What is your favourite colour?
Aureolian, carmine, orpiment, hematite
or a phthalocyanine blue?
by Cheryle Harrison
Conservator, Pacific Conservators
PIGMENTS have an ancient history and their sources and fabrication methods range from the simplistic to complicated alchemic concoctions. Many of these pigment colours are rarely known today, while others continue in use.
Some early pigments have been found on the walls of caves with images of animals, geometric designs, figures, and handprints. Narratives of hunts and daubed depictions were made using a bone or fingers. Burnt cinders were utilized for black. Colours in red and ochre tones were made from earth clays mixed with animal fat or blood. These simple images were succeeded by Egyptian hieroglyphics and Faiyum portraiture. Wax intermixed with pigment, and ground colours blended with water or spirits of wine are colours dating as early as 2300 B.C. A deeply purple colour, Egyptian blue, was produced by boiling mussel shells. Examples of Egyptian artwork remain visually brilliant and exist to this date.
Old manuscripts and early histories illustrate sources and recipes for pigments that read like myths. The unusual makes for romantic reading and recreates colours in words. Plants, minerals, and insects were ground, floated, burnt, or precipitated. Poetic names and conjuring processes are represented by these 17th century pigments: Woad or Istatis Tintoria, with its third name, Florey was an organic blue pigment made from the dried froth extricated from a boiling plant dye. A more alchemic sounding, Purple Precipitate of Casicous or Gold Purple was made by dissolving powdered gold and tin filings in a mixture of nitrate and hydrochloric acid.
How pigments are ground and prepared affect the durability and brilliance of colours. Smalt, a favoured 17th century pigment linked to an Egyptian paint, was glass silica ground for a soft blue colour. To overly grind the glass particles would offer up a lackluster paint, as the pigment would be ground to invisibility.
Many earlier pigments were later proven to be unstable. They would fade, degrade, or chemically change when mixed with other pigments or materials. For instance, Naples yellow when mixed with earth colours can turn black. Copper resinate pigments, so popular through the 15th to the 19th centuries are fugitive greens that recurrently turned dark brown due to its own decomposition. Conversely, the Paleolithic colours of ochre and black remain for use as materials in modern paints.
As the history of art has developed, so have changes occurred in the sources, manufacture, and use of pigments and paint. Pigment used for artwork evolves from encaustic, tempera, oil, watercolour, to later manufactured acrylics, alkyds, water-soluble oil paints, and industrial paints. Adulterants and additives are employed to thicken, thin, quicken or inhibit the innate characteristics of paints. Pigments when made into into paint can have a durability in one type of medium, and be deleterious when in a different medium. An interest in pigments can span many points, including, toxicity, slow and fast drying characteristics, and the physics of aging.
The boundaries of expression and availability of materials today are vast. Alchemy and the artists' personal knowledge of pigmented colours have yielded to technologically derived colours commercially available in tubes and plastic containers. Generally speaking, today's artist embraces the benefits of chemistry and convenience.