A rainbow in constant flux

Painters must contend with the evolving chemistry of pigments

March 14, 2002

There is, today, an unfortunate dissociation between painters and scientists. In "Bright Earth," Philip Ball argues that this was not always the case by tracing the history of pigments and their relation to art. Artists at one time were virtually chemists - or at least alchemists. They knew their materials. As his story develops, we hear about specific chemists and their discoveries, as well as specific artists and their use of these discoveries.

Colors available to painters in the past came and went. They were not always discovered and made primarily with artists in mind. Dyes for cloth often took precedence, for example. Sometimes colors were just a serendipitous byproduct of unrelated chemical investigations. For ages, artists longed for better blues or greens (and yellows and reds - all colors, in fact), but had to make do with the few at their disposal.

Cost was frequently involved. It was a rich patron who could insist on ultramarine. This always costly blue was at one time more expensive than gold. Its rarity value informed its artistic value. Once a far cheaper synthetic ultramarine came onto the market, artists came to relish the color less. Besides, the superseding of organic pigments by synthetic pigments brought, among many other available hues, a whole range of new blues that meant ultramarine became just one among many.

Things have, of course, changed over the centuries. Ball offers a telling statistic to show how much more vast the range of colors available today has become: "Tyrian purple, the imperial color of Rome, was drawn out of shellfish. Blue indigo was the frothy extract of a weed. Madder red came from a root, cochineal from an insect. Today virtually all dyes are synthetic organic molecules, their carbon skeletons custom-built by industrial chemists. While barely a dozen natural dyestuffs proved stable enough to be useful in the ancient and medieval world, more than four thousand synthetic dyes now bring color to our industrialized societies."

Colors, or available pigments, have not always been completely reliable. At times, immediate profit took precedence over any guarantee of the long-term preservation of pictures. Even more recent paintings show the effects of chemical instability.

Ball describes how some works by certain 19th- and 20th-century artists - Van Gogh, for example, and Rothko - have altered or degenerated radically from their original color intention because of an ill-informed or careless knowledge of pigments. Ill-informed because we have become increasingly dependent on color manufacturers and suppliers. Careless because of a modern sense of urgency or an actual indifference to posterity.

Given the largely intuitive procedures of artists, Ball sensibly does not endeavor to press them to spend more time ascertaining the permanence of their pigments. He is realistic enough to know that this is probably a lost cause. And he points out anyway that all paintings, however scrupulous their painters were, inevitably undergo change. One is never looking at a painting as it was when freshly made.

Ball even discusses the misleading nature of reproduction as a way of assessing pictures, whether mezzotint, lithograph, photograph, or digital image. All reproductive methods to this day, are, in printed form, dependent on available pigments and on our understanding of color mixing.

This is a fascinating book. Ball writes with authority about both sides of the equation, as apparently familiar with chemists as with artists. His view of art history is sometimes unconventionally enlightening because of this viewpoint (though sometimes he also betrays unfair prejudices; his dislike of Constable is one).

He believes, with Dubuffet, that "there is no such thing as color, only colored materials," and that art at any given period is bound to be limited or expanded by the availability of pigments. But he also discusses color theories at length. He shows, for example, how confusion about the difference between mixing color as light and color as pigment has sometimes misled both artists and theorists. He talks about a suspicion artists over the ages have had about mixing pure colors. They knew in practice, if not always in theory, that mixing primary pigments reduces brightness. This, Ball explains, is because mixing pigments is a "subtractive" process, while mixing color as light is additive, increasing brightness.

He has himself a quite evident preference for pure bright color, and this shows itself in a much stronger appreciation for Titian and Veronese than for Van Dyck or even Rembrandt. He rates Turner way above Constable for similar reasons. And yet what he is inclined to dismiss as muddiness has been the very powerful language of some artists. The be-all and end-all of painting is not necessarily Fauvism, Sonia Delaunay, or American color-field painting, however splendid.

Brilliant pigments are a magnificent, stimulating tool for painters, like brightly flowering plants for gardeners. But some gardeners make magic with nothing more than the close-toned, subtle greens of foliage and the browns and grays of sand, gravel, and earth.

• Christopher Andreae writes for the Monitor from Glasgow, Scotland.