Primary Colors - Pigment Selection
3 April 2011
Our broad introduction to color theory explored how red, yellow, and blue prevailed as the foundation of the artist’s paint palette. Here we will discuss the practical challenge artists have faced to interpret these basic colors using pigments. We will see how external factors such as geography, trade, and technology affected the selection of these fundamental materials. The history of each individual pigment is vast and captivating! While it is not possible to give each its due here, further reading from the references below as well as the product pages of our online catalogue is strongly encouraged.
In the 12th century, northern European paintings were made with pigments suitable for water-based media, as tempera painting was the standard. Theophilus does mention oil-based painting in his 1125 treatise On Divers Arts, but historians speculate that this refers to the painting of sculpture and other objects requiring a more durable paint film in outdoor use. Studio records of this time describe the use of lapis lazuli for blues and orpiment (from the Latin aurum, meaning “gold” – actually an arsenic sulphide) for yellow. Red lead (minium) was used for yellowish reds, and vermilion (mercuric sulphide, called Cinnabar in its natural state) for bright reds.
In the 13th century, the increasing popularity of oil mediums brought changes both to painting technique and to the pigments artists favored. In addition to producing a more flexible paint film, the higher refractive index of drying oils rendered many pigments transparent where they would not be in tempera 1. Oils were also more acidic, and so its effect on pigments was newly considered.
Azurite, a native mineral to Northern Europe, had been used by the Egyptians but now gained more widespread use as a primary blue pigment. This was possibly due to scarcity and rise in the cost of Lapis, which was imported primarily from Afganistan through a primary trade post in Venice. Azurite is a natural basic copper carbonate, and like many copper pigments, can turn greenish and darken in oil. It’s use in oil painting was made possible by a special preparation in egg protein which protected the individual particles from the acidic oil. Lapis was still used, though until a system for its purification into natural ultramarine was developed 2, it was not used in glair 3, oil or resin glazes.
Orpiment remained in used for opaque yellow tones, while translucent yellows were made using raw sienna. Vermilion and red lead continued to be used for opaque reds, but the desire to create glazes in oil demanded transparent colors. This led to experimentation with organic reds.
As the 14th century progressed, the readily available colorants described in historical trade documents were those that could be used as dyes or for medicinal purposes. Transparent colorants such as brazilwood and lacca (lac) are mentioned, as well as realgar, an arsenic-based yellow, and indigo. Brazilwood and Indigo could be used as dyes, and realgar was unfortunately used to cauterize wounds and remove hair! Thank goodness for Cennini’s early warnings to painters of the toxicity of arsenic compounds!
Records from France in the 15th century continue to laud azurite and natural ultramarine for their brilliant blues. Vermilion and red lead continue to be used, though red lakes (organic red dyes precipitated onto white or transparent minerals) begin to be used for the glazing techniques afforded by oil. By the 16th century madder was cultivated on a large scale in Europe. In 15-16th century Southern Europe (the heyday of book illumination) the term “Paris red” referred either to a costly pigment made from lac or a to cheaper product made from brazilwood and alum. For blue, “Azur” usually signified azurite, but also sometimes lapis, indigo, or any synthetic copper-containing blue pigment. Orpiment had not yet been replaced, though lead-tin yellow pigments were newly utilized, and ochers and other earth pigments were employed for yellows.
In the 16th and 17th centuries, a few new blue pigments were described in trade documents from Germany. Smalt, the first pigment manufactured from cobalt, became very popular in Northern Europe and Spain. It was also used by paper makers and marblers to counteract the yellow of paper, and by launderers as a washing blue. A synthetic version of azurite became available, called blue verditer, and Indian indigo again increased in popularity, after being for a time replaced by the more affordable woad, a European source for the indigo dyestuff.
In the early 18th century, Prussian blue was synthesized when a German chemist mixed some cochineal with iron sulfate and cyanide – the first of the “modern” colors. Considered a chemical at first and not a pigment, it could be manufactured without regulation by painters’ guilds, leading to faster widespread use. Though not considered a primary blue, like indigo it was used as such due to its economy over other mineral blues.
August-Ludewig Pfannenschmid, a colorman who worked in or near Hanover in the later eighteenth century, chose carmine 4, gamboge 5, and the traditional ultramarine as the ideal primaries. This history of carmine is particularly interesting and fraught with international affairs 4 …
It becomes more challenging to distinguish between colors and pigments when interpreting 19th century sources on the subject of paint composition. Undocumented substitutions for pigments were frequent. Naples yellow, for example, could be composed of admixtures of cadmium yellow and white, (which could be either lead or zinc). Lemon yellow could be chromate of barium, strontium or zinc. These chemical discrepancies might be lost on the artist, but he would definitely notice the inconsistencies of his paint! Adulterants, not an unfamiliar problem in trade, were widely noted in madder reds and vermilion (with cochineal added to provide bulk) and cobalt yellow, mixed with or supplanted by cadmium or chrome.
The development in the late 19th century of coal tar colors would have a major influence over a painter’s palette in subsequent decades, though at the time few saw their value as artists’ colors. These colors are usually bright and transparent, and new formulations of the coal tar colors have greatly improved their performance in recent years. We suggest the following pigments for demonstrating three-color processes and mixing the common color wheels to explain color theory and physics of light: Permanent Red B 23290, Permanent Yellow 23310, and Phthalo Blue 23050.
Whew – such a long post and yet we barely scratched the surface!
Footnotes:
1. Green earth, for example, had been invaluable as a semi-opaque base for flesh tones in tempera yet loses its color when mixed with oil. Other darker pigments such as carbon blacks and deep earths were too dense in egg medium to be used outside of outlining but were rediscovered in oil as transparent shadows and glazes.
2. First recorded by Marco Polo in 1271 and detailed by Cennini a century later.
3. Glair is a sizing or paint medium made only from egg white (principally albumen). A paint film bound with the white will dry to a harder, more brittle finish as it contains less egg fat to plasticize the paint film. It has the advantage, however, of remaining without color.
4. Carmine is a lake pigment made by extracting carminic acid from the scale insect cochineal, imported from South America in dried form only (export of live insects was apparently prohibited to preserve a monopoly in cochineal – read more in the book by Harley)
5. Gamboge is a gum resin from varieties of evergreen trees which grow in south east Asia (The name is derived from Camboja, the archaic name for Cambodia where the trees are found). It is a golden transparent yellow most often used in watercolor, as it needed no additional binder.
Sources and suggested reading
R. D. Harley, Artists’ Pigments c. 1600–1835: A Study in Documentary Sources, 2d ed. (London, 1982)
(BOHARLEY)
Leslie Carlyle, The Artist’s Assistant: Oil Painting Instruction Manuals and Handbooks in Britain, 1800–1900, with Reference to Selected Eighteenth-Century Sources (London, 2001)
(BOCARLYLE)
Jo Kirby, Susie Nash, Joanna Cannon (Ed.), Trade in Artists’ Materials: Markets and Commerce in Europe to 1700. Archetype Publications Ltd, London (28 Feb 2010)
(BOKIRBY-TRADE)
“The Materials and Techniques of Painting” by Kurt Wehlte. Kremer. 1975.
(BOWEHLTE REPRINT)
Web (re)sources:
Pigments Through The Ages: http://www.webexhibits.org/pigments/
Oil painting – Century, Painters, Paintings, and Drying: http://arts.jrank.org/pages/9753/Oil-painting.html#ixzz1JEKxR7UF
Thirty Six Shades of Prussian Blue by Joshua Cohen:
http://canopycanopycanopy.com/8/thirty_six_shades_of_prussian_blue
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