Colouring metals in the Far East

By Agnese Benzonelli

How far can someone go in the name of research? In my case quite a long way. For a month, I loosely taped tiny plates of metal to my hands and woke up every morning with green stains on them. I was investigating craft recipes employed in the far East since the fourteenth Century to create coloured metal and alloys used for beautiful small artefacts. Whereas Western taste preferred the natural colour and the polished lustre of metals, the Eastern preference was to use the process of chemical patination, where different chemicals react with the surface of copper and copper alloys to form new coloured compounds.

Fig.1: Left: a tsuba (handguard of Japanese sword) made of shakudo and gold; BM-TS244. Right: a Chinese gu-tong box; BM-1992,1109.2. Photos made by A. Benzonelli.

The Japanese created a whole class of coloured alloys, called irogane. They added small amounts of different elements to the copper and simmered it in a solution containing copper salts, alum, vinegar and other ingredients, to form coloured patinas on the surface. The most beautiful patina, shakudo, was made with copper and gold and achieved a deep blue-black colour. Combining a variety of alloy compositions and solution ingredients, they were able to create hues ranging from pale brown to black. Inlaying different irogane, gold, silver, and lacquers, they were able to create small artefacts and swords fittings with complex and visually impressive designs and patterns.

Fig.2: Picture of the 13 Japanese solutions created and tested taken from Japanese recipes reported in Eastern books.

Later on, Chinese craftspeople imported the technique from Japan, possibly through travellers or trying to copy the Japanese artefacts, and, from the Ming period (1368-1644), they used it to colour ink or tobacco boxes. In contrast to the Japanese irogane, the Chinese would patinate a gold-silver alloy only, which resulted in a dark colour similar to that of shakudo, which they called gu-tong. In both cases, the precious metal content was 1-3%, a larger amount would not affect the final patina colour.

There’s not a lot known about the two different recipes the Chinese craftsmen employed to produce their patinas. However, we do know that one process they utilised was similar to that used by the Japanese to produce the irogane,butwe have no precise recipes for the solutions. Another involved handling the metal until the perspiration from their hands corroded the surface.

Creating and play with metal colours has always fascinated me. Why using gold and silver to achieve that dark colour, instead of cheaper alternatives? What was the role of the different ingredients used in the recipes? Could sweat really be used as a patinating solution? Why did Japanese recipes tell not add precious metals to bronze (copper alloyed with tin) but only to pure copper? Could it be confirmed through scientific analysis that the technology was really transmitted from the Japanese to the Chinese culture? To find answers, I needed to conduct a systematic experimental research which could explain the reasons behind the technological choices of Japanese and Chinese craftsmen.

 I reproduced a series of alloys with tin, gold and silver, which I then patinated, following the recipes for shakudo and gu-tong from available texts. These are not numerous, as the recipes were mainly kept as secret and passed from father to son. We have city records, information sheets given by dealers and, in Japan, technical texts on metal working. I analysed the resulting patinas with techniques borrowed from modern material science, and used the experimental data as reference for the interpretation of historical patinated artefacts in museum collections.

I found that, for both the Japanese and Chinese recipes, the presence of gold in the alloy did, in fact, change the colour of the final patinas, which resulted in a better, more uniform and darker hue. I also noted how parameters such as the fine grade of surface polishing prior to the patination, the use of tin-free alloys, the selection of copper acetate as a main ingredient and the addition of vinegar are all processes and actions that led to a reduced patina growth. And as it turned out, sweat was indeed an effective patinating solution in the Chinese patination (as it can be noticed by the green corrosion products left on the hands), but the presence of gold in the alloy composition is nonetheless essential to obtain a dark hue, not achieved in gold-free alloys. Sweat is a slightly acidic solution, similar to that of used by Japanese craftsmen, essential to create a coloured copper oxide on the surface in just 48 hours of handling. Similarly, in both technologies cleaning of the alloy before or after the procedure suggested in Japanese texts and the abrasive action of the hands in the Chinese method are both similar and crucial steps in the patination process. I concluded from these findings that a dark patina was not the only feature that the craftsmen of both cultures had been striving for. They also seemed to be after a shiny appearance, given by the metallic lustre coming from the alloy.

Fig. 3: Alloys of different compositions patinated with Chinese patination.

In combining experimental and historical observations I gained an understanding of the intentions behind the technological choices made by the Japanese and Chinese artisans. My analysis confirmed the deliberate nature of these choices made to achieve dark and shiny blue-black colours otherwise impossible. This confirmed the importance of colour as a driver of these artisanal processes, and supports the idea that the knowledge was transmitted between the two cultures.

Was it worth in the end – the green hands and other discomforts suffered in the name of research? It was the first study to provide a scientific basis to our knowledge of the methods and choices made by those people, the ingredients they employed in making dark patinated artefacts, and contributed to our pool of knowledge of the artisanal methods and practices described in historical sources. So yes, it definitely was, and I would definitively do it again.

Red Thread: A Co-curated Digital Site with Students

By Vera Keller, University of Oregon

Image credit: Gart der Gesundheit, Hortus sanitatis (1485), Special Collections and University Archives, University of Oregon Libraries, Eugene, Oregon. Burgess 109, p. ccxlviii.

The Red Thread site grew out of an interdisciplinary, Honors College seminar, Global History of Color. I made colour the focus of a course for four reasons:

  • it intersects with my own research into early modern experimentation with color;
  • it is a vehicle for teaching a course that is global, interdisciplinary, and material;
  • it is not too intimidating for students;
  • and I thought it would be a way to connect disparate corners of campuses and to build a public intellectual community.

Everyone knows that artisanal production is big in Oregon, but there is little connection between wider public interests in historical craft practices and academic research on those topics. When it comes to the study of material culture, we not only have under-used collections of objects at UO, but also many unique and wonderful resources around campus–an Urban Farm, Craft Center, and Beach Conservation Lab. We also have a highly skilled, curious and passionate local public of artists, crafters, homesteaders and farmers. What we don’t have is a way to connect and strengthen these various constituencies, especially in a way that places the University and historical research at the center of this connection.

Particularly as a faculty member at a public university, I feel that engaging the university with a wider public is part of its mission. Historically, recipe collections have served as forms of social media tracing community building and sharing across different domains of knowledge. At a moment when face-to-face interaction, civil discourse, and communities are weakening on a national scale, we can draw on the strength of this historical genre to engage ourselves, our students, and the public in a collective endeavour to build intellectual community.

Color proved to be an accessible way for both students and the public to engage with primary sources, material practices, and historical artifacts. In the course, we focused on a range of reds: ochre, coral, cinnabar, vermilion, kermes, madder, cochineal, Tyrian purple, brazilwood, logwood, colloidal gold, ruby glass, and red-painted porcelain. Together, we studied the history of these pigments through the lenses of the history of science, the history of medicine, economic history, cultural history and material culture. Each student focused on a single material object from campus collections, which became the subject of their exhibition labels for a co-curated exhibition and a final research paper.

We visited three campus collections: Special Collections and University Archives, the Museum of Natural and Cultural History (MNCH)  and the Jordan Schnitzer Museum of Art (JSMA), with strengths respectively in European, Native American and Asian materials. Through a campus grant for teaching initiatives (the Williams Foundation), I invited a guest speaker to campus for a public event. Marie-France Lemay, the paper conservator at Yale Library, brought with her the Yale Traveling Scriptorium — a traveling showcase of the materials found in premodern books and manuscripts. With Lemay, we explored the Scriptorium alongside rare books and manuscripts from our campus collection. Lemay also demonstrated a cochineal recipe, which highlighted for students the wide range of materials and processes involved in producing premodern books.

Image credit: Sa’di, Gulistan and Bustan, 1600-1699?, Edward Burgess manuscript collection 043, Special Collections and University Archives, University of Oregon Libraries, Eugene, Oregon. MS 43.

The course produced several intertwined outcomes that were oriented simultaneously to the classroom and to the public. The Museum of Natural and Cultural History hosted a small exhibition of the student-researched objects drawn from their collections. A selection of all the students’ work is also featured on a site I was able to build through a grant from our campus Digital Scholarship Center. All the books and manuscripts were completely digitized as part of the grant. My aims in building the site were to advertise our under-utilized campus collections; to highlight my students’ research; and to produce a resource that could be used in other courses and by the public.

With remaining funds from the Williams grant, I built our own version of the Traveling Scriptorium, with help from UO’s conservators Marilyn Mohr and Ashlee Weitlauf. The Scriptorium is a case full of nearly 100 materials. We experimented a lot with packaging and labelling its various parts. Through my use of the Scriptorium in various classroom settings, we tested the ease and rapidity through which it could be unpacked and repacked. When we were satisfied with it, we donated the Traveling Scriptorium to our campus library, where it is now cataloged and can be checked out by faculty for a week at a time. 

The Travelling Scriptorium.

At the same time that I was working on developing the digital Red Thread site and the physical teaching resource, the Traveling Scriptorium, I also worked on an on-going third initiative, “Farm to Book” , a collaboration between myself, the Beach Conservation Lab and the Urban Farm.  We experimented with historical ink recipes drawn from my archival researches with conservators of the Beach Lab. We also planted ingredients for inks and dyes at our Urban Farm.

We’ve held several highly successful public events at the Craft Center and at the new “Dream Lab” in our library where members of the public could craft with our inks produced according to historical recipes, practice calligraphy, hear student presentations on their historical research, explore the Traveling Scriptorium and the Red Thread site, see selections from our rare book materials, and learn about the history of our campus collections. We even served cochineal cake!

Rose and pansy inks at Craft Center Event. UO Libraries, Tayler Bincandi.

My hope is that the Red Thread site can be used in tandem with the Traveling Scriptorium in other classes or in public presentations, either in preparation for a visit to our campus collections, or in the case of large class sizes, in lieu of a group visit. Pairing the hands-on Scriptorium with the digital resource proved to be a great way to minimize some of the limitations of digital surrogates by giving participants a sense of the material constituents of the original books and manuscripts. I used the site and the Scriptorium, for example, during a presentation for a program bringing high school students from underrepresented backgrounds to campus.

The tactile nature of the Traveling Scriptorium offered a great way to draw people in, as members of the public found it fascinating to handle all the little bottles of materials. I purchased one seventeenth-century volume (for less than $100) to include as part of the Scriptorium, so that an actual rare work could travel to events off campus. Being able to hold a four-hundred year-old book always has an immediate effect upon public audiences. The initial wonder and curiosity sparked by these hands-on interactions often then provoked questions and deeper discussions.

Do you think that there is something to gain from connecting classroom instruction on historical practices of making with makers across campus and from your local community? If so, how would you do it?

How to Prevent the Cooling of the Earth: A Page from God’s Cookbook

By Jean-Olivier Richard

Image from Athanasius Kircher’s Mundus Subterraneus (1678 edn.) vol. 1, p. 194.

Historians studying the relationship between climate and recipes (and yes, historians have good reasons to do so; see Jennifer A. Munroe’s post on seasonality and Katherine Allen’s articles on springtime in recipe books and the common cold) usually frame the question in terms of seasonality. In the pre-modern world, ingredients for recipes could often only be obtained in certain seasons or particular climates – the so-called seasonality of recipes. But the concept of recipe, provided one is willing to stretch its bounds, can also help us understand how our ancestors envisioned the role of God and Man in climate change and cosmic history. What if, for instance, one were to think of the Creation account of Genesis as a recipe? The metaphor is not as far-fetched as it may sound. Recipes entail not only ingredients and instructions, but also agency: isn’t God said to have made everything in measure, number, and weight (Wisdom 11:21)? Many early modern philosophers cherished this notion. Let us imagine, with one such philosopher, a page from God’s cookbook:

In the beginning, create the heaven and the earth. Everything should be in a state of chaos. Then, let there be light. Light will bring the world into sight by causing the formless abyss to sort itself out. Over a period of six days, let the sun, the moon, and the planets coalesce like bubbles, as celestial and terrestrial matter separate; on earth, concentric layers of air, water, and dry land will arise around a pulsing core of fire. In the process, bring forth minerals, plants, and animals. This is good, but not good enough. If the primordial light is left unchecked, all mixed and organic bodies will soon break down and dissolve into their elementary constituents; even beings endowed with seeds will stop propagating their kind. To prevent the cosmos from congealing, add Man to the mixture. Let him stir it, and it will be very good.

A caricature of Louis-Bertrand Castel’s “ocular organ” by Charles Germain de Saint Aubin (1721-1786).

The physics treatise that inspires my thought experiment appeared in 1724, when the boundaries between physical, chemical, and spiritual processes were still porous. Its author was the French Jesuit mathematician and natural philosopher Louis-Bertrand Castel (1688-1757), best remembered today for his ocular harpsichord (a musical instrument that played colors) and his quarrels with the likes of Voltaire and Rousseau. To be clear, Castel did not couch his interpretation of Genesis in culinary terms; but he did argue that God’s primordial “light” must refer to the fundamental, mechanical principle of nature, the force causing elementary particles to weigh against one another and to regroup according to their kind — like mercury, water, and oil mixed together end up settling into layers. What Moses called “light,” ancient philosophers like Empedocles, Parmenides, and Epicurus had known confusedly as “love and strife”, “sympathies and antipathies,” “attractions and repulsions.” Since Newton, moderns recognized it as “universal gravitation” — or as Castel would have it, “universal weighing” (pesanteur). Natural philosophy, just like the original chaos, was sorting itself out.

Yet universal weighing could only be half the story. Castel’s main contribution to science, as he saw it, was to demonstrate the need for another principle: a universal lightness, a kind of spiritual leaven or ferment that would counter the weight of nature and sprinkle a little chaos into the world’s regular march toward equilibrium. This principle had to be spiritual, as opposed to mechanical, because a constant mechanical counterweight would cancel out rather than interrupt the course of nature as needed. Now, God could intervene directly to do just that, but that would be beneath His dignity. A popular alternative — giving nature its own spiritual, vital powers — raised the specter of materialism; out of question for a Jesuit. Castel’s solution? God must have delegated the task of disrupting the world to Man, his troublesome steward. Endowed with free will, humans could bring about everything universal pesanteur could not. Local trouble, Castel reckoned, added up to all the meteorological, climatic, and geological changes needed to prevent the world from grinding to a halt and freezing over.

While this might seem to be a recipe for disaster, Castel trusted that God knew what He was doing. The curse of mortality, for one, ensured humans would not slack off, nor overreach their bounds. Since the Fall, Adam and his descendants felt the weight of nature; they had to sweat and toil to delay the hour of their death (death by gravity, that is). On the upside, tilling the land, breeding animals, cutting down trees, draining fens, building canals, mining the earth, manufacturing goods and transporting them for commerce—all this labor, along with the consumption and excretion of food, renewed the mixtures that nature constantly unraveled. Multiplied by the millions, local actions caused ripples: rain, winds, and waves to which Castel attributed weather pattern and climate change. When well concerted, human efforts made the earth compliant; when excessive or deficient, corrective backlashes ensued — storms, earthquakes, volcanic eruptions. On the whole, the world remained hospitable because man-made mixtures, combined with nature’s weighing and sorting action, preserved the planet’s internal circulation mechanism. Carried down by rivers, oceanic currents, and subterranean channels, the by-products of human activity fueled the central fire of the earth, the reservoir of heat for all living beings on the surface. Castel estimated that the sun only contributed a minute portion of heat compared to the earth’s inner furnace, hence the importance of keeping it alive.

Reproduced with kind permission from

Fifty years after Castel published his treatise, Georges-Louis Leclerc, Comte de Buffon (1707-1788) hypothesized that the earth was once a globe of molten rocks, whose age he ingeniously estimated by measuring the cooling rate of molten metal spheres. Revisiting the notion of a “central fire” keeping the planet warm from within, Buffon warned his readers about the inevitable freezing of the world, but also suggested that human industry might counter the process. Framed by debates about climate, gravity, progress, and the place of divine and human agency in nature, the Enlightenment saw scores of new ideas about the history of the earth — some of which presaging in surprising ways today’s anxieties about climate change. Yet Castel his contemporaries also expressed more confidence in human stewardship. Humans were God’s special ingredient in a perfectly well-balanced recipe; their 19th- and 20th-century successors would not be so serene.


Richard, Jean-Olivier. “The Art of Making Rain and Fair Weather: Life and World System of Louis-Bertrand Castel, SJ (1688-1757).” Ph.D. dissertation. Baltimore, Johns Hopkins University, 2016.

Castel, Louis-Bertrand. Traité de Physique sur la pesanteur universelle. Paris: Cailleau, 1724.

Buffon, Georges Louis-Leclerc, Comte de. Les Époques de la nature. Paris: Imprimerie royale, 1780.


Seasonality and the (Re)creation of Early Modern Color Worlds

By Jenny Boulboullé

Color played an important role in the early modern world across a number of areas from arts and crafts to Christian religion to politics to natural history and philosophy. In recent years, scholars have begun to explore how early modern men and women engaged, produced and conceptualized colors within and across color worlds.[1] Just as in early modern culinary and medical recipes, seasonality is a recurrent theme in artisanal recipes. The art of preservation was highly valued for its powers to make flavors and healing properties of foodstuffs, plants and herbs endure well beyond their seasonal availability. In my contribution to the seasonality series I focus on recipes that celebrate the art of color preservation and on the mindful attention to seasons called for in color making recipes. I am particularly interested in the challenges that recipes for making natural dyes and pigments from seasonal products posed to modern historians trying to reconstruct them.

Today the symbolic significance of colors in early modern Europe is perhaps most readily associated with the compellingly colorful medieval and renaissance art works that have survived in sacred spaces and museums.

Figure 1, Caption: Giotto (1266-1337), The Scrovegni Chapel frescoes, Padua, Italy. ca. 1305. Image from Wikimedia Commons.

But in the pre-modern period a deep concern with colors was not limited to the arts: colors were associated with the four humors and close attentiveness to colors was of vital importance to practices of healing in the Hippocritean and Galenic medical tradition.[2] The perception and display of colors was also highly charged with political meanings: colors were a form of symbolic communication and played an important role in consolidating and displaying religious and secular power relations. European courts and courtly events were important sites of “chromatic politics” as contemporary witness accounts and meticulous historical reconstructions of ephemeral, yet splendid and compellingly colorful festive events have shown.[3]

Figure 2, Caption: Peter Paul Rubens, Design for state decorations for the triumphal entry of Cardinal Infante Ferdinand into Antwerp, on April 17, 1635, Hermitage, St. Petersburg. Image from

The historical reconstruction of a sixteenth-century dress, originally created for the Augsburg Imperial Diet from 1530, is a particularly compelling example of the politicized use of brightly colored dress made from dyed textiles.[4] The owner of this dress and his contemporaries might have regarded its colors “as related to intrinsic qualities and powers”. Deep scarlet reds were regarded at that time “as carriers of life and heat, while a strong yellow was linked to gold as metal, which had given its powers by the influence of the sun”. Ulinka Rublack notes the challenges encountered during the reconstruction process. The yellow color obtained in their first dying trials “was just not quite vibrant enough” which was detrimental “as faded hues of yellow could have negative associations of weakness and coldness”.[5]

Other sixteenth century recipes for ‘yellows’ from organic sources, demonstrate that making natural dyes of this color depended on local seasonal knowledge. As Marieke Hendriksen has discussed, here in Utrecht, we are building a new database of artisanal recipes. A quick search in the Artechne Database yields several fifteenth- and sixteenth century German recipes for green and yellow colors that call for buckthorn berries (some with precise indication for picking times, like this one for “Green color” from 1543). Here an Italian one from the anonymous Padua Manuscript (ca. end 16th/17th century), translated and published in English:

To make giallo santo

Take the berries of buckthorn towards the end of the month of August, boil them with pure water, until the water is loaded and thick with color; add a little burnt roche alum and then strain it. You may boil the strained liquor to make the color deeper, mixing with it some very pure gilder’s gesso; then make the color into pellets, and dry them in the shade.[6]

In color recipes such as this one, seasonality and intimate knowledge of seasonal products sensitivities to additives play a key role. Berries had to be picked at specific times of the year to attain the right hues, and while the juice of ripe buckthorn, available in most of Europe, gives a greenish color, also known as sap green, one needs to get hold of unripe berries, fresh or dried, in particular a species imported from the Middle East, also known as “Persian berries”, to attain the deep golden yellow hue that the reconstruction team had envisioned for this dazzling sixteenth-century dress.[7] Only by patiently repeating the dye processes using the right berries picked at the right moment, can the desired vibrant hue of rich quality be achieved – both in the early modern period and during 21th century reconstruction.[8]

Thus, the commission of brightly dyed dresses for display at important events must have been a time-consuming affair that required planning long ahead of the political event and entailed a collaborative process of sourcing and experimenting that depended not only on seasonal knowledge and availability, but was also prone to risks of seasonal change. As Rublack’s work shows, reconstruction research makes us of acutely aware of the complexities and risks posed to those who aspired a part in the “chromatic politics” of the Holy Roman Empire in the sixteenth century. Moreover, as I will show in my next post, color recipe reconstructions allow us to experience the efforts and knowledge that went into the creation of early modern color worlds, which have become unfamiliar to our modern period eye.


[1] Tarwin Baker, Sven Dupré, Sachiko Kusukawa, and Karin Leonhard, eds., Early Modern Color Worlds (Brill, 2016).

[2] Baker, Dupré, Kusukawa, and Leonhard 2016, 4.

[3] Ulinka Rublack, “Renaissance Dress, Cultures of Making, and the Period Eye.” West 86th: A Journal of Decorative Arts, Design History, and Material Culture 23, no. 1 (March 1, 2016): 6–34. doi:10.1086/688198.

[4] Rublack 2016.

[5] Rublack 2016, 23, 24.

[6] Maria Philadelphia Merrifield, Original Treatises, Dating from the XIIth to XVIIIth Centuries, on the Arts of Painting, in Oil, Miniature, Mosaic, and on Glass; Of Gilding, Dying, and the Preparation of Colours and Artificial Gems (John Murray 1849), 708.

[7] Jo Kirby, Susie Nash, and Joanna Cannon, eds. Trade in Artists’ Materials: Markets and Commerce in Europe to 1700 (Archetype Publications, 2010) Glossary, 447.

[8] Rublack 2016, 25.