Eggs and Invisible Ink: George and Giovanni

By Sean Coughlin

In a 2015 episode of Turn, a US Revolutionary War TV drama on AMC, George Washington’s spy Abraham Woodhull uses a special ink made with alum to write secret messages under the shells of hard-boiled eggs. The technique was also advertised on the show’s Twitter in 2014, a year before the episode aired (Figure 1).

Figure 1: Teaser tweet before the airing of the episode. Image via AMC Twitter.

Turn is based on a 2006 book by Alexander Rose called Washington’s Spies: The Story of America’s First Spy Ring, but there is no mention in the book of any such technique. Instead, it seems to come from a 2009 book by John A. Nagy, Invisible Ink: Spycraft of the American Revolution. That book describes an ink that is able to permeate the shell of a hard-boiled egg, leaving the message hidden inside and no trace of writing on the shell. It is not attributed to George Washington and his spies, however, but to Giambattista della Porta. Nagy writes:

“In the fifteenth century Italian scientist Giovanni Porta described how to conceal a message in a hard-boiled egg. An ink is made with an ounce of alum and a pint of vinegar. This special penetrating ink is then used to write on the hard-boiled egg shell. The solution penetrates the shell leaving no visible trace and is deposited on the surfaced of the hardened egg. When the shell is removed, the message can be read.” (John A. Nagy, Invisible Ink: Spycraft of the American Revolution, 2009: 7)

Nagy’s account of della Porta’s recipe seems in turn to have come from 1999 book by Simon Singh called The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography. Singh, however, leaves it unclear whether the egg is to be hard-boiled or raw when one writes on it:

“In the fifteenth century, the Italian scientist Giovanni Porta described how to conceal a message within a hard-boiled egg by making an ink from a mixture of one ounce of alum and a pint of vinegar, and then using it to write on the shell. The solution penetrates the porous shell, and leaves a message on the surface of the hardened egg albumen, which can be read only when the shell is removed.” (Simon Singh, The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography, 1999: 10)

Singh’s description of della Porta’s recipe only appears in the first edition of The Code Book. In later editions it is missing without comment. The reason might be found by reading della Porta himself, who in Book 16 chapter 4 of his Natural Magic mentions the technique, but neither claims to have invented it nor to have gotten it to work:

“Africanus teaches thus: ‘grind [oak] galls and alum with vinegar, until they have the viscosity of ink. With it, inscribe whatever you want on the egg and once the writing has been dried by the sun, place the egg in sharp brine, and having dried it, cook it, peel, and you will find the inscription.’ I put it in vinegar and nothing happened, unless by ‘brine’, he meant sharp lye, what’s normally called capitellum” (della Porta, Magia Naturalis 16.4: Latin 1590, English 1658)

Della Porta attributes the recipe to Africanus, probably Sextus Julius Africanus, a 2nd–3rd century CE traveler, writer and chronicler, whose recipe for an egg-permeating ink is preserved in the 10th century Greek compilation known as the Geoponica, of which della Porta’s recipe is a literal Latin translation. Unlike Singh’s or Nagy’s recipe, della Porta’s includes oak gall (an ingredient often found in inks as a pigment) and lacks precise measurements.

The measurements and techniques described by Singh seem similar to a recipe printed on page 143 of the 1973 New Earth Catalogue (Figures 2 and 3):

Figure 2: The New Earth Catalogue: Living Here and Now, ed. Scott French and Gnu Publishing, New York: Putnam Berkley Press, 1973. Image via MareMagnum.

Writing Under Shell of an Egg. Dissolve one ounce of alum in a half pint of vinegar and use a small brush to paint whatever you wish to appear on the shell of an egg. After he egg has dried completely, boil it for 15 minutes [...].
Figure 3: P. 143 (detail, via Google Books Snippet View) of The New Earth Catalog: Living Here and Now.
This recipe uses half the amount of vinegar. It also mentions that a small brush is to be used and says to boil the egg for 15 minutes. None of these details are in Singh’s or in della Porta’s version.

This recipe shares a strong family resemblance to a one published by the USDA in 1965, whose purpose was to get children to eat more eggs. We know this because the USDA’s suggestion was picked up by the New York Times and published on page 14 of the 29 May 1965 issue (Figure 4):

Mess on an Egg is Tempting to Child. To increase a child's consumption of eggs, us "invisible writing," the United States Department of Agriculture suggests. Secret messages can be painted on the outer shell of eggs before they are hard-cooked, and nothing will be visible until the egg is cooked and the shell removed. The message will be on the hard-cooked egg white. To make the "magic ink," dissolve one ounce of alum (available in drugstores) in one cup of vinegar. Use a small pointed brush to write on the shell. Let it dry thoroughly and then cook the eggs in simmering water for about 15 minutes. Cool quickly.
Figure 4: P. 14 (detail) of 29 May 1965 New York Times with an invisible ink recipe attributed to the USDA.

Sometime between 10 and 20 years earlier, either in 1946 or 1959, a similar version similarly targeted to children was published in volume 14 of Richards Topical Encyclopedia, an encyclopedia ordered by theme that was sold door to door in the US (Figure 5).

The Warning Beneath the Egg Shell. Mix an ounce of alum with a half pint of vinegar. Then with a fine brush, using the mixture as an ink, write a message--a joke, a prophecy, anything you like--on the shell of an egg. After the egg is boiled in water for about fifteen minutes, the writing will disappear, but your unsuspecting friend who removes the shell will find the message on the hard-boiled egg inside.
Figure 5: P. 136 (detail) of volume 14 of Richards Topical Encyclopedia, published either in 1946 or 1959.

Another 10 (or 20) years before that, we find the recipe on page 58 and 132 of the February 1936 issue of American Druggist. A reader from Oregon asks for the recipe of a solution used to mark eggs. The editor replies that the “trick” is described ‘in Henley’s “Book of Recipes”.’ (Figure 6)

Egg Shell Marking. "Oregon" used to mark eggs with a mixture of brown sugar syrup and some acid. He has forgotten the formula. The trick, as described in Henley's "Book of Recipes" is as follows: (Continued on page 132) Notes and Queries...continued from page 58. Dissolve an ounce of alum in 8 ounces of vinegar and use the solution to "write" upon the egg, using a small pointed camel's hair brush. Dry the egg and boil it for about 15 minutes. By that time the markings on the shell will have disappeared but when the shell is removed the writing will appear on the hardboiled white of the egg.
Figure 6: P. 58 and 132 (detail) of February 1936 issue of American Druggist.

The editor’s recipe is not obviously the one “Oregon” was after (it includes neither sugar nor acid) but the details are familiar: 1 oz alum, 8 oz (= 1 cup = 1/2 pint) vinegar, a small, pointed brush, 15 minutes boiling. Some details are new: we’re told the brush should be camel’s hair (I will come back to this in the sequel).

The editor of American Druggist also gives a source: Henley’s “Book of Recipes”. The Norman W. Henley Publishing company was active in the United States in the early 20th century and beginning in 1907 published almost yearly editions of an extremely popular book of household recipes: Henley’s Twentieth Century Book of Recipes, Formulas and Processes: Containing Nearly Ten Thousand Selected Scientific, Chemical, Technical and Household Recipes, Formulas and Processes for Use in the Laboratory, the Office, the Workshop and in the Home By Gardner D. Hiscox.

I checked the 1907 edition of Henley’s, but found nothing. I continued looking for references to the recipe closer in time to the American Druggist issue to refine the search. I found two earlier instances: page 97 of the January 1930 issue of Popular Science, and (slightly earlier) page 110 of the September 1929 issue of Field and Stream, where it is referred to as ‘an old hex trick’ (Figures 7 and 8):

Making Writing Appear on Whites of Boiled Eggs. An easy and effective trick is to letter a prophecy on the shell of an egg, using a mixture of an ounce of alum in a half pint of vinegar as the medium and applying it with a fine brush. Place the egg in water and boil for about fifteen minutes. The lettering on the shell will disappear, but on removing the shell, the prophecy will be seen on the hard-boiled white of the egg.
Figure 7: P. 97 (detail) of January 1930 issue of Popular Science.
1001 Outdoor Questions. By Iroquois Dahl. Ques. Not long ago I saw the egg of a domestic hen boiled, and when cracked and opened, the following words and figures appeared, perfectly printed on the white of the egg: “Ware will come in 1932.” As I am a disbeliever in hokum and bunk, I would appreciate information on how this was done? Ans. This sounds like an old hex trick. You can write on the inside of an egg by dissolving 1 ounce of alum in ½ pint of vinegar. With a small pointed brush, outline whatever you writing you desire on the shell of the egg with this solution. After the writing has dried thoroughly, boil the egg for 15 minutes. All trace of writing should disappear from the shell, and when the egg is cracked and shelled, the writing will appear on the hard-boiled white.
Figure 8: 1985 reprint of p. 110 of September 1929 issue of Field and Stream.

If Henley’s was the ultimate source, the recipe had to have appeared sometime before 1929. I checked the 1925 edition, but it was nowhere to be found. The next edition was published in 1929, the same years as the Field and Stream recipe. There it was on page 786 (Figures 9 and 10):

Wood Polishes; Wood Renovators; Wood, Securing Metals To; Wood, Waterproofing; Wood’s Metal; Wool Fat; Worm Powder for Stock; Writing, Restoring Faded […].
Figure 9: P. 786 (detail) of Henley’s, the 1925 edition. No recipe.
Wood Polishes; Writing Under the Shell of An Egg: Dissolve one ounce of alum in a half pint of vinegar with a small pointed brush outline whatever writing you desire on the shell of the egg with the above solution. After the solution has dried thoroughly on the egg, boil it for about 15 minutes. If these directions are carried out all tracings of the writing will have disappeared from the outside of the shell--but when the shell is cracked open the writing will plainly show on the white of the egg.
Figure 10: P. 786 (detail) of Henley’s, the 1929 edition, with the earliest version the author could find of this recipe.

The recipe contains many of the characteristics of the one that has been passed down in American lore and attributed in one form or another to George Washington’s spies or Giambattista della Porta: 1 oz. alum, ½ pint vinegar, a small brush, 15 minutes of boiling.

Given the reach of Henley’s “Book of Recipes” in the US, this is not surprising. But Henley’s recipe also lacks a key ingredient from the recipe that della Porta attributed to Africanus: oak gall. How and when this ingredient dropped out from a recipe reliably passed down for over a thousand years is another story.

This post continues a study of how a 3rd century recipe for a magic ink, despite the fact that it probably never worked, still managed to work its way into American popular culture in the 20th and 21st centuries. An earlier part of the study is posted here.


Cherries Galore in a Cesspit

By Merit Hondelink

As an archaeobotanist, an archaeologist specialised in studying plant remains found in archaeological excavations, I aim to reconstruct and interpret the relationships between humans and plants in the past. Archaeological plant remains, also known as subfossil plant remains, help us to reconstruct the former landscape and inform us how humans exploited it and even transformed the vegetation. Archaeobotanists do not necessarily study one time period, nor a specific region or topic. They can study plant remains from the Palaeolithic or the 20th century, and everything in between. They can focus on one specific site, work across the country or continent, and even work worldwide. They can delve into topics such as natural vegetation, forestation, domestication, trade, food consumption and much more. The one thing that all of this has in common is the link between humans and plants. But most archaeobotanists do specialize, most notably in the plant parts they study, such as fruits, seeds, pollen, wood or phytoliths. And most archaeobotanists have a beloved time period, favourite region or topic that they find most intriguing. In my case my research focuses on early modern Dutch urban food consumption.

I study what people ate in early modern Dutch cities, and how this changed through time. The best way to study what people ate in the past, is to look at their excrement and kitchen refuse, both of which can be found in the archaeologists treasure trove: the cesspit. These latrines were used to empty one’s bowels, but also served as a place to discard kitchen refuse and household waste. The content of a cesspit consists of organic remains from plants and animals, inorganic (culinary) material culture such as earthenware, glassware and ceramics, but also wooden cups and plates, as well as (decorative) objects, personal belongings and much, much more.

Figure 1: A selection of faunal and floral items found in a late medieval cesspit sample from Groningen. Photo: Dirk Fennema.

The content of an archaeobotanical cesspit sample consists of, among others, floral remains in different shapes and sizes (Figure 1). The items are sorted with the use of a microscope (Figure 2) and identified on a species level (and sometimes even on the level of species variety) by using a reference collection (Figure 3). The Groningen Institute of Archaeology offers a wonderful digital, open access, reference collection, see

Figure 2: A peek through the microscope. Visible is a fragment of text and different seeds and fruits, taken from an early modern Delft cesspit sample. Photo: Merit Hondelink.

When the content of a cesspit sample is analysed, sorted and identified, the interpretation begins. What can these plant remains tell us about past human-plant relationships? Most plant species are interpreted in a standardized way: wild plants inform us about the vegetation composition, make-up of soils and hydrology, whilst agricultural weeds in particular inform us about the crops grown and their local, regional, international or even global provenance. Wild but poisonous or toxic plants inform us about potential medicinal applications. A majority of plant species found in cesspits are classified as economic plants, grown as a food crop or cultivated for other useful purposes, such as fibres for textiles or seeds for oil. Identifying edible plants helps us better understand what plants people used for food and which parts people consumed. It also helps us better understand how food was prepared in the past, as preparation marks can be left behind on seeds and fruits.

Some preparation marks are easier to identify than others: nuts need to be cracked to get to the seed; apple seeds may be sliced when cutting up an apple, cereals can be ground, resulting into fragmented bran. But sometimes the archaeobotanist finds fragmented plant parts that, at a first glance, do not make sense.

Figure 3: A small selection of the tubes from the archaeobotany reference collection housed at the Groningen Institute of Archaeology (GIA) at the University of Groningen. Photo via GIA.

I have come across dozens and sometimes hundreds (or even more) cherry stones and plum stones in a single cesspit sample. No surprise there, cherries and plums were grown in local orchards, sold in the market and consumed with gusto. Most of these stones will have been discarded in the cesspit as a result from eating the fruits and spitting out the stones, or after de-pitting the fruits for dinner preparation. Only a small percentage is assumed to have been accidentally swallowed and secreted as excrement. Still, archaeobotanists find many fragments of cherry and plum stones (Figure 4). This is something that raises questions when you think about it. Why would these sturdy fruit stones be fragmented? A more pressing question when you are aware that the Rosaceae family, among others also including almond, peach, and even apple, contains – to varying degrees – hydrocyanic acid, also known as hydrogen cyanide and sometimes called prussic acid. The seed coat and fruit wall protects the consumer from digesting this acid, which can be poisonous when consumed. So why would someone break the stones of these fruits?

Figure 4: Two fragments of cherry stones found in an early modern cesspit in Vlissingen. Photo: Merit Hondelink.

To test the assumption that cherry stones were fragmented intentionally, and not through, for instance, pressure, an experiment was devised. Cherries were bought at the farmer’s market and taken to a physics lab to measure the pressure required to fragment the stones. After a number of tests, the calculated force to fragment a cherry stone averaged 23,9 kg or 239 Newton (Graph 1). This makes it more plausible that the stones were intentionally fragmented, as opposed to – for instance – fragmentation due to soil pressure.

Graph 1: Force needed to fragment a cherry stone. On the vertical axis the force (N), on the horizontal axis the elongation (μm). The point where the line falls is the moment the cherry stone breaks (max. force – max. elongation).

Consulting early modern cookbooks provided me with a list of recipes requiring the cook to de-stone cherries for the preparation of jams, sauces, syrups and tarts. Delicious experiments ensued, but I did not manage to fragment cherry stones whilst cutting and de-stoning, pressing through a cloth or colander, or by just baking the fruit with stones in a tart in the oven. Working a batch of cherries with a mortar and pestle did the job, though. But than you would have to pick the fragmented stones from the mushy cherries: not ideal at all. Picking up the eighteenth century encyclopaedia compiled by Noël Chomel gave me the hint I needed. In the Dutch version of his Dictionnaire œconomique (Algemeen huishoudelijk-, natuur-, zedekundig- en konst- woordenboek), he mentions different recipes for preparing cherries. Two recipes for cherry liquor instruct the reader to fragment the cherry stones by using a mortar and pestle (Figure 5). The fragmented fruits, including the stones and (I assume) the seeds are added to the brandy (Dutch: brandewijn) and, after closing the bottle, the mixture is put in the sun to infuse. Adding spices such as cinnamon, cloves and sugar is optional, according to the author.

Figure 5: How to make a pleasant cherry liquor (Noël Chomel, 1778).

So, it is plausible that the fragmented cherry stones found in early modern cesspits are the result of the domestic production of cherry liquor. Other fruits, such as plums and peaches, are also used to make a fruity liquor according to Chomel’s encyclopedia. However, what happens to the acid contained in the seeds? That requires further research. It might be that the prescribed infusing in the sunlight helps denature the acid into harmless molecules, leaving only the (bitter) taste behind. This line of research will be undertaken come summer with the aid of a brewer and some chemical analysis. In the meantime, a cherry and cinnamon flavoured lemonade is my poison of choice. Bottoms up!

Learning from a “Living Source” in Working with Historical Recipes: Reflections on the Burgundian Black Collaboratory

By Jessie Wei-Hsuan Chen

This week, we continue our series of cross-postings on a fascinating hands-on, collaborative research project into recipes for Burgundian Black, organized by Dr. Jenny Boulboullé. In today’s selection, we hear from Jessie Chen on her experiences of the project. This post is our second entry in the series, reproduced from Artechne, July 3rd, 2019. (Joshua Schlachet)

Burgundian Black Collaboratory

Between the 16th and 18th of January, I was invited to participate in the Burgundian Black Collaboratory.[1] For this workshop, experts from different fields joined forces to experiment with reconstructions of early modern black dyeing technologies based on a selection of historical recipes (Fig. 1).[2] The workshop is part of the research for a collaborative exhibition project that will be on view at Museum Hof van Busleyden in Mechelen later this year, and an edited-volume-in-planning on the subject of “Burgundian Black.” For now, I want to write about some thoughts on the method of learning from a “living source” using my own experience of the workshop.

Fig. 1. Experts from different fields experimenting with different recipes in our temporary lab, which was a greenhouse on the farm De Kreake in Húns in Friesland.

What is a “living source”?

In her article, Timea Tallian proposed three groups of living sources that can help fill the gaps in understanding historical recipes: experts, masters, and practitioners.[3] The definition of the three groups is more suggestive than hard-drawn. In general, “expert” refers to a person who conducts practical and/or scientific experimentation or reconstruction based on historical documentation. “Master” refers to a person who has acquired an art or craft through apprenticeship and continued to practice it for a long time. “Practitioner” refers to a person who has gained most knowledge from personal experience in making art/craft and self-motivated research into historical techniques.[4]

A simplified experience of working as an apprentice

During the Burgundian Black Collaboratory, I was in the same group as Jo Kirby-Atkinson, former Senior Scientific Officer at the National Gallery in London and co-author of the seminal book Natural Colorants for Dyeing and Lake Pigments.[5] Jo is, in every aspect of the term, an expert on natural colorants and materials, whereas I am a novice with no prior experience in working with natural dye and textile. While not strictly, the dynamic of my group resembles a historical workshop, with an expert/master showing the ropes to an apprentice. Our group was given three seventeenth-century recipes to decode, with two originally written in Dutch, but translated into English, and one in French.[6] All three recipes yielded rich black dyes (Fig. 2), even though we had to compress the multiple-day dyeing-processes into only a few hours.

Fig. 2. Top left: our equipment for the experiments; Top right: the different textiles we gathered before dyeing them black; Bottom left: in the middle of dyeing following the instructions of one of the Dutch recipes; Bottom right: final results of our experiments.

For three days, I followed Jo around, gathered and prepared the needed materials as she had instructed, and attentively listened to her explaining the reasons behind the decisions she made to follow or modify the recipes when dyeing our textile. Unlike many historians that start working with recipes by reading and interpreting the texts right away, I started by listening to and absorbing the knowledge of the expert/master.

In fact, this has always been how I learned historical techniques, or any artistic techniques. When I was in art school, manuals and how-to guides were always part of the assigned readings for classes, but I seldom consulted them. Instead, I observed what the professors did during demonstrations and tried to replicate the processes and results. For my first lesson in historical remaking, I learned an eighteenth-century metal-casting technique (Fig. 3) through the step-by-step explanations from an Amsterdam-based silversmith and conservator.[7] Similarly, I gained my knowledge in early modern printing (Fig. 4) by working alongside a master printer who learned the trade in a workshop. While historical recipes and instructions still play an important part in my research of these techniques, I do not usually read them until after I have some hands-on experiences.

Fig. 3. Left: removing the lion head ornament from the casting flask; Right: the cast and the original lion head ornament.


 Fig. 4. Two process photos of printing with a hand press.

Limitation or liberation?

How does learning from these experts affect my reading of historical recipes then? Does knowing the practical aspects of a technique help me understand the recipes better? Or does it prevent me from finding other possible interpretations of a recipe because I am conditioned by what the experts have shown me?

Upon reflection of the workshop, I noticed that my take on the original source is, indeed, shaped by Jo. When going through the recipes afterwards, my mind replayed the steps we took to dye our textile black. Interestingly, the recipes became so straight forward. In the imagined laboratory, my mind automatically filled in the gaps in the recipes with the decisions and measurements Jo made during the workshop. She has taken all the guess work out of interpreting the recipes, and what I have is a very cleaned-up, and perhaps all-too-easy, version of the processes.

However, I also noticed that I started to question some other things that are not necessarily directly related to the texts in the recipes we were testing, but to the broader historical contexts. For example, for one of the recipes we put linen and woolen materials in the same dye bath for the experiment. The linen came out more of a gray than black. Jo explained that in order for linen to get to the same level of blackness as wool, it would require a much longer time to mordant the fabric with alum. Historically and practically speaking, linen would not have been dyed with this particular recipe anyway because the cost of the overdyeing process (dyeing with multiple dye baths) would have been too expensive for the fabric. Such a recipe, thus, would have only been used for high quality material like wools and silks. These comments got me curious about the alum trade and the regulations of dyeing certain fabrics in the early modern period to which I have never paid attention before.

From novice to expert, eventually…

To answer my own questions, I think that gaining the hands-on skills from an expert/master is beneficial to prevent me from getting caught up with words and sentences as a novice; instead, I can focus on connecting the technique of investigation to its larger historical and social context. Learning from these experts also makes me become more aware of the oral knowledge transfer in a workshop in addition to written recipes. As I am only at the beginning of working with historical recipes, there will be more opportunities to interpret and experiment with recipes for different materials and techniques without the aid of an expert. Much like an apprentice who would become a master, I think that I will eventually find my own perspective on working with recipes.


[1] The workshop was organized by Jenny Boulboullé (ERC Artechne Project, Utrecht University & University of Amsterdam) and Claudy Jongstra (textile artist), and prepared in collaboration with Natalie Ortega Saez (University of Antwerp) and Art Proaño Gaibor (Cultural Heritage Agency of the Netherlands). It was hosted by Claudy and her team in Húns in Friesland, The Netherlands, and received funding from the Museum Hof van Busleyden, the ERC Artechne Project, and Studio Claudy Jongstra.

[2] For more academic blogging on historical recipes and how historians have been studying them, see The Recipes Project,

[3] Timea Tallian, “Living sources: experts, masters, and practitioners,” in The Artist’s Process: Technology and Interpretation: Proceedings of the Fourth Symposium of the Art Technological Source Research Working Group, eds. Sigrid Eyb-Green, Joyce H. Townsend, Mark Clarke, Jilleen Nadolny, and Stefanos Kroustallis (London: Archetype Publications, 2012), 10.

[4] Ibid.

[5] Jo Kirby-Atkinson, Martin van Bommel, and André Verhecken, eds., Natural Colorants for Dyeing and Lake Pigments: Practical Recipes and Their Historical Sources (London: Archetype Publications, 2014).

Jenny was also part of our group; but due to her role as the organizer, she was much needed by other participants and thus I mostly worked with Jo on the hands-on aspect of the experiments during the workshop.

[6] The two Dutch recipes, translated by Hofenk de Graaff, are from the so called Haarlem Manuscript (Recepten-boek om allerlei kleuren te verwen […], Frans Hals Museum, fol. 313-l-l and 95/r/3l) from the second half of the seventeenth century (after 1669). The unpublished French recipe, transcribed by Jenny, is from the first half of the seventeenth century. She found it in the Archives of the Royal Society in London (Classified Papers III(1)).

[7] This technique is one of the investigations for the PhD project of Thijs Hagendijk. To learn more, see Thijs Hagendijk, “Learning a Craft from Books: Historical Re-enactment of Functional Reading in Gold- and Silversmithing,” Nuncius 33 (2018): 198–235. Alternatively, Thijs has also written a few blog posts on the subject, see, for example, “How to Read Early Modern Instructions for Gold- and Silversmiths,”

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).

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