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Home2005 COLOR PIGMENTS: Article by Philips recipient


By Kandy Vermeer Phillips  

I became enamored with illumination after a trip to The Cloisters in New York City when I was thirteen. My study of medieval colors over the past year gave me a better understanding of what the medieval artist faced in order to produce the beautiful illuminations that I so admire. Not only did she have to deal with the vagaries of weather and crop failure, but also trade disruptions due to loss at sea, accidents, bandits, and the never-ending wars. By making my own paints I felt a bond with all the anonymous illuminators of the past, and a greater appreciation of the origins of artist’s colors. 

An important part of training for the medieval artist was to understand basic materials in inks and pigments: the secrets of making colors and how to use them in a painting, where to find the best earth colors, along with the practical issue of which apothecary sold the best mineral and lead-based pigments. The pigments that were used in an illumination were determined by what was available locally, through trade, and often by what was affordable. 

Ink was used to write the text of a book and to outline any decoration prior to its illumination. Inks were derived from three sources: carbon, iron gall, and plants. Iron gall ink is made from crushed oak galls mixed with iron salts and gum Arabic. Iron gall ink etches into parchment, and is more permanent. Iron gall was the most widely used ink in medieval times. It goes on as a thin, watery gray that quickly darkens into a rich black. After several hundred years, iron gall ink turns the familiar brown we associate with medieval texts. Carbon-based ink is made by collecting the residue of burning oil and kneading it with a binder into a stick form. A carbon-based ink would sit on the surface, allowing it to be easily removed; not a characteristic that a scribe would want when writing out an expensive book. Walnut ink is made from crushed black walnut hulls- the outer green hull and the inside nut- boiled in water with a rusty nail or iron salts and gum Arabic. Walnut ink was used primarily for drawing. 

Mineral colors formed the backbone of the medieval palette, either in their natural or manufactured state. Mineral colors consisted of natural earths, found locally or imported, gems such as lapis lazuli, malachite and azurite, and manufactured verdigris made from submerging a copper pipe into vinegar. In selecting a medieval palette of colors for my ASBA Grant Project, I focused on the least toxic materials. I took a course on Medieval Color, where we worked with arsenic-based orpiment, mercurybased vermilion, and the manufactured lead colors. This was in a properly controlled environment using small quantities of pigments. 

Earth-based colors are the easiest to use. Bags of dirt and clays are collected in the field. The dirt is cleaned through a process of washing the earth with water to separate the color from any unwanted impurities. Some earth colors may require grinding in order to smooth them out enough for painting. Medieval colors were not the finely ground pigments we have today. For example, when I ground malachite pieces into a pigment, the more I ground the pieces, the less color I had. I ended up with what appeared to be sand rather than the green I expected. Malachite, lapis, and azurite are ground very coarsely to preserve their color because they contain silica. Gum Arabic was the binder of choice mixed with water in a ratio of about 50/50 to the pigment. Some pigments required more binder, some required less. To test a pigment, a sample would be painted out and allowed to dry. If the color rubbed off, more binder was added; if it was too glossy, a bit less was used. Another binder was made from eggs. Egg white was whipped into a frothy meringue, and allowed to stand over night. In the morning the liquid, known as glair, was poured off and mixed with any mineral pigment. Egg yolk was mixed with water and reserved solely for vermilion, to warm the color. The mineral pigments are opaque. 

In addition to the mineral pigments, the medieval artist also had a palette of colors made from plants to work with. Plant-based pigments are an offshoot from the dye industry, and opened up a new world to the medieval painter. Plants were cooked down into a dye and used in that form as an inexpensive and not very permanent transparent wash. One of the most common examples was to wash rose madder over vermilion to give it warmth. This practice also increased the permanence of the rose madder, or any other plant-based color that was washed over an inorganic color base. 

To prepare organic colors soak the plant material overnight in distilled or spring water. The next day simmer the liquid and plant material over low heat to extract the dye, then strain. The resulting dye may be used to apply a simple wash of color onto a print or painting as we typically use watercolor. These colors are not lightfast as we understand the term, but have held up quite well in books. More complicated colors can be made by adding the liquid dye to chalk or white lead to make an opaque pigment. These pigments are dried and ground with a binder before use. Chemicals were also added to the dye to produce lake colors. A wide range of colors can be extracted by altering the PH of a dye bath. In a chemical reaction, the color is bound by chemicals – usually potash and alum – resulting in a stable pigment that is dried and stored for later use. These transparent pigments are known as ‘lakes’. The lake is the foam that collects at the top of the container. More pigment will settle at the bottom of the jar over a 24-hour period and this can also be collected and dried. 

Dye colors were stored in a variety of ways. Color could be stored in a lake form as a pigment, or the liquid plant dye was poured into shells to dry. When the water evaporated, a color concentrate was left behind similar to our pans of watercolor. Another popular method to store color was to make clothlets. Small pieces of cloth were dipped into the color and then dried, the process being done repeatedly until they were completely saturated. After the cloths were dried, they were sewn into little booklets, and stored away from dust and light. To use a clothlet, a piece would be placed into a shell with gum water; the color would leach out and be ready to use. 

The following plants were the most commonly used for color in medieval times. Dried Crocus sativus stigmas make a rich golden yellow color. It was an expensive color to use due to the intense labor needed to collect the stigmas. Saffron yellow was used as a substitute for gold and as an addition to vermilion or verdigris to warm and temper the colors. Reseda luteola, or weld, produces a clear yellow. The entire plant, fresh or dried is used. Weld is most often prepared as a lake pigment. Rhamnus sp., or buckthorn yields either a yellow from the unripe berries, or sap green made from the ripe berries. The ripe berries are mashed with water and allowed to ferment for a week. This mash is then cooked down to a paste. Sap green does not need a binder and was stored in pigs’ bladders, the original paint tube. Isatis tinctoris, or woad, was the blue color until indigo came on the scene. It is a noxious weed that ruins the soil through mineral depletion. The color is made from the leaves in a complicated process involving mashing wet leaves into balls and fermenting them in special woad drying houses. Indigofera sp. produces the familiar indigo blue. Blue dyes are very difficult to produce. Craftsmen who specialized in blue dyes were the elite of their trade. While indigo made a better blue color than woad, in Elizabethan England, the woad producers managed to get indigo’s cultivation banned under pain of death. Unscrupulous painters would substitute indigo for the more expensive azurite or lapis blue, even after the patron had specified and paid for one of these. Indigo was stored and sold in a solid form that was believed to be a stone. Caesalpinia is Brazilwood with a color range varying from red to orange to pink and purple by altering the PH of the dye bath while extracting the color. The color is found in the bark that is shaved into fine pieces and dust. Rubia tinctoria is rose madder. It is very difficult to get a true red from rose madder; usually the color comes out as an orange or brick red. The roots are dried, ground, and soaked in acidic water for up to a month to release the alizarin, then simmered over a low heat for an hour or more. The best color is extracted from roots that are three years old. 

Making pigments from scratch leads to a very thorough understanding of how the color is derived, and can lead to insights into how to combine colors. This was a lengthy but rewarding exploration into early pigment production. 

References- Daniel V. Thompson has written three very useful books that are Dover reprints: The Craftsman’s Handbook, ‘Il Libro dell Arte’, The Materials and Techniques of Medieval Painting, The Practice of Tempera Painting. 

All of the materials mentioned above are available from Kremer Pigments Inc., 228 Elizabeth Street, New York, NY 10012; or 

Editor’s Note: Kandy Phillips is a 2005 winner of a Silent Auction Artist’s Grant. This article is a summary of the year she spent studying illumination with that grant. 


Violet Illumination, 1.75x5.5,” Mineral colors on paper, ©Kandy Vermeer Phillips, 2006

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