Understanding Pigments

Q. What are pigments? Where does the manufacturer get the dry pigment powders they use to roll into a paste form for oil paints? Are they produced by a chemist in the lab or are they natural organic and inorganic products?

A. Pigments are particles of colored materials that are insoluble in water, oil and resin. When suspended in liquid binders or vehicles, the pigment forms paint. The binder or total vehicle used with each pigment, as well as the size and shape of the pigment particles, determines the type of paint that’s created.

It’s also important for you to know that there isn’t one answer for where laboratories get their dry pigments. There are actually three basic types of pigments that a manufacturer may use when creating paint: natural organic pigments, synthetic organic pigments and inorganic pigments.

Natural organic pigments are those made from carbon compounds that occur in nature. In prehistoric times, early humans found many natural organic colorants in the minerals occurring in soils and clays. Cave paintings using red- and yellow-colored clays date from at least 15,000 B.C. As long ago as 8,000 B.C., artists in Egypt had discovered how to process animal products and vegetable matter into useful and fairly stable colorants.

Synthetic organic colorants are also made from carbon compounds, but these kinds of compounds had to be created in a laboratory in order for the pigment to exist. The last quarter of the 19th century and the first quarter of the 20th century saw tremendous improvement in the color range and durability of processed mineral and synthetic pigments—synthesized copies of the hues found in animal- and vegetable-derived organic colorants, made in laboratories under controlled conditions. The production of the phthalocyanine colors, very stable and powerful colorants, led to a renewed interest in synthetic organic pigments. Today, the synthetic organics make up the largest share of colorants used in the industry and are extensively tested for use in many artists’ paint lines.

Inorganic colorants are those made from pigments that aren’t carbon-based, and many of them don’t occur naturally. Inorganic colorants are broken down into three more categories: earth pigments, mineral pigments and synthetic pigments. White lead, a precipitated lead carbonate, is probably the best known early artificial pigment that’s still in demand and in wide use today. Iron oxides were mined extensively in Italy and processed by heating, levigating (water washing) and other mechanical means into a range of red, yellow, green and red-purple hues that are still some of the most useful colorants artists have.

Maggie Price is a pastel artist, writer and workshop instructor living in Rio Rancho, New Mexico. See her work at www.maggiepriceart.com.

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