The ChromAz project tells the story of sixteenth- to eighteenth-century Portuguese azulejos from the perspective of colour technology. Tiles are a crucial piece of Portuguese national heritage, and artists had a broad palette of colours at their disposal. We started with one of the most complex to achieve: a pigment known as Naples yellow (lead antimonate), a product of human craft with a long history.
As one of the very first artificial materials, Naples yellow was employed from the Late Bronze Age (ca. 1500 BC) and initially linked to the production of opaque yellow glass. After disappearing from the European tradition for over a millennium, the pigment resurfaced in the sixteenth century, used by Venetian glassmakers, in oil paintings and in decorated glazed ceramics.
Around this time, technical texts begin to feature recipes for the manufacture of Naples yellow. Besides the lead-antimony base, authors list a number of other reagents, but only vaguely (if at all) describe the chromatic effects brought by the additions of these ingredients. So, to gain insights into such an important aspect of the early modern artistic process, we replicated eight recipes, summarised in Table 1.
Four recipes (Mariani I and II, Piccolpasso and Marmi 126) are simple, binary lead antimonates to which salt or tartar (or both) were added as fluxes to facilitate the reaction. The remaining four (Mariani III, Marmi 136, Darduin and Danzica) are ternary variants of the pigment. They can come with or without fluxes but, importantly, they contain what the authors refer to as tutty or tuccia, which scholars have variably interpreted as either zinc or tin oxide. To evaluate differences, we made two sets, one with the former and one with the latter, bringing the total to twelve re-worked recipes.
After thoroughly mixing the ingredients, we fired the raw pigments at 950°C for five hours and left them in the furnace to cool down to room temperature. Finally, we collected the mixtures, which had turned yellow, and ground them to a fine powder to homogenise the colour (Figure 2).
As the images show, variations in the recipes resulted in remarkably different hues, ranging from pale to bright yellow and all the way to dark orange. Adding zinc tends to darken the colour, while tin makes it lighter, as previous works already indicated (Figure 3A). The one yellow with calcina (lead and tin calcined together) is also made somewhat paler, due to the action of tin (Figure 3B).
However, it was more interesting to find out that fluxes have an equally crucial role in defining the chromatic characteristics of the pigment. We found out that salt invariably makes the pigment lighter in colour. On the other hand, the recipes containing tartar as the main flux display a darker, reddish hue (Figure 4).
Re-working lead antimonate recipes provided access to the wide chromatic palette that Renaissance artists could rely on. The pigment could be adjusted to be proper yellow or more orange-red, depending on users’ needs. Importantly, this flexibility also meant that recipes could be tweaked to accommodate issues of materials’ availability. Our work is still very much in progress, but it shows how performative methods complement information from texts and material culture and give them new context, throwing more decisive light on the act of art-making in the past.
Dik, J., Hermens, E., Peschar, R. and Schenk, H. “Early production recipes for lead antimonate yellow in Italian art”, Archaeometry 47, 3 (2005): 593-607.
Hermens, E. “A seventeenth-century Italian treatise on miniature painting and its author(s)”, in A. Wallert, E. Hermens and M. Peek (eds), Historical painting techniques, materials and studio practice: preprints of a symposium, University of Leiden, the Netherlands, 26–29 June 1995. Marina Del Rey (CA): Getty Conservation Institute, 1995: 48–57.
Marmi, D. The Ceramist’s Secrets. Edited by Fausto Berti. Translated with an introductory note by David P. Bénéteau. Montelupo Fiorentino: Aedo, 2005.
Moretti, C., Salerno, C.S. and Tommasi Ferroni, S. Ricette Vetrarie Muranesi. Gasparo Brunoro e il Manoscritto di Danzica. Firenze: Nardini Editore, 2004.
Piccolpasso, C. The Three Books of the Potters’ Art. Vendin-le-Vieil: Editions la Revue de la céramique et du verre, 2007.
Rosi, F., Manuali, V., Miliani, C., Brunetti, B.G., Sgamellotti, A., Grygar, T. and Hradil, D. 2008. “Raman scattering features of lead pyroantimonate compounds. Partt I: XRD and Raman characterization of Pb2Sb2O7 doped with tin and zinc”, Journal of Raman Spectroscopy 40(1): 107-111.
Wainwright, I., Taylor, J.M. and Harley, R.D. “Lead antimonate yellow”, in R.L. Feller (ed.), Artists’ Pigments. A Handbook of their History and Characteristics, vol. 1. Cambridge: Cambridge University Press, 1986: 219–254.
Zecchin, L. Il Ricettario Darduin. Un Codice Vetrario del Seicento Trascritto e Commentato, Venezia: Stazione Sperimentale del Vetro, 1986.
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]
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.
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.’
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]
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]
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),” https://artechne.wp.hum.uu.nl/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 redazionidel 1550 e 1568, Vol. 2 , 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.
Heat is transformative, brings about change, separates substances or bring them together. Every student of chemistry knows how to enable or enhance a chemical reaction by applying energy to a system, usually in the form of heat. Early modern practitioners did not think otherwise. Fire was the transformative element and key to the production of all kinds of different materials, ranging from the philosopher’s stone to artisanal products such as glass, porcelain or pigments. Applying heat to bring about change is publicly ingrained thermodynamics, but one thing is even more obvious. Once heated, things have to cool down again.
When the request came to write a blogpost on cold and recipes, I was somewhat hesitant. Heat seems to elicit the most interesting stories and anecdotes, but interesting cases with respect to cold failed to come to mind immediately. Hence, I tried a different approach and looked at how cold featured in a collection of overtly practical notes on the preparation of paint materials collected by the Dutch polymath and painter Simon Eikelenberg (1663-1738). Intended for publication, he promised his readers an “accurate descriptions of the origin of making, preparation and general use of paint materials, oils, mix-fluids and varnishes.” It was within the confines of this manuscript that I began to discern two themes with respect to cold in practices of making.
It is only when things have cooled down that the transformative work of heat can really be judged. Eikelenberg describes for instance how he experimented with minium, a red lead-based pigment, which he heated in a crucible and placed in a fire. “The more it glowed, the more the minium turned yellow near the sides of the crucible, the lowest parts alike; which, when it was cold, appeared to be nothing else but yellow massicot.”  Eikelenberg also describes the preparation of various varnishes. Here too, quality and properties of substances are explicitly observed after the varnishes have cooled down. “When the varnish was cold I found that it was rather thin and that it did not cover well.”  Another varnish was prepared on a hot sand bath, after which Eikelenberg “filtered it through a cloth and let it cool: it appeared then as a thickish and yellowish varnish.”  Pay attention to the word “then”: there is a clear order of things that speaks through Eikelenberg’s notes. Being cold is a condition that precedes testing and Eikelenberg makes that rather explicit.
Whereas heat is transformative, it is only in the absence of heat that things can be trusted to stay the same. Continuing with the varnishes, Eikelenberg was well aware that their preparation does not stop after the ingredients have been heated and combined. As long as it is still hot, the apparently homogeneous concoction can easily coagulate and fall apart. Eikelenberg wrote in his notes: “We can conclude that to prevent curdling it is necessary not to stop stirring before the mixture is cold.”  Indeed, each time he made varnishes, Eikelenberg made sure to keep stirring until everything was cooled down: “stirring steadily until all was cold” or “having stirred until it became cold”.
For Eikelenberg, heat was both friend and foe and until his varnishes reached firm, cool ground, they required careful guidance and attention. Cooling down was thus as arduous a process as heating the mixture was in the first place. Yet, once cooled down, true colors are revealed – deprived from heat and stabilized by the cold.
 Simon Eikelenberg, “Aantekeningen betreffende schilderen,” MS 391, Collectie Aanwinsten, Regionaal Archief Alkmaar: fol. 1. “Naukeurige beschrijving van de oorsprong of making, bereiding en ’t algemeen gebruik der verfstoffen, olijen, mengvogten en vernissen.”  Simon Eikelenberg, “Aantekeningen betreffende schilderen,” MS 390, Collectie Aanwinsten, Regionaal Archief Alkmaar, fol. 806. Original: “na mate dat het gloejend wierd, veranderde de menij die naast tegen de zijden van de kroes aan-zat en wierd geel, gelyk ook ’t onderdtste; ‘t welk doe ‘t kout was niet anders dan gele masticot geleek”.  Eikelenberg, “Aantekeningen betreffende schilderen,” MS 390, fol. 827. Original: “Doe de vernis koud was bevond ik ze wat dun en datze niet genoeg dekte.” Translation from: A. van Schendel, “Simon Eikelenberg’s Experiments on the Preparation of Varnishes,” Studies in Conservation 3 (1958), 130.  Eikelenberg, “Aantekeningen betreffende schilderen,” MS 390, fol. 802. Original: “Doe ‘t wel vermengt was, kleijnsde ik ‘t door een doek en liet het kout worden, wanneer ‘tzelve een dikagtige en geelagtige vernis vertoonde” Translation from: Schendel, “Simon Eikelenberg’s Experiments,” 128.  Eikelenberg, “Aantekeningen betreffende schilderen,” MS 390, fol. 824. Original: “Hieruijt kan men afnemen dat om ’t schiften voor te komen, men niet moet op-houden met roeren voordat se kout is.” Translation from: Schendel, “Simon Eikelenberg’s Experiments,” 129.  Eikelenberg, “Aantekeningen betreffende schilderen,” MS 390, fol. 827. Original: “gestadig omroerende totdat het gantschelijk koud was.” Translation from: Schendel, “Simon Eikelenberg’s Experiments,” 130. Eikelenberg, “Aantekeningen betreffende schilderen,” MS 390, fol. 832. Original: “tot koutwordens toe geroert te hebben”.
Slipped within Anna Maria Luisa’s recipe collection is a small bound pamphlet that instructs the user how to tint or dye white marble various colors. In just sixteen pages, the unknown author details the ingredients, processes, and necessary apparatuses needed to create three different reds, two blues, three yellows, three greens, and even fake the signature black or grey veining of “pavonazzo” marble. While the secret to tinting natural looking marble was certainly valuable artisanal knowledge, it is the last three pages of the booklet that are particularly interesting. Without explanation, the pamphlet suddenly shifts topics and details “a particular secret for a styptic water that quickly stops bleeding wounds and torn guts.” The descriptive title continues by suggesting that you can “try it on a rooster by piercing its head with a sharp needle, and the rooster will heal in fifteen minutes.”
The first step of the recipe instructs to dissolve a quarter of an ounce of rock alum in one ounce of “acqua rosa” (rose water), which was then added to a quart of “allume bruciato,” or calcined aluminum sulfate. This mixture was then placed in a “digestione,” which was an alchemical apparatus for distillation that dissolved a body in water or alcohol over mild heat. The recipe calls for the mixture to be heated for an hour and until clear. The second step in the recipe is to dissolve a quarter of an ounce of lead acetate in an ounce of distilled vinegar with one forth of pulverized candied sugar. For the third step, a fourth of pulverized copper sulfate from Cyprus is added to an ounce of “acqua di piantagine.” The fourth step calls for calcined red, or Roman vitriol (sulphuric acid) to be boiled with two ounces of urine from a healthy creature. The fifth and final step is to combine an ounce of strong lime into an eight of sublimated and pulverized mercury, which is “digested” to a clear heat for an hour. Once these five steps are completed, everything is to be mixed together in a flask for sublimation and to “digest” for twelve hours.
When I first came across this recipe I was unsure what to make of it, and its inclusion in a pamphlet dedicated to the act of tinting marble perplexed me. But as it turned out, this funny little pamphlet held the key to better understanding Anna Maria Luisa’s recipe collection as a whole. Recipes collected by women are traditionally viewed as domestic manuals used to safeguard the health of the home and treat commonplace illnesses. In general, and as previously discussed here on the Recipes Project, recipes were “repositories for useful knowledge” and share a desired goal to unlock nature’s secrets. In the case of Anna Maria Luisa, however, useful knowledge extended beyond the preparation of simples and household medicines. Her recipe collection reveals an interest in collecting and amassing experiential alchemical knowledge. The creation of styptic water used the same ingredients, apparatuses, and alchemical processes detailed and drawn in the recipes for marble dyes that preceded it.
In addition to highlighting one Princess’s interest in alchemy, this pamphlet also speaks to two important issues when studying early modern recipes from a modern perspective. First, science, medicine, and technology at the late Medici court existed in a world in which our modern categories of knowledge simply did not apply. In eighteenth century Florence, artisanal practices, science (or natural history), and medicine were closely connected thanks to alchemy. For the late Medici court, alchemy was not associated with the mysterious or the occult. Alchemy was an applied science that used experimental activities to investigate and transform nature. These practices produced experimental activities in metallurgy, refining salts, producing dyes and pigments, the manufacturing of man-made gemstones and stones, glass and ceramics, and the creation of chemical medicines. Each of these seemingly disparate pursuits were united by process rather than the specific product produced.
This early modern emphasis on process over product brings me to the second issue concerning the studying early modern recipes. While recipes are certainly important historical objects, they are often closely associated with or celebrated for the product they produce. This emphasis on product over process, however, can belie the true value of many recipes. As is in the case of the styptic water. Was Anna Maria Luisa interested in tinting marble or was she interested in better understanding complex alchemical processes that could transform nature and the human body? Thanks to this pamphlet, I now argue the latter.