Paint seems simple; pigment suspended in a liquid medium. It has been around for millennia. When an early hominid picked up a lump of charcoal, or a chunk of ore, and discovered it would make a mark, our forebears began experimenting with embellishment. They collected, and later mined iron oxide, the mineral responsible for producing most naturally occurring pigments, and learned to grind it, mix it in liquid, and then smear, dab, spray, and brush colour onto surfaces. In Africa, Europe, India, and China, ancient artists used these ?earth colours? to create their basic palettes. The Minoans, Egyptians, Greeks, and Romans applied them mixed with water to a freshly plastered surface. As the plaster cured, the pigments seeped into it and a thin layer of calcium carbonate formed over the paint, sealing it against time, and preserving its colours. Around Vesuvius, a naturally occurring cement, ?terra di pozzuoli?, rich in iron and silicate can still be found. Some archaeologists believe it was responsible for the remarkable red walls found in some excavated Pompeian villas. When ?terra di pozzuoli? is applied as a final coat over pigmented lime, it creates a hard surface that sets quickly and adds a depth of rich red to the painted plaster beneath it.

Like great wines, the various ?terroirs? from which the ?earth colours? were excavated often gave them the names we still use to identify them. In classical antiquity, the preferred red ochre was called ?pontus euxinus? because it came from the city of Sinope, in Pontine. An inferior product came from Asia Minor, and to protect against imitation, ?pontus euxinus? was eventually processed into cakes of pigment that were sealed and stamped. Thanks to this early form of marketing, Pliny referred to the best red ochre as being ?sealed sinope?, and by the Middle Ages, the word ?sinopia?, had become a generic term for all red ochres.

At the beginning of the Renaissance, as paintings became an increasingly common art form, new pigment sources were exploited and a similar generalization of locale to colour occurred. The earth around Siena, rich with the iron ore limonite, produced the popular red ?sienna?; the twice-burned hematites of the volcanic area around Vesuvius, gave us ?Naples Red?, a lead antimonite from the same region created ?Naples Yellow?, and the ore around Verona, iron silicate in clay, gave us ?Verona Green?, also known as ?terra verte?. (Just to confuse things a bit, the best umbers came from Spain, rather than the province of Umbria in Northern Italy.)

Although painters had to rely on naturally occurring materials to create their pigments, not all came directly out of the ground. Many required processing, often with complicated and time-consuming procedures. As early as the fourth century BCE a recipe for a black known as ?elephantium? advised tightly packing scraps of ivory into a clay pot to exclude as much air as possible, then covering the pot with an iron lid and heating it in a kiln until a deep black pigment was obtained (a method still in use up to the 1920?s.) Burning animal bones, grape vines, or peach stones created other blacks. Exposing copper to acid and scraping off the powder resulting from the corrosion, made ?verdigris? or ?green of Greece?. (Guess where that method originated.)

Blues were more difficult, and expensive. Until the middle of the sixteenth century, almost all blue pigments in Europe were made from grinding semi-precious stones, such as lapis lazuli and azurite, and many artists, who could not afford to use them, chose to forego blue altogether. The invention of ?smalt? made blue more accessible. The process, first described by Borghini in 1584, used blue glass, which had been manufactured since antiquity. Although the blue colouring in glass was created with cobalt, only small amounts of the costly mineral were required, so it was not expensive to make. In the mid-sixteenth century, Christoph Shurer, a Bohemian glassmaker, began using moderately to coarsely ground blue glass as a pigment for paint. It worked well with water-based mediums such as tempera, (it was already widely used by Middle Eastern painters) however when suspended in oil, the colour was dulled, and the pigment was inclined to slip and streak.

In seventeenth century Europe, with the rise of the merchant class, oil painting continued to grow in popularity. Recipes for mediums, grounds, and glazes proliferated, and artists? preferences for pigments were recorded and debated. Although the earth colours were permanent, they were also muted, and the more brilliant pigments, mostly made from plants, were proving fugitive. Then, in 1704, a chemist, attempting to create a better crimson, discovered Prussian Blue. Precipitated from salt, potash, and blood, it was beautiful, permanent, and inexpensive to make. Its discovery marked the beginning of a new era in painting. Little more than a century after Prussian Blue was first created, artists were working with a palette that would have been unimaginable to an Old Master, but that story must wait for another article.

Contributed by Aubin van Berckel
aubin@opusframing.com