Happy New Year

January 2nd, 2016 § Comments Off on Happy New Year § permalink

Naples 1476 Watermark

Ship Watermark – Naples, 1476 – Piccard Watermark Collection Inv. No. 156036

Every Best Wish for a Sweet Sixteen


February 19th, 2015 § Comments Off on Rust § permalink

A number of artists today use rust in their works. Tony Reason’s are the most beautiful I’ve come across. Just below is an installation photograph of a show he had at the Kunstpavillon, Munich in 2005, and below that a work on paper. Reason’s works on paper are particularly interesting because he uses only rust and a support. In an email I explained my idea of making chalk from rust and calcium carbonate, and asked if I could link to his work. His reply was, “Please feel free to link to one of my Artworks. But my work is produced by direct contact with rust and not mixed with another medium.” (Link to Tony Reason’s site.) The scientifically minded might say that the moisture in air is the medium in Reason’s work, and art historians might say that he’s making monotypes with rust. However it is, the artworks show that rust can be used to powerful effect. Reason also uses copper corrosion.

Tony Reason - Exhibition Photo

Tony Reason – 2005 Kunstpavillon, Munich – Exhibition Installation Photograph


Tony Reason - Copper Sky - 2006 - iron, copper on paper

Tony Reason – Copper Sky – 2006 – Iron, copper on paper – 60 x 90 cm


Copper corrosion was used in antiquity for pigments. Theophrastus (371-287 BCE), one of Plato’s students and a natural historian, wrote of wine lees applied to red copper to obtain verdigris in On Stones (Theophrastus/Calley & Richards 1956:57). Theophrastus, however, did not write of iron corrosion. Apart from texts relating to medicine, which show that iron rust, like hematite, was used as a drug, there’s hardly any evidence that rust was used in the ancient world, at least that I could find. But, there is some. Pliny the Elder (23-79 CE), in his Natural History, wrote of the Hellenistic sculptor Aristonidas exploiting the redness of iron rust in his sculpture of the mythical Athamas, after having killed his son.

Still, however, human industry has not failed to employ iron for perpetuating the honours of more civilized life. The artist Aristonidas, wishing to express the fury of Athamas subsiding into repentance, after he had thrown his son Learchus from the rock, blended copper and iron, in order that the blush of shame might be more exactly expressed, by the rust of the iron making its appearance through the shining substance of the copper; a statue which still exists at Rhodes.

Pliny, Natural History, Book XXXIV, chap. 40, 

Bostock/Riley trans./Perseus

The rust that Aristonidas used, just as much as Reason’s rust, are synthetic materials because they come from iron, the metal, which is itself synthetic, manmade, anthropogenic, artificial, fabricated, whatever word you want to use.

Slightly later in chapter XL, Pliny wrote that nature checks belligerence by having weapons corrode.

Nature, in conformity with her usual benevolence, has limited the power of iron, by inflicting upon it the punishment of rust; and has thus displayed her usual foresight in rendering nothing in existence more perishable, than the substance which brings the greatest dangers upon perishable mortality.

Pliny, Natural History, Book XXXIV, chap. 40

Bostock/Riley trans./Perseus

If we take nature to mean air and water, what Pliny writes makes sense. These are the two things, that together, invariably cause iron and steel to corrode. Of course, it’s not just weapons that corrode—plowshares and paperclips also corrode. I asked Professor Marco Tizzoni, an archeologist specialized in mining and metallurgy through the ages, about the Romans and whether they had steel. He told me that the Romans did not have steel, but reheated their iron blades and their tools, whereby carbon monoxide would enter the iron surface and create a steel coating.

That Pliny should frame iron’s lifecycle in parallel terms to human mortality is what’s so interesting to me. Iron disintegrates. It can happen well within a person’s lifetime. It can also happen very quickly. Science teachers in today’s classrooms often use nails immersed in water, salty water, and vinegar to demonstrate chemical reactions. Iron’s corrosion is generally not a desired outcome, but once you get over the fact that it happens, rust makes itself available as a pigment.

Roman, c. 50 - 100 CE - Grave Stele Showing Blacksmiths at the Forge - Museo Archeologico Nazionale - Inv. 166 - Aquileia - w. 120 cm, h. 74 cm, d 24 cm

Roman, c. 50 – 100 CE – Grave Stele Showing Blacksmiths at the Forge – Museo Archeologico Nazionale – Inv. 166 – Aquileia – w. 120 cm, h. 74 cm, d 24 cm

The simplest rust pigments, those made from corrosion, and helped along with water or vinegar can be undertaken by any craftsman or anybody. The colorant should probably be thought of as a no-cost or low-cost urban solution. The earliest people working iron lived near the ore, the hematite, so they would not have been interested in rust as a colorant. Rust probably just perplexed and angered them. However later, when smithery became a trade in towns and cities, and when ingots of iron were sintered and smelted far away and brought to populated areas, rusted iron, even though just as maddening, could at least be recycled into a colorant. When iron axes, saws, chisels, trowels, hammers and nails became instrumental for work in the building trades, is when I believe rust was used as miltos tektonike, the red earth of builders. 

A few hundred years into the Iron Age, Hesiod wrote of the bleakness of his Age. In Works and Days, he wrote:

For now truly is a race of iron, and men never rest from labor and sorrow by day, and from perishing by night; and the gods shall lay sore trouble upon them.

Hesiod, Works and Days, Evelyn-White trans./Perseus

Iron’s nature—its inevitable dissolution to rust—insures that work never ends.

The goodish news is that rust is the antecedent to modern synthetic iron oxide colorants, and that at least by the 15th century, rust was given the more poetic name Croco di Marte/Crocus of Mars. The crocus part refers to the rust-red stigmas of the fall-flowering and pale purple flowered saffron crocus. Mars was both the god of war and iron and the significance clear. Next posts will be about rust, as well as by-products of iron smithing.

Season’s Greetings

December 24th, 2014 § Comments Off on Season’s Greetings § permalink

Season's Greetings - 2014





Bandinelli Self-Portrait with Red Chalk

October 24th, 2014 § Comments Off on Bandinelli Self-Portrait with Red Chalk § permalink

Donatello, Michelangelo, Cellini: Sculptors’ Drawings from Renaissance Italy opened yesterday at the Isabella Stewart Gardner Museum in Boston. The show, curated by Oliver Tostmann, runs until 19 January 2015. Some of the highlights of the exhibition are viewable on the museum’s site. What caught my eye was Baccio Bandinelli’s painted self-portrait from c. 1545. The oil on panel shows the artist pointing to his large red chalk drawing of Hercules and Cacus. It also shows him with a piece of red chalk. What’s interesting is that the chalk is cylindrical. It must either have been made in a mold or by rolling. It would be very very difficult for a piece of red chalk to be sawn from the ground and be rounded in the way it is.

Baccio Bandinelli - Self-Portrait - c. 1545 - oil on panel 142.5 x 113.5 cm - Isabella Stewart Garnder Museum - Boston

Baccio Bandinelli (1488-1560) – Self-Portrait – c. 1545 – Oil on panel – 142.5 x 113.5 cm – Isabella Stewart Gardner Museum – Boston

Bandinelli Detail - Isabella Gardner Stewart Museum - Boston

Baccio Bandinelli – Self-Portrait – Detail – Isabella Stewart Gardner Museum – Boston

Bandinelli holds the chalk in his fingers, without a chalk holder. Another painting in the exhibition represents Giambologna seated at a table with drafting materials. One of the instruments is a chalk holder with red chalk. The painting can be seen on the Gardner’s site.

Mattioli – Chalk Made from Common Armenian Bole & Stuff

August 31st, 2014 § 2 comments § permalink

Some of the most beautiful red chalk drawings of all time were created in Italy in the late 15th century and 16th centuries. They document the great range of chalk colors used by artists. The drawings show that some chalk was more lustrous, some was harder and left a more precise mark, and other chalk was thicker and more powdery. This doesn’t begin to explain the variety.

Unfortunately, the written record on red chalk is very slim in the 15th and 16th centuries. Leonardo writes of it in his notebooks (see earlier post). Vasari provides some detail in his Vite, writing that it came from the mountains of Germany. Armenini discusses red chalk at some length, but never says where it comes from. Other art historical texts hardly provide any amplification. There are no references to Italian quarries or places where it was found, and we can’t find any similar chalks in Italy today. But, if you look outside of art historical texts, there are references. This post looks at what the 16th century physician and naturalist Pietro Andrea Mattioli (1501-1578) writes about red chalk. Here is what he says:

THE STONE/CHALK called Hematite, that is blood-red, which is commonly called Chalk, and very well known to everyone & we have in Italy very many versions in the pharmacies, not only for use in medicine, but also by painters, by woodworkers, & by tailors, to be put to use for drawing, & for the marking of various lines. However, this is not the one which Dioscorides and Galen meant, because what’s in common use is counterfeited from common Armenian bole, & other mixtures/stuff. It happens that the true one is found to be a mineral, which when broken open, one sees the vivid color of blood, from which it’s gotten its name: because the Greeks called blood haema.

Discorsi 1555:661

The context is his entry on hematite from the book, Discorsi nei sei libri della materia medicinale di Pedacio Dioscoride. I’m using an online edition (Vinegia: Valgrisi, 1555). Essentially, the book tries to makes sense of what the physician Pedanus Dioscorides (c. 40-90 AD) was writing about in De Materia Medica, matching the plants and minerals to their names in Italian, where they could be sourced, and how they should be employed. Mattioli translations of Dioscorides’s text appear just above Mattioli’s comments, which are italicized. Mattioli also examines what other doctors, such as Galen of Pergamon (c. 130 – 200 AD) wrote. Galen, like Dioscorides, was Greek-born and educated, but practiced in Rome.

Agostino Carracci - Pietro Andrea Mattioli - Louvre

Agostino Carracci ( 1557-1602) – Portrait of Pietro Andrea Mattioli – Black chalk underdrawing, pen and brown ink on paper – 195 x 192 mm – Louvre ref. no. 11973 – Paris

Mattioli generally wrote in Latin, but he wrote the Discorsi in Italian as to make Dioscorides’s Greek text intelligible to a wide readership. It was a reference book, a pharmacopoeia for doctors and pharmacists, but it was also for the broader public. I used to look at my father’s Merck Manuals, and look is the better word than read. While I miss a lot in the Discorsi, it is less difficult to understand than the Merck Manual. The Discorsi went through numerous printings and was translated into other languages. The first edition came out in 1544, where it is known as cinque libri/five books, following Dioscorides’s five books. The sixth may be may not be by Mattioli. It deals with snake bites, which had been discussed in the earlier books, and sounds like a publisher add-on to push the book. The hematite entry appears in the fifth book, so we don’t have to concern ourselves with this. In earlier editions, he does not say where the chalk comes from, nor who uses it, but he says it’s very commonly available. Starting about 1553, he describes who uses the chalk and refers to counterfeit chalk until at least 1563. By 1568 or so, he revises the counterfeit part, writing, “…the one in common use is soft like clay, & is to be found in open mountain areas.” (Discorsi 1568:1443) Since the Discorsi was reprinted many times, and Mattioli made frequent revisions, I would need to get to a/some very well furnished medical library/ies and systematically go through them to know for sure when and how the hematite entry changed over time. I haven’t done this. First, it’s worth trying to understand what he’s talking about in the 1553, 1554 Latin ed., 1555, 1563, editions, which I have looked at online, where the entry on hematite reflects the above block quote.

Italian Pharmacies (Spezierie)

Mattioli lived in a number of Italian cities, and as a famed doctor would have traveled to others to attend to patients, meet with other doctors, visit his publishers etc. (He also lived in Prague, where he was doctor to the Habsburg Archduke Ferdinand I and Holy Roman Emperor Maximilian II.) Since he was a physician he would have been intimately aware of what pharmacies stocked. Italian pharmacies, in addition to selling the plant, mineral, and animal based medicines that were central to their business, also sold pigments and dyeing agents. The chalk shows there was crossover between medicinal and art supplies. Gold is another item that was used both in medicine and in art. Artists bought their supplies at pharmacies. (Vendecolori, literally color vendors, was a budding profession in 16th century Venice. Louisa C. Matthew wrote an interesting article on the subject. She writes that vendecolori was a profession peculiar to Venice.)

Binders were used by the pharmacists, by artists, and by the public at large. In my last post, I listed the 32 binding agents that were in the 1498 Florence Nuovo Ricettario Fiorentino (online text and excellent index courtesy of Olimpia Fittipaldi), as to what a pharmacy should stock, in addition to the core prescription recipes. Binders were important for the work of the pharmacy itself—they needed binders to compound the pills they sold, the irregularly shaped pills known as trocisci, and also for the chalk they put together for medicinal use and for use by artists, woodworkers, and tailors. The amount of binder in chalk influences its hardness. The more binder there is, the finer and crisper the lines. Sharpening also influences line weight. Artists used chalk of different consistencies, mainly placing it in a chalk holder, called or toccalapis or matitatoio in Italian. The chalk for woodworkers, as in lumberyard workers and carpenters, would probably have been broader and they could have gotten away with using a lump in the hand to draw and snap lines. Tailors may or may not have used a holder. Their chalk would have been more powdery or friable. Tailors today use a variety of colors, including red. If there was red chalk remaining on the fabric after brushing it away, they could have cleaned the residual chalk with some lightly acidic liquid. Leonardo writes in the Institut de France MS F, fol. 96r  of using wine, vinegar, or aqua fortis for dissolving chalk, before forming it again with a weak binder.

If you read manuals such as Girolamo Ruscelli’s Secreti del Reverendo Donno Alessio Piemontese (Alessio Piemontese was his pen name for this book), you get a sense of the problems of storing loose pigments. Girolamo Ruscelli (c. 1518 – 1566) was a contemporary of Mattioli’s, and was a humanist/literary critic and cartographer. There are sections of the book on medicinal remedies, beauty recipes, directions for making writing and art materials, faking gold and precious stones, and a good deal else. It’s often described as a book of alchemy, and it is that in a very broad sense. Since so many of its entries have practical home applications, such as directions for removing spots from clothing, maybe it is better to say that it’s a book of alchemy and household science. Anyway, it’s a very entertaining how-to manual, and it gives an idea of how industrious people were in the 16th century. He describes everything with such terrific enthusiasm that you want to get to work carrying out his projects. Perfettissimo/most perfect is how he terms the results, and he continuously reminds his readers how much money they are saving by carrying out his secrets. The book had an enormous success.

The Secreti reveals how people were making use of the many gums and glues available at their pharmacies. About pigments, he cautions his audience to store them carefully in suede pouches or well sealed boxes, so as to avoid having the powders fly away. He sometimes gives directions for pigments, for cosmetics or art use, to be formed into pieces or loaves. His directions, for example, for artificial cinnabar loaves comes under the title and heading “To Make Cinnabar, To Make Loaves Of It, of one hundred or two hundred libre, or as big as you wish, like the ones that come from Germany. Until now no one in Italy has known how.” (Secreti 1555:197). It may be that Ruscelli was using expensive quicksilver to arrive at German artificial cinnabar loaves, which may instead have been red chalk. Cinnabar was very often faked. Cennini writes of cinnabar faked from ground bricks and warns his readers to always buy cinnabar whole (Milanesi Cennini 1859:27). From the way Ruscelli writes about pigments, you get the impression that pharmacies would have particularly liked to sell pigments in pieces or clumps since they could handle and package it more easily. They could have wrapped it in paper, thereby avoiding the expense of providing a suede bag for every purchase. The binder would have been weak, so the client could again reduce it to a powder with a few blows of the pestle.

When the pharmacies started selling the chalk suited to the needs of the various professions would be interesting to know. The 1498 Ricettario does list lapis emathites, and it gives formulations that include hematite. Whether they were referring to true hematite chalk or its counterfeit is impossible to say. Leonardo made his own hematite chalk. He didn’t seem to have any trouble experimenting and making things, and he may not have liked what was available at the pharmacies. Piero della Francesca was also an early user of red chalk. See the Biblioteca Reggiana manuscript De propsectiva pingendi MS A 41/2, fol. 26r.

Ricettario Fiorentino - 1574  - Frontispiece

Frontispiece  – 1574 Ricettario Fiorentino  – Giunti

 As other Italians of his period, Mattioli refers to chalk as pietra and lapis. The words can also refer to stone, and it’s worth thinking about whether the terms for chalk refer back to the mineral origin of chalk, or whether the chalk itself looked like stone. It’s probably a bit of both. Maybe the chalk available at pharmacies was formed into individual rock-like shapes, although I think it is more likely that it was made in large batches and then broken into chunks. The other commonly used word for chalk was matita. According to the Accademia della Crusca’s dictionary, the word first appears in print in 1528. It definitely refers back to the mineral hematite, but only implied chalk. (In current usage, it implies pencil or chalk.)

The 1528 use of the word matita comes in a comic play by Ludovico Ariosto (1474-1533). The exchange is in La Lena and appears in Act III, Scene 8.

Fazio: La matita prendere potete, e notar questo./Take up the chalk you can, and note this.
Torbido: Io lo noto, eccolo./I note it, here it is.

The lines aren’t particularly interesting in themselves, but the word matita gains relevance when you understand Torbido’s profession. He’s a perticatore/surveyor, and the characters are measuring a room in the scene. A surveyor would use pen and ink for finished documents, but in the field they used chalk to make marks on walls to measure from point to point. They would also have used chalk to draw rough ground plans and property boundary lines in a notebook. It is also where they would write down the measurements crucial to their work. Chalk, in essence, is a vehicle for pigment and something that’s highly portable. Surveyors might have made their marks with a brush and paint and notations with pen and ink, but chalk was much easier to handle. Similarly, a pill, is an efficient delivery system. Pharmacies, in the past and today, could just dispense a container of loose powder medicine and instruct the client to shake the container and take out however many spoons. Pills, and the trocisci antecedents, insure that the ingredients are equally divided into doses. Like chalk, they’re easy to handle and also highly portable.

Hematite and Armenian Bole

Because Matttioli uses the words contrafatta/counterfeited about the chalk, it’s clear that he would have avoided prescribing imitation of hematite chalk in the pharmacies. He also describes it as containing misturaggini, which I’ve translated as mixtures/stuff. This word also has bad connotations. Mistruaggini sounds as if it’s the equivalent of current usage miscuglie. I’ve heard many Italians speak of food that they didn’t like, and especially of food consumed on trips abroad, disparagingly say, “Certe miscuglie!”. The English translation would be, “What a hodgepodge!” or worse.

According to Mattioli, hematite was reduced to a powder with a grinding wheel. He relates that it was prescribed for, among other conditions: eye disorders, including bloodshot eyes; menses issues; and the spitting up of blood. Prof. Marco Tizzoni, an archeologist focused on ancient iron mining, says that hematite has bacteriostatic properties. I don’t see that hematite has uses in 20th or 21st century medical practice. People today, mostly iron miners, are treated for conditions resulting from occupational exposure to hematite. Mattioli’s entry on hematite is in some ways strange. He completely misses Elba as the prime source for hematite. This is particularly odd since he was Tuscan and because he does say Helba was a source for armenian bole. Armenian bole is essentially kaolin, and kaolin is used in modern medicine, however it’s mainly used in the ceramics, cosmetics, and paper industries.

Today we mostly think of armenian bole in terms of the material that gilders use. It’s the cinnamon-colored tacky base onto which gold leaf is applied. It was also used in that way in Italy. The 14th century artist and treatise writer, Cennino Cennini writes of bolo armeniaco for applying gold leaf to paper in his Libro dell’arte (Milanesi, 1859:110). The color of gilding bole, or kaolin, is due to  impurities from its contact with iron.

Kaolin, caolino in Italian, is a word that comes from Chinese (gāolíng/high hill). In English it’s also known as China white clay and porcelain clay. The word kaolin entered European vocabulary in the 18th century, so we shouldn’t expect to find the word caolino in 16th century texts. Among the terms that Mattioli uses for kaolin are: terra sigillata, terra di Lemnia, bolo orientale, bolo Armeno, and bolo Armeno commune. These were used to treat a host of ailments, from plague to snake bites. Modern medicine uses kaolin in some of the same ways that Mattioli and Dioscorides used them. Mattioli writes of kaolin and its use for dysentery, wound dressings, and mouth ulcers. Today it’s used for upset stomach; the Mayo Clinic has an interesting page on the reappearance of tourniquets, sometimes impregnated with kaolin; and it is given to patients undergoing radiation treatments, for the side effects of mouth swelling and soreness.

Mattioli spends a great deal of time puzzling about what Dioscorides and Galen meant in their discussion of these medicinal clays in relation to what was available to him. He examines the colors, he tastes them, and puts the earths on his lips to match them up to earths of the ancient doctors. Since kaolin is naturally fine it would have required less grinding than hematite. The colors could be white, red, or yellow and the colors in between. Professor Tizzoni tells me that he has even seen kaolin with a green cast. The color depends on its proximity to coloring minerals.

The terra sigillata/sealed earth, of which the terra di Lemnia was one, were the most prized and the most costly. They were the ones imprinted with symbols meant to insure place of origin. The Lemnian earth came from island of Lemnos in Greece. Dioscorides writes of the Lemnian earth as being mixed with goat kid blood and bearing a seal with a goat. By Mattioli’s day the island was under the part of the Ottoman Empire and sealed earth bore words in Turkish characters. In ancient times it was supposed to have been collected and formed into cakes by an Hephaestia priestess and her helpers. The town of Hephaestia takes its name from Hephaestus, god of fire and the forge, who was believed to have  particularly favored Lemnos. The sealed earth cakes bore seals of Artemis or her attributes, including a goat.

A vivid account of the island of Lemnos and the Leminan earth was written by H. Fanshawe Tozer in his Islands of the Aegean, 1890. The book was pointed out to me by Professor Tizzoni. Tozer visited Lemnos, which was then part of Turkey, and prepared himself for the visit by reading ancient authors. He particularly read Galen, who had visited Lemnos and collected 20,000 cakes of the Lemnian earth to bring back to Rome, and a later visitor, the 16th c. naturalist Pierre Belon. He writes of the unusual collection of people he meets, how Mount Athos and its shadow seem to loom, how it’s a place nearly devoid of trees except for fruit trees by the villages, and there are great stretches of medieval Genoese walls. When he arrives at what he believes is the correct site of the Lemnian earth, about a mile outside of Kotchino, it’s a bit disappointing. It’s a pit covered with thistle stalks, and when they dig they find what looks like ordinary clay. He sees none of the dull red earth that previous authors had described. Nevertheless, he hears accounts by locals and writes, “that when the ground is opened, the sacred earth wells up of its own accord–‘leaps up,’ ‘boils up’ were the expressions used…” (p.263) The customs written about by ancient authors and their similarity to the accounts he hears from local people makes Tozer think that he was in the right place. He also writes of Lemnos women who wore beaded necklaces made of clay and how they would grate off pieces of the beads for medicinal purposes. Tozer cites an analysis of the earth which found that it contained: 66% silex, 14.5% alumina, 6% iron oxide, 8.5% water, 3.5% natron, and inappreciable quantities of lime and magnesia, adding that one couldn’t be sure this was the original rubrica. (p.266) In recent years there’s been speculation that the Lemnian earth might have been bentonite or montmorillonite. Professsor Tizzoni in an instant message wrote, “I’m pretty sure T. Lemnia was kaolin. Bentonite and montmorillonite are quite common on other Greek islands such as Mylos and they were not sought after at all in ancient times!”

Mattioli was keenly aware of counterfeiters and he outlines a ruse by which phony terra di Lemnia passed through Constantinople. He goes to some length in discussing fake earths and how to tell them apart, but it must have been difficult. The marks on the sealed earths, like the hallmarks on precious metals, the words Parmigiano Reggiano on Parmesan rinds, and the word Pfizer imprinted on viagra pills, could easily be faked. Within the realm of drawings, there are spurious collectors marks, as for example the Eugène Delacroix estate mark Lugt 838.

Terra Sigillata - Germany - 1500 - 1700 -  Science Museum, London

Examples of Terra Sigillata/Sealed Earth | Germany | 1500 – 1700 | Science Museum | ref. no. A656712 | London | Wellcome Images

The common armenian boles would have come from Italy. The 1574 Ricettario Fiorentino writes of red armenian bole coming from the area of Volterra. The later 1623 edition of the Ricettario, writes of Elba as a source, confirming what Mattioli had written. The entry on Armenian bole reads:

From Elba we’ve had for very many years & happily used with much success the white earth & red & yellow: among which the white is the most excellent, and whose color is very similar to the Armenian Bole of Galen: after which is the yellow, & the red in the last place for internal medicines. But for medicines to apply to the exterior, the red is to be preferred since it is more astringent.

Ricettario Fiorentino 1574:24

Giovanni Targioni Tozzetti I, an 18th century Florentine doctor and naturalist, wrote that gilders could save themselves buying Elba armenian bole since it was present in Florence’s Cave di Lastre, the quarry for pietra serena in the Boboli Gardens, Nannuccio (?), and the Montici hill (near Pian dei Giullari). He also lists Fiesole and the more distant Golfolina as spots for finding common Armenian bole in his Viaggi fatti in diverse parti della Toscana per osservare le produzioni naturali e gli antichi monumenti di essa (1751:16-17). Professor Tizzoni has related that there’s an abundance of kaolin in Tuscany’s Roccastrada, a town inland and north of Piombino. He said that there was also a great deal of kaolin in the territories of Vicenza, which was exhausted in the 20th century. In any case, there was, and there still is, a great deal of kaolin  in Italy.

Kaolin and Fogg Conservation Study

Mattioli relating that common armenian bole, or kaolin, was used to fabricate the chalk is significant since conservators who have studied the composition of old master and 19th century red chalk drawings, have found kaolin in red chalk. I’m referring to an interesting conservation study carried out at the Fogg Art Museum in the mid-1980s. Debora D. Mayer and Pamela B. Vandiver published their paper “Red Chalk: Historical and Technical Perspectives/Part 2 Technical Study” in Drawings Defined (Abaris, 1987:171-179). The paper was delivered first at a 1985 symposium on drawings, sponsored by Ian Woodner. The study is particularly interesting for its discussion of the platelet particles common to both hematite and kaolin. Mayer and Vandiver sought to determine the differences between natural, fabricated, and synthesized red chalk. They also wanted to establish when synthesized chalks made from synthesized iron oxide began to be manufactured. For their study they took minuscule amounts of chalk from drawings and also examined actual pieces of red chalk, one of which was from Lascaux. They studied at least two Italian drawings, one by Pietro Faccini (1562-1602) and another by Giambattista Tiepolo (1696-1770), but I can’t say how many of the total of 17 drawings were Italian. I also can’t tell if they had a piece of Italian chalk. The chalks showed, in Vandiver and Mayer’s words:

Of the samples studied, the proportions of hematite to clay varied from 50-80% hematite and 20-50% clay. Most often hematite and clay were present in equal proportions. Clay alters the color of the chalk to a lighter tint, but more importantly, it eases the spread or flow of the chalk onto the paper, often referred to as softness. Kaolin is the clay most often used. It is a family of fine white clays with a platey particle shape and particle size of about one to ten microns (a micron is a thousandth of a millimeter).

Drawings Defined 1987:173

The chalks such as Leonardo’s “lapis amatita macinata” or ground hematite chalk would have had a greater proportion of hematite to clay. See prior post, where the Kremer Pigments composition for natural hematite lists 80% iron oxide and the remainder amounts to clay. The chalks, such as the Mattioli’s counterfeit bolo Aremeno commune and misturaggini (red ochre) would have had a greater proportion of kaolin than the hematite chalk. Common red armenian bole would bring some iron oxide and the red ochre would bring more, but still less than a straight hematite chalk.

Unfortunately, binders were not something they looked at because they wrote that it wasn’t possible with the analytic methods they used (p.174). On the same page they relate that clay and water have enough binding power to bring together a piece of chalk. Since the Fogg study was undertaken, I believe there have been advances in identifying binders, especially protein based binders, but plant ones as well. It would truly be excellent to be able to identify, for example, the 32 binders listed as common in the 1498 Ricettario Fiorentino.

Mayer and Vandiver found that the difference between natural and fabricated chalk is that fabricated chalks show evidence of being milled. Now, the common armenian bole which Mattioli writes about would have needed minimal milling since it was fine by nature. It would have had to be cleaned. In industries, such as the paper industry, they use the word slurrying to denote soaking kaolin. Kaolin is used in paper to give body and also gloss to the surface.

Antoine Lomet’s indications for making chalk (see Making Hematite Chalk post) gives the followers of his recipes the choice of grinding, or soaking the sanguine or iron oxide red pigment in water until it is impalpable. Impalpable is a lovely word, more a word of another era. I recently made some hematite chalk following Lomet’s instructions. Sludge is the less nice word that came to mind for the ground hematite that I left to soak in water for 24 hours. After soaking in the water, it’s completely smooth and there is no graininess at all. It is impalpable. How much evidence of milling is apparent after soaking hematite, hematite-rich red ochre, or kaolin is something to think about.

Mattioli uses the word impalpabile in his entry on hematite, although he does not speak of wetting it. Leonardo uses the word impalpable several times in his notebooks. In Madrid II, fol. 141r he writes of soaking coarse sandy earth to make a mixture suitable for casting. He calls the resulting mixture quasi impalpabile/almost impalpable. As one of the possible colorants to the earth he lists iron rust. Giovanni Battista Armenini’s chalk was made with rust—for a truly junk chalk. I believe this is rubrica fabrili/ironsmiths chalk and will work on a post about Armenini. Ruscelli writes of impalpable earths in terms of making casts, and for other purposes which he doesn’t specify. His instructions call for numerous grindings, but also involve soakings and water changes. He says his directions make for earths that are, “sottile come l’aria” or “as fine/thin as air.” (Secreti 1555:208.)


There may have been fillers in the chalk. Something that would have cost even less than common armenian bole. Gesso, or gypsum, might have been used. The common armenian boles have a nice red-brown color, but not the color of blood-red hematite–what pharmacies were duping. To make the chalks redder they added hematite-rich coloring earths, that is red ochres. Italy is full of red earths. The Tuscans says the iron in the soil which makes it red, also accounts for their good wine. In Campania, Liguria, and the Veneto you can see that they have red ochres because of the colors their buildings are painted. And they’re beautiful. Even if the traditional paints may now be artificial and come in plastic tubs from worlds away, in the past the colors were used because they were nearby and easily had. Here are some red ochres attached to places: terra di siena, rosso pozzuoli, rosso ercolana, terra di verona, and rosso di venezia. Harvard’s Forbes Pigment Database, hosted by Boston’s Museum of Fine Arts site, lists others from Italy and elsewhere. Lombardy and Emilia, where many red chalk drawings were made, are not known for red ochres, but since they’re more or less sandwiched between Liguria and the Veneto, red ochres were close by. Emilia Romagna also borders Tuscany. Rome, another place where many artists used red chalk, has Tuscany to the north, and Campania directly to the south.

Some red chalk drawings are raspberry-red in color. Those chalks were probably made with a paler kaolin. I have a feeling that it would be difficult to arrive at those clear reds with the muddier brown-red kaolin. One would have to experiment to see.

Professor Tizzoni suggested that they might have added beeswax or animal fat to the chalk to have it better adhere to paper, or wood. If they did use animal fat, the 1498 Nuovo Ricettario (pages 58 & 59) has very many of those. Here’s the list of the twenty Grassi Usuali/Common Fats, first in Italian, and then English: Sugna di porcho, Grasso di chavallo, Grasso di gatta, Grasso di tasso, Grasso di avoltoio, Grasso di chane, Grasso di volpe, Grasso di chapra, Grasso di nibbio, Grasso d’anitra, Grasso di gallina, Grasso d’asino, Grasso di lione, Grasso di beccho, Grasso d’ocha, Grasso d’orso, Grasso d’anitroccholo, Grasso di serpe, Grasso di talpa, Grasso di ramarro. (Pork, horse, cat, badger, buzzard, dog, fox, goat, kite, duck, chicken, donkey, lion, skimmer, goose, bear, duckling, snake, mole, lizard.) I’ve pondered having the choice of taking hematite or counterfeit hematite chalk, and decided that the counterfeit drug might be better. The variable of animal fat adds a new dimension to the problem, and makes it much tougher to figure out. The good news is that the same pharmacies carried delicious sounding fruit syrups, with which one could chase down either choice. For the eye solutions, one would want someone else to administer it, so as to avoid looking in a mirror and seeing red liquid dripping from your eyes. The pharmacies also sold delicious sounding candied fruits.

Soft Clay-Like Chalk in Open Mountain Areas

In later editions Mattioli says that soft clay-like chalk comes from open areas in the mountains. Were it to be used as a medicine and for making marks, it would have to have been cleaned and washed of its grit, seeds, lichens—the sorts of things that blow about in the mountains. I asked Professor Tizzoni what to make of Mattioli’s revision about chalk coming from the mountains. He said, “It means he was out walking in the mountains and saw something that reminded him of the chalk in the pharmacies and he revised what he’d written.” There it is. He was walking in the mountains and saw something that looked like the chalk in pharmacies.

Ulisse Aldrovandi (1522-1605), the Bolognese naturalist, collector of natural specimens, and professor carried on a correspondence with Pietro Andrea Mattioli. In his Musaeum metallicum in libros IIII, published posthumously, he does not report Mattioli’s mountain origin. Instead, he writes:

Painters & certain woodworkers (probably cabinetmakers) use Hematite for drawing, and they call it lapis/chalk. Mattioli denies that this is real Hematite, instead he asserts that it is an imitation made with common Armenian bole and other fake stuff.

Metallicum 1648:653

The open mountain origin explanation cannot account for the very many types of red chalk in Italy’s pharmacies that Mattioli saw or the very many types of Italian red chalks we see in drawings in public and private collections. Instead, imitation hematite chalk, true hematite chalk, rubrica fabrili, and chalk from outside of Italy can explain the varieties of red chalk we see in Italian old master drawings.

Cibo – Notes on Mattioli

Mattioli was a friend and correspondent of Gherardo Cibo (1512 – 1600), the draftsman and botanist. Cibo also carried on a correspondences with Ulisse Adrovandi. In 1580 Francesco Maria II della Rovere asked Cibo to color and embellish the woodcuts in his edition of Mattioli’s Discorsi sulle piante e sugli animali. Della Rovere’s edition is now in the Biblioteca Alessandrina in Rome. Arnold Nesselrath and Katia Lysy published a book on the edition in 1991.

Mattioli died of the plague in the early months of 1578. Kaolin was a prime medicine for plague. No amount of the finest, costliest terra sigillata would have helped him. It could have aided some of the symptoms, but not the disease. If it were viral, he didn’t have the antibodies to fight it and vaccines were only coming into use in the 19th century. If it were a bacterial plague, he, again didn’t have the necessary antibodies, and only 20th century antibiotics would have helped.

Because of reading about Mattioli, which I would not have done except for red chalk, I found out that the genus of flowers called Matthiola, was named after Mattioli. The genus of the Brassicaceae family includes stock. I could recognise the name Matthiola from my dead of winter habit of reading/dreaming over seed catalogues, but never looked into the why of the genus name. I was happy to have found out Mattioli’s connection because these flowers have always been some of my favorites. When I was a student I’d buy stock, Matthiola incana, to get me through nightmare exam weeks. Their colors, perfume and gray-green leaves are very close to heavenly. Materia medicinale per eccellenza.

Many thanks to Professor Tizzoni for reading and translating passages from Aldrovandi’s book and so much else.

Making Hematite Chalk Crayons

August 7th, 2014 § 1 comment § permalink

In 16th century Italy the words matita and lapis were used interchangeably for the word chalk. One of the things I’ve been working on is linking the word matita to the Italian word for hematite. Amatita and amatista are the usual words given in earlier texts for what’s now known as ematite in Italian.

I’ve been particularly focusing on Italian red chalk drawings. The widespread view about red chalk is that artists in Italy began using naturally occurring red chalk in the late 15th century, and that it was replaced by fabricated red chalk, first made in France in the 18th century. The problem with this view is that there is a tremendous variation in color in the red chalk drawings of Italian artists, and references to where the red chalk came from is essentially absent, with the exception of Vasari, who locates the origin to the mountains of Germany. (Post on Vasari and red chalk later.) Naturally occurring art materials very often are paired with geographical indications, such as terra di pozzuoli, terra di siena, bolo armeno and others, but there are no references to lapis di … or matita di … and, to me, this is significant.

Hematite is a major ore of iron, and for a while I was entertaining the idea that red chalk could be a byproduct of iron mining, thinking that the boom in iron (used principally for armaments) coincided with the use of red chalk. That Leonardo and Francesco di Giorgio Martini (see drawings in British Museum, catalogued as having brown chalk underdrawing), could be connected to iron production, and the design of weaponry, seemed interesting. Because of this, I contacted Professor Marco Tizzoni, (cv and publications). He is an archeologist, whose main focus is historic iron mining and metallurgy. Tizzoni recently retired from the University of Bergamo, and is now training archaeologists in ancient mining and metallurgy for the National Archaeological Service of Lombardy (Soprintendenza Archeologica della Lombardia). Our email exchanges and Skype conversations have been invaluable to me.

Professor Tizzoni quickly set me straight. He very patiently explained how matite could not be byproducts of iron mining and smelting, saying, “…. slags are very hard indeed and virtually eternal (it’s funny but man seems to be able to make eternal nasty stuff only, such as slags and plastic).” He seemed even a bit surprised that anyone should think that matite could be anything but fabricated. He went on to say, with more generosity towards mankind, that earlier artists were fully capable of making their own, and that nowhere in Italy could red chalk suitable for writing and drawing be quarried, mined, or dug from the earth. He also added that he is not an expert in writing and drawing materials. My side of the conversation went something like, I know that those artists were very smart and capable of making chalk, and I’m not that dumb that I can’t understand that, but I’ve read over and over again that they were using natural red chalk. Byproduct chalk had seemed like a good possibility, but after conversing with Professor Tizzoni, I had to let that idea go.

Professor Tizzoni then said that I should make my own chalk, that I should experiment. Because of Leonardo’s reference to “lapis amatita macinata” in Institut de France MS A, 104r (link to post), I had looked for recipes for hematite chalk and because of Tizzoni’s encouragement, I’ve made some. It’s a definite plus that there were only three ingredients involved: hematite, water, and gum arabic or fish glue.

The first recipes I found were in English publications, and date to the 1820s. The English recipes, always essentially the same and never attributed to an author, appeared in periodicals such as the Edinburgh Philosophical Journal (1825); and  Iron: An Illustrated Weekly Journal for Iron and Steel Manufacturers, Metallurgists, Mine Proprietors, Engineers, Shipbuilders, Scientists, Capitalists… (1826). After finding the English recipe, I found Italian ones, as for example Lorenzo Marcucci’s Saggio analitico-chimico sopra i colori minerali e mezzi di procurarsi gli artifatti, gli smalti, e le vernici (1816). From the Italian publications, I could see that a certain Sig. Lomet was credited with the recipe, and then looked for his work.

 Antoine François Lomet des Foucauds (1759-1826), who shortened his name for his publishing activities to A.F. Lomet, was an engineer who taught architecture for a short period at Paris’s École Polytechnique, and served in the French military. His recipe, from which a great many others spring, credited or not, is in his article, “Sur la fabrication des crayons de pate de sanguine employés pour le dessin,” Annales de chimie, ou, Recueil de mémoires concernant la chimie et les arts qui en dépendent, (Paris: Joseph de Boffe, 1799), ser.1, v.29-30 1799. His crayons were supposed to be similar to the fort cher chalk of a firm called Desmarest, which must have been a competitor to Conté. He says the cost of making the chalk amounts to a quarter of the cost of Desmarest’s. The recipe’s prime ingredient is sanguine sechè, but oxide rouge de fer is listed as a substitute.

Only recently did I find an English translation from 1800 of Lomet’s article. It appeared in the A Journal of Natural Philosophy, Chemistry and the Arts, Volume 3. It must be because I was fixated on hematite, and in the translation they write ocher or red oxide of iron, that I didn’t find it sooner. I wish I had. Lomet also gives the recipe in ounces and grains (time of metric changeover), which may be found in the article linked above. Here’s a screenshot of the recipe in English, which gives only metric measures.

Screen Shot 2014-08-05 at 15.47.41

Lomet’s Recipe for Chalk Crayons

The important thing about the recipes is that they contain the barest number of ingredients, with no fillers. Hematite surely was increasingly available in 15th and 16th century Italy because of iron mining, particularly in Tuscany and Lombardy. Gum arabic was also widely available.

Just below is an image of the hematite chalks I made. The one on the left was made with 50 grams of hematite and 2.2 grams of gum; and the one on the right with 50 grams of hematite and 3.1 grams of fish glue. I don’t have a scale for small measures, so the amounts should be seen as approximate. Since I’m making the chalks in such small amounts and don’t have the equipment, I have not shaped the chalk by putting it into molds or injecting it into cylinders, as Lomet indicates. I briefly tried stuffing some of the damp chalk material in a piece of tubular pasta lined with baking parchment paper, but soon gave up. The gum one on the left has dried out a bit since I made it. It has become harder to manipulate. Clearly, there’s room for improvement in both types. In the center is red chalk, possibly from Poland. Zecchi, from whom I bought it, wasn’t sure if it was Poland or some other Eastern European country. I do not yet have a porte-crayon and haven’t sharpened any of the chalks.


Hematite Chalk Gum Fish Glue

Top: gum arabic grains, ground hematite, fish glue sheet; Bottom: gum arabic chalk, Zecchi natural red chalk, fish glue chalk

I’ve tried writing on a window with both the gum and fish glue variations, but have not succeeded in leaving a mark. I will try and find some old glass to mark and also to make a softer chalk, using less binder, to try and half follow the glass exercise in Leonardo’s lesson from Institut de France MS A, folio 104r.

The hematite, gum arabic, fish glue, grinding slab and muller were also ordered from Zecchi – Colori – Belle Arti. I learned that their hematite comes from Russia. Massimo Zecchi said that years ago they used to collect hematite from Elba to sell, but the area where the iron quarries were, had been fenced off, and that they hadn’t been back to Elba in many years. Ideally, I would have used Elba hematite, but I haven’t seen it for sale. Professor Tizzoni related that I could buy it from a shop specialized in mineral specimens, which I may eventually do. The idea of grinding down a chunk is a little off-putting (my grinding ability is poor and I lack attention span), although he says hematite can be soft, and even flaky. If I do buy some, I’ll buy it at a shop, where I can feel how hard it is, and not online.

Kremer Pigments also sells natural hematite, both in lump and ground form, and because they list the composition for the ground hematite, I had wanted to order some from them, but they having a warning about its being only for professional users. Nevertheless, to give a general idea of what makes up hematite, below is the composition list of Kremer hematite. I’ve added the column labelled “spelled out,” because, unfortunately, I’ve barely studied any science.

Kremer Hematite -Chemical composition 


Spelled out



iron (III) oxide



silicon dioxide or silica



aluminium oxide



calcium oxide



magnesium oxide



potassium oxide


< 0.1 

titanium oxide


< 0.1 

phosphorous pentoxide


< 0.1

manganese dioxide


< 0.05

sodium oxide



carbon dioxide

H2O (struct.)




< 0.05

sulfur trioxide

I haven’t yet looked at recent conservation studies on the composition of red chalk, but have looked at a paper by Deborah D. Mayer and Pamela B. Vandiver, delivered at a Woodner symposium at the Fogg, and published in the book, Drawings Defined (1987). A pair of sentences in their “Chemical and Structural Analysis of Red Chalks and Hematite,” reads, “Of the samples studied, the proportions of hematite to clay varied from 50-80% hematite and 20-50% clay. Most often hematite and clay were present in equal proportions.” The Kremer Pigment hematite reaches the upper limit. My next post will be about a 16th century source, where kaolin, a clay, is listed as the central ingredient, and the proportion of hematite or hematite-rich material would be smaller. Kaolin is often described in terms of platelets. Mayer and Vandiver use the word platey in their study and see this characteristic as a hallmark of naturally occurring red chalk.

Professor Tizzoni, over the years had collected a great deal of hematite. He recently gave his collection to the University of Pavia, where they are mapping hematite, looking at the chemical composition, the markers, to compile a database on the mineral and its places of origin. He has also collected hematite for France’s CEA (Centre Energie Atomique), which is conducting a similar study. I asked him why my hematite was more brown than red in color. He said that it could be because of impurities, and went on to say, “According to my experience when the ore is shiny, flaky, iron gray and in large crystals its powder is red, when it’s black, opaque, microcrystalline its powder is brownish.” In the same email he added, “Once we made a survey in a big and ancient hematite mine in Lombardy and not only at the end of the day we were entirely covered with shiny tiny flakes of hematite which gave us a rather peculiar look (something more fit for A Midsummer Night’s Dream, I’d say!), but also when we washed ourselves we gave the water a reddish colour.” Of course, I wish my hematite were redder, more like Lombard or Elba hematite, or even a redder Russian hematite, which he says exists. If my hematite were redder, the resulting chalk would look less like chocolate. If small children came to the house, it is something I’d definitely put away.

One further note, fish glue dries very slowly, much more slowly than gum arabic. Leonardo used fish glue in his practice, although I don’t remember it in reference to his chalk or pastels. For the moment, the Biblioteca Leonardiana search term function isn’t working, but I think I remember his using the words “colla di pesce” about six or seven times. My first fish glue batch was disastrous. I used too much fish glue, which was particularly irksome since I blew a full 100 grams of  hematite of my 500 gram total. The resulting chalk is rock-hard and won’t write unless you dip it in vinegar. Then it writes for a short while. Leonardo talks about dissolving chalk in vinegar and then reconstituting it with weak glue/binder/gum* in Institut de France MS F, fol. 104r. Just below is a screenshot and below that is the translation by Jean Paul Richter:


Detail of Leonardo MS F, fol. 96r - reversed - aceto ref

Detail of Leonardo’s Institut de France MS F, fol. 96r – reversed


Chalk dissolves in wine and in vinegar or in aqua fortis and can be
recombined with gum.

*Leonardo uses the term “colla dolce.” Dolce, while it sounds as if it should mean sweet, should instead be read as weak. Recently I’ve been looking at 15th and 16th century medicine-related texts. One of the most interesting is the 1498 Nuovo Ricettario Fiorentino (Bibilioteca Nazionale Centrale di Firenze, Palatino E.6.1.27)a manual providing guidelines as to what Florence pharmacies should stock, including such information as the shell life of items. Olimpia Fittipaldi, an Italian scholar, has transcribed the text of the Nuovo Ricettario and it’s available online in PDF form She also provides an excellent index. Under “Gomme Usuali” or “Commonly Used Gums,” (pages 56-57), the list reads: Myrrha, oppoponacho, pece nera, charabe, ragia di pino, incenso, mastice, bdelio, sandaracha, gomma di cedro, di finocchio, pece grecha, draghanti, trementina, colla di pesce, colla nera, euforbio, armoniacho, gommaedera, ruta, serapino, galbano, storace, gomma arabicha, gomma di abeto, gomma di vino vermiglio, gomma di vino biancho, di ciriegio amareno, di ginepro, di abezzo, pania, orochicho.” There are 32 types of binders. It’s an amazingly long list. As one would expect, the very common fish glue and gum arabic are present. I underlined the red and white wine gums. They must have evaporated most of the water to achieve a gum, or all of it to make a powder. This caught my eye because Leonardo writes of dissolving chalk with wine.

Leonardo – Lapis Amatita Macinata

August 3rd, 2014 § 1 comment § permalink

One of Leonardo’s most fascinating references to the word hematite comes in Institut de France Notebook A, fol. 104r, where he uses the phrase “lapis amatita macinata.” The context is an exercise for learning how to draw a site or place by looking through a piece of glass and representing the space beyond on the glass itself.

Below is a detail of Notebook A, fol. 104r.

lapis amatita macinata - Institut de France MS A, fol 104r

Leonardo – Detail of Institut de France Notebook A, fol. 104r – Reversed

It and Leonardo’s other notebooks may be viewed online, courtesy of the Biblioteca Comunale Leonardiana di Vinci. Here is a link to the Trattato (1651), where “lapis amatita macinata” has been shortened to lapis. Just following is Jean Paul Richter’s transcription and translation of the passage.



Have a piece of glass as large as a half sheet of royal folio paper
and set thus firmly in front of your eyes that is, between your eye
and the thing you want to draw; then place yourself at a distance of
2/3 of a braccia from the glass fixing your head with a machine in
such a way that you cannot move it at all. Then shut or entirely
cover one eye and with a brush or red chalk draw upon the glass that
which you see beyond it; then trace it on paper from the glass,
afterwards transfer it onto good paper, and paint it if you like,
carefully attending to the arial perspective.

“Red chalk” is how Richter translates the phrase “lapis amatita macinata,” but it is a bit more than that because of the word macinata. Macinata means ground, as in pulverized, and it’s something that people do. People grind. It’s not something that can be attributed to geologic events, to God, or to the passage of time. And if macinata refers to chalk, that would indicate that Leonardo is talking about fabricated, and not natural chalk. This is an important distinction because the general art historical thinking on red chalk is that artists began using natural red chalk in Italy in the late 15th century, and that it was only supplanted by fabricated red chalk in 18th century France.

Because both the Trattato and Richter’s transcription and translation of the passage in Notebook A, have omitted any reference to grinding, it has not received the attention it might have, except from Italian scholars. Carlo Pedretti, Piera G. Tordella, Angela Zanchetta, and Barbara Fanini have all zeroed in on the phrase.

Tordella’s excellent essay “La matita rossa nella pratica del disegno, considerzioni sulle sperimentazioni preliminari del medium attraverso le fonti antiche,” in Conservazione dei material archivistici e grafici (1996), where she goes quite far in advancing the idea of Renaissance period fabricated chalk, stops short of seeing the “lapis amatita macinata” reference as one to chalk, but prefers to see it as a  pigment applied with a brush in the glass exercise. I was a little surprised by this, but it is understandable if you look at folio 104r. Later in the essay she theorizes that Leonardo could have made chalk because of the phrase in question.

It’s worth looking at the phrase in a bit of detail, keeping in mind that lapis in Italian can mean either stone or chalk, there are two ways to read the words:

-ground hematite stone (mineral pigment)

-ground hematite chalk (fabricated chalk)

To have the image of folio 104r closer by, I’ll insert it again here.

lapis amatita macinata MS A FRANCE, fol 104r

Leonardo – Detail of Institut de France Notebook A, fol. 104r – Reversed

The one-letter word right after the cancelled word is not clear, and it really is the source of confusion. It could be either:

Italian  e   –  and  English
Italian  o   –  or   English

Again, these are the two possible ways to read the phrase:

…with a brush and with ground hematite stone…
…with a brush or with ground hematite chalk…

I believe Leonardo is writing about chalk, because I don’t see why the paint would have to be hematite since any color would be equally serviceable for this exercise. I also tend towards chalk because there’s some evidence, as Joseph Meder (p. 126) pointed out, that fabricators of stained glass had red chalk in their kits. (I’ll get to this in a later post.)

I can say one other thing, that if I had to follow the exercise, after putting my head in what amounts to a vise, with the benefit of only one eye, I’d rather the chalk option, than have to dip a brush into something that would probably be outside my field of vision. The paint choice would seem to be for a truly advanced practitioner.

Whatever the correct interpretation, after having read fol. 104r, I started looking for hematite chalk recipes and found some, albeit late ones from around 1800. I was just going to keep them as reference material, but I was encouraged to make my own chalk by Prof. Marco Tizzoni, an archeologist focusing on iron mining through the ages, who has recently retired from the University of Bergamo, of whom I’ll speak later. While I don’t think what I’ve fabricated so far is by any means brilliant, the chalk does link matita back to hematite.

Next – Hematite Chalk

Cennino Cennini and Hematite

July 24th, 2014 § Comments Off on Cennino Cennini and Hematite § permalink

Cennini was from the town of Colle di Val d’Elsa in Tuscany, and studied with the Florentine painter Agnolo Gaddi (active 1369, †1398). Cennini’s birth and death dates are unknown, but he married a woman from Citadella, north of Padua, and is documented as working in Padua in the closing years of the 14th century. His art treatise, the Libro dell’Arte is known through three early manuscripts, the earliest being in the Laurentian Library in Florence (Laurenziana, LCCVIII, codex 23), which is dated 1437. The work was first published in 1821 by Giuseppe Tambroni. Attempts have been made to attribute art works to Cennini, but nothing is secure.

This link leads to the Milanesi edition of the Libro dell’Arte, published in 1859 and available through Google Books. Pisa’s Scuola Superiore Normale also has the digitized Libro. The school, part of the Pisa University system, provides a website which has an excellent section on digitized art treatises. This link leads to the start page. Linking to individual books is not possible, as the links are unstable.

Cennini never discusses red chalk or crayon, but he speaks of hematite several times in his Libro dell’Arte. In chapters XV-XVII, he discusses how to make grounds for both parchment and paper, saying, among other things, how the support should be flattened, how the pigments must be well ground, and how to apply the tinting grounds with a soft brush. The chapters are very short; often just a few sentences long. Chapter XVIII discusses how to make a purple ground from hematite and lead white. He calls the color morella and gives an alternate color name, pagonazza. (Porpora, the more recognizable word for purple, appears twice in the Libro.)

Morella is a plant of the nightshade family, whose fruit or berry is a deep purple. It is also the name given to a blue-flowered plant, turnsole in English, which was used to produce a blue to purple dye. According to Treccani, the Italian encyclopedia and dictionary, pagonazza is a variant of paonazzo, as is pavonazza, and refers to a violet color in the peacock’s tail plumage. (I had a look at photos of peacocks and I didn’t see any feathers that looked particularly purple. Maybe the length, before the eye, is a dusty purple. I’ll have to remember to look for this when I next see a live peacock.) For a confirmation of the color purple, Filarete (1400-69) in his Trattato di Architettura, f.181v, says “azurro e rosso fa pagonazzo, o vuoi dire morello.” (Filarete’s treatise is online at SSN Pisa.) One can only imagine how many times pagonazza/o and morella/o were said together, up and down the peninsula, to convey the color.

To make this color purple, Cennini combines ½ ounce of lead white with a fava bean amount of hematite. (The fava bean measure shows he’s on the same wavelength as the cookbook writer, Julia Child, with her pea-sized dots of butter; along with Ada Boni and Elizabeth David, with their walnut measure. Or, at least, I can’t think of one without the others when I read these measures.) He uses two slightly different names for hematite, amatita and amatista, in the Libro. The a at the beginning may be a nice vestige of the Greek word. Ematite is the word used for hematite in current Italian.

Cennini says of the white lead and hematite, “grind them well, as much as you can; because grinding it a lot never hurts, but always enhances it.” In fact, grinding well and grinding long is the leitmotif of the Libro. Whether Cennini had a particularly purple hematite or whether his expert grinding turned the color from its usual red, is something that has to be left open.

Attributed to Fra Angelico - Last Supper - c. 1550 - Metalpoint, brush in brown ink, heightened with white, on red-violet prepared parchment - 77 x 59 mm - Stichting Museum Boijmans Van Beuningen 1940 (Koenigs Collection) - Inv. I 236 (PK)

Attributed to Fra Angelico – The Last Supper – c. 1450 – Metalpoint, brush and brown ink, heightened with white, on red-violet prepared parchment – 77 x 59 mm – Stichting Museum Boijmans Van Beuningen 1940 (Koenigs Collection) – Inv. I 236 (PK)

Just above is a drawing attributed to Fra Angelico, and is dated to c. 1450. It is at the Boijmans Van Beuningen museum in Rotterdam, and is one from a series of ten miniature drawings figuring the life of Christ, of which the Boijmans has seven (link to the seven here). It is on parchment, unlike most of the existing 15th century metalpoints, which are on paper. The cataloguer describes the color of the ground as red-violet. It’s probably more red than Cennini’s ground color, but it would be interesting to read if they’ve examined the color in the lab. Two of the drawings in the series, the Lamentation, and Christ Among the Doctors appear to be on a slightly different color of prepared parchment. Again, I haven’t read about this, but it could be a different batch of preparation than the other five, they could have been photographed on more than one day (!), or maybe they were subjected to more light. In any case, it is very hard for me to take my eyes off the images of these drawings. I now have three on my desktop.

Note of 25 July: The Boijmans drawing may well be pagonazza in color. Serpone & Company, a Naples firm specializing in religious vestments, sells a short cape for bishops, which is similar in color and which they call paonazza.

Other references to hematite in the Libro include the use of a smoothed piece of hematite to burnish gold, and as a pigment for painting. Hematite-rich materials such as bol and sinopia are also discussed, but not in relation to drawings on paper or parchment.

Ruling in Red Crayon/Chalk in Medieval Manuscripts

July 16th, 2014 § Comments Off on Ruling in Red Crayon/Chalk in Medieval Manuscripts § permalink

In my first post on red chalk, I wrote that red chalk was limited to marks made by readers in medieval manuscripts. Since then I’ve changed my ideas on this because of a medieval manuscript that passed through Sotheby’s London on 8 July 2014, lot 49. The manuscript is known as the Northumberland Bible, after its owners, the Dukes of Northumberland. According to the Sotheby’s cataloguer, it was probably made in the north of England, and dates to circa 1250-60. Just below is a detail of a pen-flourished initial and in the margins one can see the bounding lines in either red crayon or red chalk. It might well be crayon as the lines don’t seem to have budged. The folios aren’t numbered, but it’s the third from the last illustration or second illustration of an opening in the Sotheby’s entry. Sotheby’s includes other images from the bible with evident red crayon/chalk, but this seemed the clearest. There is no mention in the entry of bounding lines or ruling, but this is maybe their convention. (A brief look at other lots in the sale made no mention of ruling or the materials used for the lines.)

Sotheby's MS - Northumberland Bible - 8 july 2014 lot 49

Detail of folio from Northumberland Bible, English, c. 1250-60 – Sotheby’s London – 8 July 2014, lot 49

The British Library have a very useful illustrated glossaries section for the terms used to describe illuminated manuscripts. It’s based on a book by Michelle P. Brown, which was published jointly by the British Library and the Getty Museum in 1994. Links to the chalk and crayon entries may be accessed by clicking on the words. I’ve also pasted the entry definitions here:


Chiefly composed of calcium carbonate, chalk was used for a variety of purposes in manuscript production: as a POUNCE when preparing the PARCHMENT surface; as a component of GESSO or another GROUND; as a white PIGMENT; as an alkaline component in pigments (serving to modify the colour of certain organic pigments, such as folium, and to lighten and increase the opacity of others); or as a drawing medium.


A stick of white or coloured CHALK or other solidified PIGMENT, often brown or red in colour, sometimes contained in a holder, used for drawing, annotation, and occasionally for RULING.

Crayon, to me, implies more a fabricated medium than a natural one, but I love the term solidified pigment because it leaves the origin vague. I also think of crayon as more lustrous, and less friable, than chalk.

Red Chalk

June 22nd, 2014 § Comments Off on Red Chalk § permalink

Inevitably, talk of red chalk brings up the word blood. In Italian, the word for chalk is matita. It comes from hematite, a mineral and an ore of iron, that traces its name from the Greek word for blood, as in hematology. The French word sanguine, also used in English, comes from the Latin word for blood. Sanguigna is used in Italian, but less commonly than matita rossa. The iron that makes blood red, also makes red chalk red and maybe that’s why the endless testing of the Shroud of Turin never delivers an unequivocal answer. Whatever. Blood turns from anemone-red to a dark brown and the colors of red chalk fall in between.

Hematite is a medium-hard mineral. On the Mohs scale, which rates hardness by one mineral’s ability to scratch another, it comes in at 5-6. The scale is named after its inventor, an Austrian professor of mineralogy, Frederich Mohs (1773 – 1839). It’s a bit like the game of rock-paper-scissors, except that it makes sense and is useful, but it is also less fun. For reference, talc is 1 on the scale; and diamond, the hardest, rates a 10.

Hematite’s outward appearance is more often gray than red. Rock enthusiasts, if they’re in doubt about whether a rock is hematite, will test it by drawing a piece of the mineral across a streak plate, a piece of unglazed porcelain, and if it streaks red, it’s hematite. A piece of hematite, if used for drawing on paper, would do little else but gash the paper. However, it can also be flaky and almost soft. It naturally occurs with other minerals and when it does, it is considerably less hard than its usual 5-6  on the Mohs scale. Red ochre is the umbrella name for earthy pigments that contain hematite. Many of the different names for red ochre are listed in The Pigment Compendium, and include: carnagione [skin tone], sinopia, bol, among others. To this we could add, lapis rosso, which in its most literal sense means red rock. Lapis in modern usage means primarily pencil.

The image below is of a marble slab with the figures done in red ochre. It is usually titled the Knucklebone Players, referring to the girls in the foreground playing a game similar to jacks. Because of the inscriptions on the marble, which includes the name of the artist, Alexandros Athenaios, it’s known that the subject is Niobe pleading with Leto for forgiveness; something that Leto will not give. Niobe’s nervy boast (=hubris) about her having more children than Leto, dooms her children to death. It is from Herculaneum, that together with Pompeii and Stabia, provide the greatest window onto ancient painting. Vesuvius’s eruption created a perfect time capsule of the small cities (combined population of 15-20,000)–the planning, the buildings, the murals, sculpture, and arts of all kinds, as well as documenting the hell-like death of some inhabitants over the course of two days in the late summer of 79 CE.

Alexandros Athenaios - Knucklebone Players - Leto and Niobe

Alexandros Athenaios – Knucklebone Players [Leto Begged for Forgiveness by Niobe, with Three of Her Daughters] – 1st Century CE – Red ochre on marble – 490 x 420 mm – Museo Archeolgico Nazionale di Napoli – inv. 9526

The ancient Romans used the word rubrica for both red ochre and red chalk, and hence  rubrics. There are areas of the Knucklebone Players that look as if they could have been drawn with a pieces of red chalk, rather than painted in red ochre, but it would be very difficult to know for certain. In its present state it is remarkably similar to modern era drawings. There are also traces of pink, yellow, red and black pigment, but these are visible only with a microscope. The hematite-rich part is remarkably fresh, owing to its permanence, its being on the right support–a coarsely surfaced piece of marble–and because of its being buried for so many years. [One could look back further to the well-known prehistoric cave paintings in Spain and France for earlier use of red ochre; to its use in South Africa at the Blombos Cave near Capetown, dating back 100,000 years; and by early Neanderthals at Maastricht-Belvédère in the Netherlands, dating back 200-250,000 years.]

In the medieval period, red chalk was used for writing. Not in the production of the manuscripts themselves (where the red is generally from minium, cinnabar, and vermillion), but for the marginal ticks and notes added by readers. Bernhard Bischoff, who had catalogued thousands of ancient and medieval Latin manuscripts, wrote in his book on Latin palaeography, “Collations, marginal notes by readers, ‘nota’ signs and underlinings with a stylus or red chalk are found nearly everywhere.” Those who used red chalk probably did so because it would stand out from the ink text, making it easier to get back to the annotated section, immeasurably easier than retrieving notes made with a stylus. It might also have been seen as being handier than ink, being quick to pick up and set down, and allowed for reading away from a desk. It was also less permanent than ink and could be rubbed off parchment with pumice. It would be used in much the same way we would annotate in pencil. [Matita, in Italian, in addition to meaning chalk, also means pencil. In fact, if you asked an Italian child what was in their pencil case, they would reply, matite (pl),  referring, even if distantly, to the use of chalk as a writing implement more than to the chalk of drawings.]

The earliest drawing I can think of with red chalk is an anonymous Sienese double-sided drawing in the British Museum. They date it to the late 14th, early 15th century. The single biggest group of earlier 15th century drawings using red chalk is in the Louvre. The drawings are by Pisanello (c. 1395 – c. 1455) and his school. The sheet below shows how red chalk is used in the Louvre drawings–as a tint for the general coloring of the paper. The chalk is used in conjunction with pen and ink, but it is the ink part that is dominant. About a third of the 370-odd Pisanello and school drawings in the Louvre are on paper prepared with red chalk. They originally formed what’s called the red album, the pages of which were then incorporated into what’s known as the Codex Vallardi, after its 19th c. owner.  The red chalk is not limited to sheets with representations of people, but includes leaves with animals, architecture, and objects. It’s worth looking at these drawings to decide for oneself whether any of the chalk is used to model figures and objects. [Link to Louvre site.]

Pisanello - Legs - Plants - Louvre

Antonio Pisanello – Study of the Lower Legs of a Walking Man, Seen from Behind and Two Plant Studies – Black chalk underdrawing, pen and brown ink, brush and brown wash, white chalk heightening on paper irregularly tinted with red chalk wash – 249 x 176 mm – Louvre inv. 2264 recto


Leonardo Madrid II, f. 141v, f. 142r

Leonardo – Madrid II, f. 141v, f. 142r – Biblioteca Nacional de España

Leonardo (1452-1519) is credited with being the first to use red chalk by itself in a drawing. Its appeal came not only from the color, but also from the fact that very fine and precise lines could be made with a sharpened piece of red chalk. So precise that Leonardo used it for writing, and writing entire pages. Two folios from Madrid Codex II, show that his writing in red chalk comes close to his writing in pen and ink, in terms of fineness and clarity. 141v 142 r. Another opening in the codex shows drawings for the wire caging he would need for the projected, but never realized, casting of the monumental bronze Sforza Horse. The wire lacing, with all its intricacy, captivates in a way which you wouldn’t expect from an industrial or shop drawing–except in the hands of this master. The drawing also shows how red chalk can migrate. This is most clearly visible in the unintended ghost of the caging on the left page, made from the contact with the loose chalk dust of the drawing. It also shows why red chalk is so suitable for the transferral of designs, and for the making of counterproofs.

Leonardo - Studies for Casting of Sforza Horse - Madrid Codex II, f. 156v - f. 157r -

Leonardo – Studies for Casting of Sforza Horse – Madrid Codex II, f. 156v – f. 157r – Biblioteca Nacional de España

Leonardo used red chalk for representing many subjects. A name for red ochre is carnagione, or skin tone, showing its suitability for anatomical and figure studies in the related red chalk, of which he made many. He also used the material for all manner of machines, including armaments; geometric shapes; horses; maps; for mountains and storm clouds; for decorative knots; and also for unimaginably beautiful plant studies. The drawing below is of a branched bur-reed and it is very like the plant, in a way that Pisanello’s aren’t (they are generic plants, and while he shows interest in varying the leaf types, the flowers are identical on both plants). The detail of the Leonardo drawing below shows how he accentuated areas by using a brush and water. Where the brush and water traced the lines, the color is intensified, almost acting like an ink. (To see the greatest number of red chalks drawings by Leonardo in one place, it is worth visiting the UK Royal Collection.)

Leonardo Branced Bur-Reed Royal Collection Windsor

Leonardo – A Branched Bur-Reed – c. 1505-1510) – Red chalk, touched with wet brush, on pale red prepared paper – 201 x 143 mm – Royal Collection RC 912430 recto – Windsor

Leonardo - Detail of A Branched Bur-Reed - c. 1505-1510) - Red chalk, touched with wet brush, on pale red prepared paper - 201 x 143 mm - Royal Collection RC 912430 recto - Windsor

Leonardo – Detail of A Branched Bur-Reed – c. 1505-1510) – Red chalk, touched with wet brush, on pale red prepared paper – 201 x 143 mm – Royal Collection RC 912430 recto – Windsor

How Leonardo thought to use red chalk can only be guessed at. He may have quite spontaneously come up with the idea himself. It might have to do with his also being a fresco painter. Widespread appreciation for sinopia drawings came after the 1966 flood in Florence, when so many frescoes were removed from water-soaked walls, exposing the red ochre underdrawings, but the allure of sinopias must also have been felt by the artists themselves. He may have seen drawings by other artists, which are now lost. Another possibility is that artisans might have used red chalk, say in the transferal of designs where symmetry and repeats in patterns were important. Needlework, such as embroidery, comes to mind. It might also have to do with Leonardo’s father being a notaio. The Italian notai, literally notaries, are more like lawyers elsewhere. Their job is to draw up contracts and wills. If nothing else, Leonardo was born into a family where availability of paper and writing instruments was a given. Whether that included red chalk for making annotations and ticking the key points in long contracts, is something that I should look into. However, in my mind, it is increasingly likely that the first users of red chalk were the makers of stained glass windows and/or iron mine workers. I will write another post or two on why I believe this to be the case.

Other artists soon began using red chalk not only to tint paper, but also to draw with the material. First in Milan, among Leonardo’s students and later throughout Italy, helped by the adoption of the medium by Michelangelo, Raphael, and Correggio. The rapid spread is easily understood from the beautiful colors of red chalk.

Red chalk drawings have an animating affect on people. If you look at a group, for example a group following a museum docent around an exhibition, its members will show little signs of life in front of a red chalk drawing. They’ll straighten up or lean in at the drawing. Even at art history slide shows, red chalk drawings have the ability to lift people out of sleepiness like nothing else.

Next – Cennini, Leonado, Vasari, and Armenini on Hematite and Red Chalk

Note: There’s a video of an extremely interesting lecture by Sally Dormer on medieval Anglo-Saxon manuscripts and the drawings they contain. She illustrates a drawing which she believes has a red chalk underdrawing. Link here.