The Fire and the Furnace: Making Recipes Work

By Thijs Hagendijk

While working on the Ars Vitraria Experimentalis (1678), the principle book on seventeenth-century glass, I came a across a peculiar remark. The author of the book, the German alchemist and glassmaker Johann Kunckel (1630-1703) composed a commentary on a series of Italian glaze recipes, and somewhere along he dropped the following line: “reproducing this glaze requires as much Art as inventing it” (p. 193). I was struck by this remark and have been thinking about it ever since. What is it that Kunckel tried to tell us here? What does it tell us about recipes, these miraculously concise pieces of text? And how do these written instructions fit into workshop practices? After all, when reproducing a recipe becomes an investment that equals its invention from scratch – why bother with books at all?

That people bothered is in fact beyond dispute. Recipe research from the past years has come up with ample reasons why people engaged with practical texts. People were working on their reputation, tried to organize experiential knowledge, or were concerned about the epistemic status of their crafts. And indeed, all these elements instantly return in Kunckel’s Ars Vitraria Experimentalis. Kunckel is particularly keen on stressing that everything in his book has been vetted through experience. His book reads as an attempt to apply for a good position at the Brandenburg court, and he openly runs down his main competitor, Friedrich Geißler, who worked on a similar book project. “Lieber Herr Geißler, I am sorry that you are so utterly unfortunate in your judgments and comments” (p. 188). In the end, however, we should not forget that the Ars Vitraria Experimentalis was born out of practice. It finds its basis in the workshop, amidst the radiant heat of furnaces, brightly glowing glass, skilled labor and the stinging smell of smoke.

Back to the glaze recipes. While the Italian glassmaker Antonio Neri (1576-1614) originally conceived the glass recipes some seventy years earlier, Kunckel now presented a German translation of these recipes, lavishly annotated with his comments. In an attempt to better understand how this concoction of recipes and commentaries would fit into actual workshop practices, I teamed up with Márcia Vilargiues (Universidade NOVA de Lisboa) and Sven Dupré (Utrecht University) to rework a couple of recipes. We gathered and prepared the ingredients and spent days around furnaces trying to reproduce the recipes.

Figure 1. One of the wood-fired furnaces we used to reproduce the glaze recipes. Note that the fire is stoked from the sides. Location: Telheiro da Encosta do Castelo, Montemor-o-Novo, Portugal.

We dragged wood, stoked furnaces and patiently waited for the heat to come. We tried to control the smoke and played games guessing temperatures from different shades of bright orange. Showers at the end of the day invariably turned my white bathtub into a deep brown. During these days, our main occupation was fire. Ingredients for the glaze, their quantities and the order in which they had to be combined became mere side issues.

Figure 2. The furnace opening was closed with bricks to keep in the heat. Bricks were only temporarily removed to move samples.

It was in this smoky atmosphere that we began to see a fundamental characteristic of Kunckel’s commentary. The focus of commentaries, annotations and marginalia in practical texts had traditionally been the testing, correcting and improving of recipes, but Kunckel took a slightly different approach. He started to dress up Neri’s recipes in his commentary and added new and previously unarticulated layers to the original recipes. What layers? Well, think for instance about the role of fire. While Neri straightforwardly communicated ingredients, ratios and the different steps in his glaze recipes, nothing prepared us for the important task that fire management turned out to be, which went far beyond sending some wood up in flames. Kunckel, on the contrary, emphasizes this very issue in his commentary, and repeatedly argues that “the Fire is the principle thing to observe” (p. 194).

Figure 3. To work efficiently, we reproduced several recipes at once.

Indeed, while working with different furnaces, we learned that furnaces are more than simple and inert providers of heat. Instead, wood-fired furnaces become a tool by which the quality of the glass is shaped in addition to the ingredients and the quantities prescribed by the recipe. Temperature, atmosphere and position in the furnace are all partly responsible for the end result. In the end, reworking the same recipe in three different furnaces left us with three sets of glazes in different qualities. See how Kunckel cleverly shifted the perspective in Neri’s recipes? Kunckel made his readers aware of the circumstances they had to navigate when putting a recipe into practice, something for which Neri left them unprepared.

Figure 4. Two samples of the red roischiero glaze.

Making processes can be understood as processes of growth, the anthropologist Tim Ingold tells us. And this stance on making has significant consequences for how we understand the position of texts in these processes. Makers stand in an ecological relation with their environment, their materials, tools, and the forces they work with. To make a glaze means that the molten glass, the furnace, the smoke, etc. act in correspondence with an observant and anticipating glassmaker. Crucially important here is that ideas, designs or written instructions cannot simply be imposed onto reality. Recipes need to become part of it instead. To make something means to adapt and respond to the local and unique joining and intertwining of forces, materials and elements – and written instructions form just one strand in this creative process. Seen in this light, Kunckel’s remark was not so much a pessimistic note on the possibly superfluous nature of glaze recipes, but rather a reminder that reading and reproducing a recipe is an all-encompassing effort to make the recipe work in the unique constellation of the individual workshop. Reproducing a recipe is reinventing the wheel.

Thijs Hagendijk is a lecturer at Utrecht University. Earlier this year, he defended his dissertation on reading and writing practices in the early modern arts, with a specific focus on text usage in historical glassmaking, painting and metalworking. He works on the intersection of technical art history and the history of chemistry, and is interested in performative methods, such as reworking, re-enacting and reproducing historical techniques, materials and processes.

*You can read more about this project in Thijs’ recent article in Ambix.

Variable Matters (Basel, 20-22 September 2019), organized by Barbara Orland and Stefanie Gänger

By Stefanie Gänger

Hosted at Basel’s beautiful Pharmacy Museum, the conference “Variable Matters” was designed to bring together historians with an interest in the movement of medicinals and knowledge about them between and across societies in the world of the ‘long’ eighteenth century. Participants talked about very different kinds of substances – vanilla, calomel, bezoars – and studied them in rather diverse contexts – anything from the Swiss Alps to the Bolivian Andes – but everyone was reflecting, in one way or another, on the subjects of medicine trade, therapeutic exchange, and epistemic brokerage.

Several speakers engaged with one or another aspect of the communication of medical knowledge about foreign or unfamiliar ‘simples’ to other cultural imaginaries, medical localities, and therapeutic traditions. Quite a few papers dealt with the acquisition, transfer and codification of remedies associated with the ‘exotic’. Emma Spary, in a public keynote lecture, discussed the introduction of vanilla to France. Vanilla, originally from the Spanish Viceroyalty of New Spain, was becoming familiar in France from the late 1600s, and the talk focused on the various issues – of translation, transport, and taste – involved in moving the plant and knowledge about it across vast expanses of space. In another paper, we heard about the growing consumption of tea in the seventeenth-and eighteenth-century Low Countries from Marieke Hendriksen, who was just starting a new project on the role of subjective experience and taste in the acquisition and communication of knowledge about ‘new’, exotic materia medica. Hjalmar Fors’ talk, in turn, discussed the constraints that Europeans operated under in their encounter with ‘exotic’ plants more broadly – what they deemed worth knowing, or valuable about them, on account of those constraints – and on the botanical and (al-)chemical practices that would reduce them to a semblance of – European – order.

The delegates of the conference

Other papers discussed the acquisition, transfer and codification of remedies associated with the ancient, or artisanal. Francesco Luzzini spoke of the Italian physician and naturalist Antonio Vallisneri’s interest in ‘popular’ therapeutics, including his inquiries into the mineral remedies in use among miners, and artisans. Laurence Totelin, in turn, talked about the reception and critique of ancient antidotes like mithridatium and theriac in the eighteenth century, through treatises like William Heberden’s 1745 Antitheriaca. Heberden also figured in other talks, especially in Chris Duffin’s, which explored the contents of eighteenth-century medical chests – including Heberden’s teaching cabinet – that encompassed anything from Mesoamerican cochineal to album graecum.

Other papers engaged with the relationship between homegrown, or ‘indigenous’, medicines and novel, unfamiliar substances. Silvia Flubacher, in a paper co-authored with Simona Boscani, talked about the eighteenth-century market in ‘German bezoars’ extracted from Swiss chamois, or goats, a medical commodity that emerged in reaction to overprized exotic bezoars, as part of a discursive revaluation of the ‘local’. Other speakers engaged with ‘their’ substances’ ontological instability, the many acts of adaptation, customizing and calibration a medical substance’s journeys might entail. Irina Podgorny’s talk in particular, focusing on the example of eagle stones – hollow geode stones worn as amulets with a longstanding reputation for protecting pregnant women, or comforting women grieving the loss of a child – discussed not only shifts in the stones’ nomenclature and therapeutic indications as they travelled from Europe to Spanish America; it also studied how the very name – ‘eagle stone’ – was transferred to various objects that were concomitantly attributed analogous properties: to American fossils, and pietists collections of prayers alike.

Other speakers focused on the formats used to convey medical knowledge. Clare Griffin presented a paper on the gradual incorporation of American herbal medicines into Russian recipes over the seventeenth and eighteenth centuries, while Matthew J. Eddy delivered a paper on a series of medical consultation letters between the prominent Edinburgh physician William Cullen and a Quaker woman, and the ensuing give-and-take of their negotiations over the proper medicines. Sabrina Minuzzi’s paper, in turn, studied the correspondence and publications – cheap pamphlets, in the majority – of Johannes Behm (c. 1640–1731), or Giovanni Beni, a physician, plant collector and broker who moved knowledge about medicinals and therapeutic practices around, especially between northern and southern Europe, but also with the East Indies, owing to his contacts with merchants, plant traders and botanists alike.

The Basel Pharmacy Museum.

In-between papers, we had the privilege of a guided tour of the Pharmacy Museum by the organizer, Barbara Orland, and the museum’s acting director, Philippe Wanner, who did their very best guiding a bunch of excited specialists through the collection (what with everyone chatting excitedly, and constantly getting side-tracked, by charred monkey skulls, preserved seahorses, or actual eagle stones!).

Experiencing Historical Techniques through the Color Black at the ROOHTS Summer School

By Sharifa Lookman

As October draws to a close, we feature yet another exciting article from our ongoing series of cross-postings on the hands-on, collaborative research project into recipes for Burgundian Black, organized by Dr. Jenny Boulboullé. Today, Sharifa Lookman provides another fascinating peek into the inner workings of the project (Joshua Schlachet)

For the pre-modern artist, color was anything but random. As both concept and product, it wore many masks: the bearer of symbolic significance, an agent of trade, and a protagonist in histories of politics, economy, and geography. In material, it was the hard-earned product of natural ingredients and arcane, even alchemical processes. Researchers in the Faculty of Design Sciences and the working group ROOHTS (Research on the Origin of Historical Techniques) at the University of Antwerp have returned to historical recipes to investigate these aspects of color. From July 1-5, in collaboration with the ARTECHNE ERC research group at the University of Utrecht, researchers took up the following question: how did pre-modern colorists perceive, manufacture, and master the color black?

The intensive, five-day summer school, “Burgundian Blacks,” brought together artists, scholars, and scientists of diverse backgrounds to investigate black color technologies of multiple media, working from the production of black textile dyes (the focus of a January workshop, the Burgundian Black Collaboratory) and moving into adjacent practices used to produce black inks and paints in and around the historic region of Burgundy. Each day consisted of a theoretical component and a practical one: classes moved back and forth between the lecture hall, with studies on historical contexts, and the laboratory, where recipes were tested through experimental reconstructions, or (re)enactments.

The setting—a university conservation laboratory—was decidedly ahistorical and acknowledged the inherent limits of reconstruction: small sample sizes and anachronistic instruments, for starters. And yet, when all thirteen of the participants and a handful of instructors were in the lab together, we more or less simulated an active ‘workshop,’ complete with masters and apprentices, back-and-forth shop talk, and bustling bodies (Fig. 1). As a participant, I found that the summer school’s give-and-take between the written word and re-enactment emphasized two fundamental ideas in the study of color technologies: the mutability of language in interpreting recipes and the intellectual merit of touch and sensation in reconstructing them; in other words, the valuable cross-fertilization of both mind and body in materiality studies.[i]

Figure 1: Laboratory space in the University of Antwerp conservation labs.


In considering early modern writings on color, twenty-first century scholars must first be acquainted with an author’s vocabulary, biases, and technical ‘know-how.’ This was the case in our workshop reconstruction of “Noir de Flandres” (Black of Flanders), a seventeenth-century French recipe for a madder and woad-based dye. Here the compiler of the recipe added in his own hand, “And you will have a perfect and durable black” (Fig. 2).[ii] What, according to our writer, is a ‘perfect black,’ and how did it relate to other early modern colors? Over the course of our two-day dye session we produced a number of dyed textiles, many in various shades of black and others not black at all (Fig. 3). Were any of them ‘perfect?’ We often struggled with terms to describe this range, using words such as ‘fresh,’ ‘saturated,’ or ‘opaque.’ But are these the terms an early modern colorist would use? Our author does tell us that, in addition to being ‘perfect,’ the Noir de Flandres is also ‘durable,’ implying that, even in the moment of its making, it was important that the color last for posterity.

Figure 2: “Noir de Flandres” recipe manuscript with compilers annotation: “Vous aurés un noir parfaict & durable.” Image courtesy of the Royal Society Archives.
Figure 3: Dying linen using gallnuts; Left: Whole gallnuts; Center: Washing unbleached linen after first dye bath; Right: Cooking unbleached linen in second dye bath.

Knowledge of materials, processes, and techniques was also gleaned from sources that were not written down, namely ‘shop talk,’ a kind of knowledge circulated within and across artist workshops. Though the dye recipes we tested ranged in time period (1350-1670) and geography, they often shared ingredients. By analyzing the presence and absence of certain ingredients in black dye recipes, scholars, such as Natalia Ortega-Saez of the University of Antwerp, have classified these recipes into three main groups.[iii] Based on these, a twenty-first century reader can effectively ‘fill in the gaps’ when information in the original transcription of one particular recipe is missing or unclear. Likely, a contemporary would have done just that, having considered particular instructions to be common knowledge. We might think back to the Italian artist and writer Giorgio Vasari who, describing fourteenth-century artist Cennino Cennini’s treatise on painting, wrote, “[Cennini] was anxious to know the peculiarities of colors … and gave much advice which I need not expand upon, since all these matters, which he then considered very great secrets, are now universally known.”[iv] By the sixteenth century certain materials and their properties must have been widely known across Europe, and the disappearance of these procedures in writing suggests that this information was not forgotten, but instead circulated verbally, just as we shared and transmitted knowledge orally in the laboratory.


Where our dye reconstructions were much more ‘experimental,’ some recipes being deciphered and tested for the very first time, our pigment recipes had comparatively fewer unknowns. Instead, we were encouraged to consider the appearance, smell, and feel of our materials as we progressed through the recipes. Simply put, we shifted away from the written and spoken word and towards the sensory experience of color production. We began by roasting our raw ingredients—primarily animal bones and fruit pits—in crucibles in an open flame (Fig. 4). The goal here was to char the materials just until they turned black; too long on the flame risks turning the bones white, the base for another color, ‘bone-white.’

Figure 4: Roasting materials for pigments; Left: Peach and cherry pits pre-fire; Center: Crushed bovine bone in crucibile, pre-fire; Right: Crucible in flame.

The body took centerstage as we began grinding our pigments. Organic materials, like fruit stones and plant matter, broke down in mere minutes, but sheep and bovine bones were significantly denser and more difficult, some requiring twenty to thirty minutes of continuous grinding. To achieve the kind of fine powder necessary for high-quality pigments, one clearly needed strength and dexterity as well as a cultivated sensitivity to natural materials. Without time specifications in our recipes, we ground our pigments until they felt finely powdered, and mulled them with water until we could no longer feel or hear granules sliding between the glass (Fig. 5). Sensory indicators—touch, smell, and sight—developed into an acquired “skilled vision” and “expert touch” akin to shop talk, one that filled gaps in reasoning.[v]

Figure 5: Grinding pigments; Top left: Mortar and pestle to grind charred matter; Top right: Ground color; Bottom left: Mulling ground color with water to further break down particles; Bottom right: Final result for vine black.

We considered these ideas even further by applying the pigments to paper: how did the paint feel when applied? What was its texture? Translucency? Facture? Here the term ‘body’ can be dually defined. In addition to referring to the body of the maker, it also suggests the ‘body’ of a color, as Jenny Boulboullé of the University of Utrecht has observed.[vi] The coloristic effects, success, and ‘body’ of our black pigments were not only dependent on its raw material and how we processed it, but also the type of binding medium used; depending on this, a color’s transparency, density, and quality differed considerably (Fig. 6). Because we used only water and gum arabic as binders, I couldn’t help but wonder how, precisely, the choice of binder can modulate the color black. In other words, to quote Ann-Sophie Lehmann, in mixing and applying pigment, what is the “matter of the medium?”[vii]

Figure 6: Left: Page from sample book produced during the workshop; Upper right: Two samples of Vine black, one with a water binder (left) and the other a binding mixture of water and gum arabic (right); Center right: Cherry stone black. We did not grind the cherry stones into a sufficiently fine powder and, because of this, the resulting pigment had a grainy, irregular consistency; Lower right; Stick lac black. In this sample I bound the stick lac in gum arabic with very little water. The result was a tacky paint that congealed when applied to paper.

Re-enactments of historical techniques bring to the surface ideas that are often latent in strictly theoretical approaches to technique and materiality. By investigating recipes for pre-modern black, we engage with color as both technique and concept, as the cross-geographical product of nature and artistic experimentalism, and, above all, as an area of study that has increasingly come to move across disciplines and scholarly domains.


[i] See Sven Dupré’s blog post, “Re-enactment in Teaching Art History (Part 1),”

[ii] Original French: “un noir parfaict & durable.” Recipe transcribed and translated by Jenny Boulboullé.

[iii] Natalia Ortega Saez, Ina Vanden Berghe, Olivier Schalm, et al., “Material analysis versus historical dye recipes: ingredients found in black dyed wool from five Belgian archives (1650-1850),” Conservar Património 31 (2019): 1-18.

[iv] Giorgio Vasari, “Vita di Agnolo Gaddi,” in Le vite de’ più eccellenti pittori, scultori, e architettori, nelle redazioni del 1550 e 1568, Vol. 2 [1568], eds. Paola Barocchi and Rosanna Bettarini, 6 vols. (Florence: Sansoni Editore, 1966-87), 248-9; for translation see Angela Cerasuolo, Literature and Artistic Practice in Sixteenth-Century Italy, trans. Helen Glanville, ed. Walter S. Melion (Leiden: Brill Publishing, 2017), 173.

[v] Cristina Grasseni, Skilled Visions: Between Apprenticeship and Standards (New York, NY: Berghahn Books, 2007).

[vi] Jenny Boulboullé and Maartie Stols-Witlox consider these themes in an essay entitled, “Working (with) the corps: bodies of colours, sands and varnishes in Ms Fr. 640 and MS 2052,” which will be published in the forthcoming Critical Edition of Bnf Ms Fr 640, edited by Pamela Smith & the Making and Knowing Project.

[vii] Ann-Sophie Lehmann, “The matter of the medium: some tools for an art-theoretical interpretation of materials,” in The Matter of Art: Materials, Practices, Cultural Logics, c. 1250-1750, eds. Christy Anderson, Anne Dunlop and Pamela H. Smith (Manchester: Manchester University Press, 2014), 21-41.

Exploring Historical Blacks: The Burgundian Black Collaboratory

By Paula Hohti

Here at The Recipes Project, we are proud to have the opportunity to, from time to time, amplify the incredible collaborative projects of our contributors by cross-posting their work in their own words. This is the first entry in a series of posts on collaborative research into recipes for Burgundian Black, organized by Dr. Jenny Boulboullé. We look forward to sharing more from their project throughout the month to come. This post is reproduced from their entry at Refashioning the Renaissance on February 21st, 2019. (Joshua Schlachet)

Last month, I participated in a workshop on historical black dyes in the Netherlands, titled “Burgundian Black Collaboratory.” co-organised by Jenny Boulboullè from the ERC ARTECHNE Research group and Claudy Jongstra—a talented and creative textile artist working on historical wool fibres and natural dyes—in collaboration with Natalia Ortega-Saez, and the Museum Hof van Busleyden.  Led by Jenny and hosted by Claudy on her farm in Hùns, I and the rest of the group spent three days in a green house in the Dutch countryside, trying out recipes and testing how ‘a perfect Burgundian black,’ once seen as the utmost civic and professional colour, could be created by using historical dye recipes. The aim of the workshop was to provide material for the planned exhibition at the Museum Hof van Busleyden, and an e-book project, edited by Jenny Boulboullé and Sven Dupré.

Black is the most difficult colour to dye, because it washes out easily and degrades faster than other colours. Given the complexity and expense related to dyeing black, historical recipe books are full of black dye recipes, from simple and cheap procedures that could be applied by men and women at home to complex and expensive recipes that required professional skill and economic capital.

In the ‘Burgundian Black Collaboratory,’ we worked in groups to test these recipes, using Flemish and Italian sources, including the Venetian Plichto by Rosetti (1548), which is the first known book of dye recipes intended for professional dyers. This allowed us both to explore the process and methodology of reconstructing historical recipes (the recipes are vague and rarely include accurate measures!) as well as to evaluate how well the original recipe might have worked in terms of creating black.

Black was traditionally produced from barks and roots that contain tannins (such as alder, walnut and chestnut). To provide a colour that stayed longer, dyers started combining tannins with iron salts that acted as a mordant. This produced a more beautiful black, but the result was corrosive to the fabric.

A better -but much more expensive and complicated – way to achieve black colour was to use a madder and woad base overdyed with tannins such as gall nuts. By the late sixteenth century, the best-known method to get a beautiful, deep black was to dip the silk or wool first in either a woad or indigo bath that gave the cloth a beautiful blue undertone, and then, when the fabric was dry, to overdye the fabric with madder (red dye) on an alum mordant.

The challenges of reconstruction, and the great differences between recipes of black, became well visualized and materialised in the results.  Some did not turn black at all, others were initially black but turned brown overnight when they were dry, while others were just beautifully deep black. These differences were due to the fact that some recipes did not provide as precise instructions as others, they were misleading, or they simply did not work.

The fascination and interest of dyers over black reflects the fact that black was an ultimate colour of power, status and fashion in early modern Europe. By the end of sixteenth century, it was essential for young men of wealthy families to have their portraits painted in black.  

Although deep, sumptuous blacks with blue, purple or red undertones are usually associated only with the elites and merchant classes, black was, in fact, the most important colour also in clothing of our ordinary artisans and shopkeepers.  Our initial data shows that, for example in Siena between 1550–1650, whenever colour was mentioned, 25% of all male and female clothing consisted of garments dyed with different types of blacks, including jackets, breeches, over-gowns among others.

Recipes for dyeing black, intended for domestic use by ordinary people, were available also for our artisan groups through cheap printed pamphlets and booklets that were sold at a cheap price by, for example, street peddlers. One of the recurring recipes for home-based black dyeing, described ‘for women after they have spun their yarn,’ was prepared by boiling oak gall with a small amount of copper sulphate and Arabic gum -the latter which was added to give the black a degree of lustre. While this might have produced a reasonably beautiful black colour, the copper made the woollen yarn weak. For this reason, professional wool dyers, at least in Venice, were forbidden by their guild to use this method.

We will be experimenting with the Refashioning the Renaissance team with domestic dyeing and colour, and investigating what kinds of blacks among other colours our artisans wore, what these looked like and how durable these were.

Please keep an eye on Michele’s talk and article on how to use printed sources as evidence for the history of lower-class dress, on Sophie’s dye experiment during our trip to Columbia University’s Making and Knowing Project, and my forthcoming articles on Colour, on red dyes, and the social and culture meanings of black in sixteenth and seventeenth century European fashions.


Susan Kay-Williams, The Story of Colour in Textiles: Imperial Purple to Denim Blue (Bloomsbury, 2013).

Natalia Ortega Saez, Black dyed wool in North Western Europe 1680- 1850: The relationship between Historical Recipes and the Current state of preservation (unpublished PhD. dissertation submitted for University of Antwerpen, 2018).

Dominique Cardon, Natural Dyes: Sources, Tradition, Technology and Science (Archetype Publications, 2003).

Elizabeth Currie, Fashion and Masculinity in Renaissance Florence (Bloomsbury, 2016).

Riikka Räisänenm Anja Primetta, Kirsi Niinimäki, Luonnonväriaineet (Maahenki 2015).