taken in a light area, but in a sample from the dark blue it is just pure smolt and it's blue, but then the layer underneath it that you can see not very well here, murky, darkish, but here you can see it better in the ultraviolet light, there too there is smolt, but that has lost its color, this is still a quite a mystery, so when you try to understand these things, there's a lot of scientific analysis being done, and we can identify the composition of the smolt particles etc, but there is something more going on here, and a very interesting piece of research was done by one of my students in technical art history, Paul van Laar, and he very kindly sharing some information from a paper he's forthcoming, and you know we are actually looking for the master secrets, so grinding smolt is often mentioned in some recipes with an addition of egg white or rabbit skin glue or honey, and so that means that when you grind the pigment to make the particles the right size for the kind of paint you want, very fine or what kind of effect depending on that, you can grind it with water, you can grind it with oil, there are different instructions for different pigments, for smolt you often find certain instructions, but he found recipes where they actually talk about grinding it with smolt with good white honey, each for over an hour, it says this is a recipe from a treatise from 1703 by an Alkmaar painter, a Dutch painter, Simon van Eikkelenberg, and he calls these recipes ervarenissen, experiences, and he talks about using this honey, so Paul van Laar did that, he reconstructed that all, ground the smolt with honey, extensively washed it, so Eikkelenberg said you have to wash it many many times until the water no longer tastes sweet, meaning the honey should be gone, so Paul did that and followed all that and then with the transmission electron microscope, which can create a very high magnification, they looked at those particles and they still found this grayish material here around the particles, they still found honey there, creating a film, and that film seemed to protect maybe those particles from the impact of these fatty acids from the oil, that is a hypothesis, but that is a master secret we're trying to figure out and we will work on that much further, because there is plenty of smolt in the night watch and in many other paintings, so it's a fascinating problem where we combine the text from the recipes with reconstructions and scientific analysis to uncover that secret, so this skill building that I showed you some examples of, maybe some slightly extreme examples, but really hopefully giving you an understanding of how complex these things are, so the skill building, the path to mastery is a concept of hybrid forms of knowledge and working practices, artisans exchange practices with other disciplines and collaborate, it's also talking about innovation driven by competition and changing demands, it's about reinvention of artisanal knowledge, finding new ways to use traditional methods and inventing totally different ways of working with materials or introducing new ones and surviving trajectories of successful practices, which then disseminate through master to apprentice, etc. And I want to finish again with Minerva as the patroness of the art, here you see her again on the front page of Crispijn van der Passes of the light of the art of drawing and painting, published in Amsterdam 1643, you see at her feet the apprentices drawing, and behind her you see a whole range of very well known painters from Utrecht, including Joachim Utevaal of whom we just saw the painting with all the discoloured smalls, he is a part of that, a little bit attention for a well known classic sculpture in the background, and on her lap she has a book of course, one of her symbols, which says Nuladies Sinalinia, never a day without a line, and this is all about drawing and painting, and I think that is a very good closure of this lecture, and finishing with then thanking the sponsors of the Night Watch, and thanking you for your intention, and especially the Royal Philosophical Society of Glasgow and Pat Monaghan for inviting me for presenting this lecture on I hope skills and the wonder and marvel V as researchers feel when we work on this, thank you very much. Question number one is from Ronald Singleton, and he says if an artwork is made of perishable materials that begin to perish, should it be reconstructed by others? Well that's a very good question of course, and a lot of materials in artworks degrade and age in different ways, so many for example in those paintings many pigments are in perfect conditions, many colors are fine, but like the smalls that is this coloring that is a serious you know change, you could just you saw in that painting that the whole balance between colors is then changed, but we don't do anything about that because we can't change that back and it would be not ethical to paint it over if you like, a conservator would never do that, so we need to accept that these things happen. We now often talk about the biography of objects, the life of an object starting at when it was conceived by the artist, the idea and translated into materials up till now maybe 400 years later when we see it and everything that happens in between and that means impact from outside, conservation treatments, changes made in formats and so on, but also inherent to the materials all kinds of aging processes, and unfortunately those aging processes we can't really do anything about, so we will make sure that the painting is stable, the materials are stable, paint doesn't you know get damaged further, but we can't stop that process except you know we do things like UV filters for windows etc to slow it down, the impact of UV for example and so on, lights and so on, but yes unfortunately we would not, we can't do that and we would not do that because it's not something that in conservation is acceptable. Thank you, the next question by somebody who often asks very good questions who names himself or herself anonymous attendee and the question is do modern pigments, it's related to the previous one in a way, how do modern pigments last longer than traditional paintings, traditional paints, pigments? Well some some of them definitely do of course because they they are developed most of, a lot of modern pigments were developed in the 19th century where the industrial revolution and chemistry is developed and let's say synthetic alternatives for traditional pigments are coming on the market, but many in the beginning especially had problems, for example if you look at van Gogh paintings he used a lot of synthetic organic dyes as we call them of red geranium reds and nice names like that which faded quite rapidly and the van Gogh Museum made beautiful reconstruction of the bedroom, the famous bedroom of van Gogh where that color red has gone and when they virtually added to it it totally changed the whole painting because then it you know you could see the different tones so yes a lot of these pigments also have had problems but they're still newer ones coming on the market and of course painters stopped using them because they quickly became aware of the unstable character of these pigments so there are many traditional pigments like earth pigments for example that are super stable they will they don't change at all so it's a mixture of you know some quite a lot of the traditional pigments are very stable and a lot of modern variations are very stable but there have been problems as well yes with modern inventions if you like. Thank you so if I may ask a question related to that if a painting needs restoration and somebody has damaged it or it's been left in ultraviolet exposed ultraviolet light do you do conservators try and use the original or a modern equivalent? For for example for retouching losses we well I no longer work as a conservator of course but conservators would use first of all a layer in between the original paints and what you're going to add like they call it a retouching varnish very thin layer so that there's always a distinction and then you would use yes modern pigments you could use modern pigments because many of them are stable but also like earth pigments that are traditional ones and they never have been replaced because they are you know in abundance available and and very good quality so it's usually a mixture. Thank you for anyone who's interested in the carbon robots gallery there I haven't been there in recent weeks obviously but there's a wonderful painting by an artist Gray a lady artist which is partially restored and you can see some of the dirt cleaned up it's really very interesting anyway next question is by Dulles Carter did any of the apprentices decide to specialise in making of paints and in other artistic materials instead of being painters making up the materials seem to be a very specialised skill in itself and I presume must have been very time consuming. Yes so in the in the 16th and 17th century especially in the 16th century there were a lot of recipes in those treatises where they explain how to make certain pigments and that can be incredibly complicated and also very toxic in some cases so not easy so quickly there were people specialising in doing that and many of the pigments were then sold through for example a protechories so that's where you would go as a painter to to buy your materials so there were specialists making them and you find all kinds of special places like in Amsterdam outside of Amsterdam you had the so-called paint mills where they were grinding in the mill this driven by power from the mill they had a special room to grind pigments that were actually quite toxic so that the dust could not come out of the room so they were aware of these things and that was outside of the city you wouldn't build something like that inside so there were all kinds of specialists and of course in the 19th century you get all these new pigments etc and then you get paints that are actually prepared including the oil and everything in tubes but that's only from 1840 onwards then that's the daily paint tube was invented up till then that's all they all would still make their own paints but they would buy the raw materials the pigments already made yeah I was very impressed by how and developed the industry in a sense the art industry was in those times all those years ago there must have been you know a whole system and and a market for these very expensive things so to have this must have been culturally was there you know I believe that there was a time in Holland in the Netherlands when people had money because it was a very successful trading nation but because of the nature of the society very conservative society people had artworks inside instead of showy wealth outside to that sort of thing influence the market at all of the things that you were talking about in the era you were talking about well I think in the Netherlands and especially in the northern Netherlands there was a very much a merchantile society and everybody had paintings and the market so painters worked for all kinds of echelons of the society if you like very expensive pieces to more of mainstream depending for you know where they it was very market driven and and those things have an enormous impact on techniques and materials because when landscapes became very popular there was a new style of painting landscapes which was really fast and very quick in but very effective and very beautiful and it it was it made it possible to produce a huge number of paintings and to serve that market demand right so you it's very important it's a very good point that you make because you always have to put these things in perspective and you cannot just study a for example the new technique that suddenly arrives without looking into the environment around it why why is this technique there and you always find your answers in the environment the society the trade what was available what was the market demand all these things come together and that's really important thank you Keith McDonald asked well it's he assumes that the art science and technology work together and improves our culture how could we encourage that today an easy question isn't it that's that's not such an easy question I mean that's all about interdisciplinarity and cross-discipline and multi-discipline I mean it's what we all in academia too talk about a lot I think from my experience working with others is usually well for me it's very important and it really broadens my horizon enormously and I learn a lot from scientists and the way they think and the way they look at things and they say the same to me when we're talking about art research of course technical research and and it's fascinating to to do that but I think you still need to be able to really be thorough in your own fields and in your own discipline it's a bit like somebody called it a t-shaped researcher so the the vertical of the t is your disciplinary you know your one discipline you go into depth but your the horizontal bar of the t is this broad reaching out to other disciplines and I think that is a very nice symbol of how it enriches your understanding of what's going on and I do think without that you do miss a more thorough and more broad and more you know based on the world very in interpretation and Wendy service and or her husband and is asks is there any crossover between rediscovery of techniques of glass-based paint and the study of stained glass in particular the method of production of some early blue stained glass absolutely yes yes yes there are more crossovers than I showed in that in the in the talk because I I only and I already went over time I think so you know but there there are definitely yes stained glass the coloring of stained glass it all hangs together it all connects together absolutely I mean another thing that I didn't mention is that in the recipe books you find a lot of recipes to make fake gems including sapphires the blue sapphires and that is again glass and that is again blue glass cobalt glass etc so all these things these small tea these smalls that are mentioned in priceless etc are also used for stained glass as well that is that's a good point yeah thank you um whoops questions are jumping around a bit yeah do conservationists work on restoring their own areas of specialty in other words does somebody work on insect wings and other on plants or does the subject matter less matter less than the original painter so does somebody stick with a painter or go with elements of their painting this is from our anonymous attendee friend well it's a very good question um in the rex museum for example we have under one roof we have quite a lot of different studios so glass, paper, ceramics, paintings, furniture etc and there's lots of collaboration so if an object has sort of let's say mixed media so different materials then we do yeah do you see colleagues that they go and ask another expert because every one of those colleagues is an expert in their own fields so but with the the the wings of the butterflies that's of course a different story because I don't think anybody is an expert in conservation in that except maybe people who work on natural history objects like butterflies and you know other natural history objects so it would make full sense to talk to them and I started that conversation about how in that period of time would they preserve butterfly wings and is there a method there that this particular painter Otto Marseille von Schrieck could have used or you know to transfer these scales of these wings to the painting sticking them in the varnish and then removing the membrane leaving the scales behind it seems so incredibly difficult there must have been a method that was easier for him and maybe that comes from so maybe he already I'm sure actually he talked to specialists at the time experts at the time and inserted that then in his paintings and and we should do that too we should definitely do that too yeah the next question and we're actually running a little out of time but I think we'll get some of them in would pigments and cutters used by Dutch artists to be used throughout Europe or was the regional variation from anonymous attendee can you can you repeat that would it was they were the pigments used by Dutch artists the same throughout Europe or were ah yeah okay the variation well you do find some local things for example if organic pigments that are made from plants for example that especially in watercolor or manuscript illumination you do find sometimes that artist working in a particular area would use local local plants which would grow let's say in southern Europe but not in the north for example but most most of the inorganic pigments so like earths and so on were available throughout Europe and there they can be manufactured locally and there might be a specialist like small from Flanders as you saw in that list from Florence so clearly there must have been a specialist there a manufacturer of an industry that produced very high quality and then it would be imported to Florence in the late 16th century to be used there you know but in principle they they had very similar use of pigments and these pigments let's say traveled so there was trades all over Europe yeah I think there's one last question and I apologize for not being able to cover all the others but and this one I think you've actually touched on before so you may not it may not be too long to answer the the Robert Thompson asks if the paintings where blue has faded so badly can it is there a point where it really can't be restored or where it's too dangerous to the paintings integrity to try and restore yes if a if a pigment fades or discolors or we don't but as long as the paint layer is stable so not let's say cracking and flaking but it's it's stable we would not touch it that's the short answer and we would accept we would accept that the color is gone as you saw in that painting that I showed you from Ute Waal a lot of the small test discolored and that's how it is on display well I think we'll have to end the questions there but thank you very much for the most interesting lecture I didn't really know what to expect and I suspect I may not have been the only one to know the journey of a painting or an artwork from inspiration where they've got their utensils and their elements their pigments how they actually crafted things and how you can analyze that today what to make of it philosophy of restoring the limits and I bet there's a lot more of the science that you could have blinded us with tonight and various forms of analysis but for another day perhaps so I'm sure you you'll realize I could have spoken I have spoken for many more hours I know I know and I think we would have enjoyed that anyhow but thank you so very much and I'm just going to try and see if I can screen share now huh right so this is as Burma mentioned earlier the Minerva lecture and when the philosophical society was initially started about 300 years ago and it was started as a way of promoting science and arts and there was an arts medal at one stage but it wasn't a named medal and they wanted to give it equal prestige to the Kelvin medal and so on so Minerva was chosen because there's a link with Minerva it Minerva is the original membership certificates of the society were stamped with this stamp on the left this is the name of the book it came from it's misfired in foreign history and it's also on the rear of the back rest of the master's chair which is safely I believe in Strathclyde University and Minerva being the Roman goddess as I mentioned of wisdom and I've had we'll we'll skip over one or two aspects of her skills and remit which is very wide but sponsor of the arts crafts and more so I think we've been treated tonight to a most wonderful lecture covering elements of the art that we may not have known anything about or not have realized painted glass paint and so on and a hint of the vast scientific contribution to this so thank you very much Burma and this is a picture of the medal that will be posted to you and it's to recognize your contribution to the society in your skill in your knowledge of the arts so thank you very much thank you very much very welcome and thank you very much for the invitation