The text below are excerpts from the book Bright Earth by Philip Ball
Van Gogh's portrait of Pere Tanguy who was his art dealer and colorman (via Colour by V. Finlay)
The connection to chemistry was perhaps deemed less distasteful in the nineteenth century, when chemists enjoyed unrivaled respectability (even Goethe used their metaphors). An anonymous writer on artistic technique in 1810 says cautiously: "Chemistry is to painting what anatomy is to drawing The artist should be acquainted with them but not bestow too much time on either." Yet even this much may be seen as a swan song to the era when the painter was of necessity something of a chemist, when a training in art required at least as great an attention to the mechanical and practical aspects as to the aesthetic and intellectual. By the end of the nineteenth century, the artist was wholly reliant on scientifically adept professionals—"colormen"—to attend to the chemical aspects of their profession. One consequence of this rift is that the colors of some works of that period he weathered less well than the jewel-like fifteenth-century paintings of Jan van Eyck.
Yves Klein invites us to engage with the beauty of raw color. This goes against our training. What is brightly colored? Children's toys, the Land of Oz. And so color threatens us with regression, with infantilism. Cultural theorist Julia Kristeva claims that "the chromatic experience constitutes a menace to the 'self' . . . Colour is the shattering of unity." What else is brightly colored? Vulgar things, vulgar people. Color speaks of heightened emotions, even linguistically, and of eroticism. Pliny is not alone in xenophobically attributing strong color to a kind of decadent orientalism Le Corbusier asserted that color was "suited to simple races, peasants. and savages." He found it in abundance in his "journey to the East and was repelled: "What shimmering silks, what fancy, glittering marbles, what opulent bronzes and golds . . . Let's have done with it . . . It is time to crusade for whitewash and Diogenes"13—which is to say, for cool reason over all this unseemly passion.
Wassily Kandinsky - Succession, April 1935
Kandinsky's fruitless search for the emotional language of color, like the tangles of color linguistics, reminds us that it is futile to be dogmatic about color. There can be no consensus about what colors "mean" or how to use them "truthfully." Color theories can assist the construction of good art, but they do not define it. In the end, the modern artist's struggle to find form for color is an individual quest. To Bridget Riley, it is precisely this that makes color so powerful a medium of artistic expression: "lust because there is no guiding principle, no firm conceptual basis on which a tradition of colour painting can be reliably founded, this means that each individual artistic sensibility has a chance to discover a unique means of expression."
The visible spectrum of light revealed through refraction
Scientists keen to celebrate Newton's reductionism, and artists eager to decry it overlook the strong mystical thread in his work—something that seems anomalous today, when the lens of centuries allows us to split science from magic. But it was quite in keeping with the spirit of his age that Newton saw fit to identify an arbitrary seven subdivisions of the prismatic spectrum purely to establish consonance with ideas about musical harmony: "Do not several sorts of rays make vibrations of several bignesses, which according to their brightness excite sensations of several colours, much after the manner that the vibrations of air, according to several bignesses excite sensations of several sounds?"' And so the Newtonian rainbow acquired its indigo and violet where I defy anyone to see other than a blue deepening to purple.
Color comes from plucking this rainbow. Newton's analogy with music is misguided in any concrete sense but useful as a metaphor. Matter sings to many different notes and chords in the chromatic scale. When the resonances are sounded in the glare of the white "noise" that is sunlight, these notes are absorbed from the multipitched stimulus and fall silent in the echo. What we see as color is the remains, after the material has absorbed its own private and unique chime. A red berry sines to the tune of green and blue, a yellow flower to the strains of blue and red.
Wenceslas Hollar - The basilisk and the weasel
Art conservator Spike Bucklow has suggested that some of the other pigment recipes recorded by Theophilus and Cennino can also be interpreted in terms of alchemical theory. Theophilus tells how to make a color called Spanish gold (the name immediately speaks of a Moorish, and hence alchemical, origin). Among the sound practical advice in his manual, Theophilus' prescription here seems to suffer an outbreak of pure magical thinking: "There is also a gold named Spanish gold, which is compounded from red copper, basilisk powder, human blood, and vinegar. The heathen, whose skill in this art is commendable, create basilisks for themselves in this way." He goes on to explain how these fabulous creatures emerge from hen's eggs hatched by toads fed on bread. "When the eggs are hatched, male chickens emerge just like chickens born of hens, and after seven days serpent tails grow on them." The blood, meanwhile, must come from a red-haired man and must be dried and ground. Of course. there is nothing particularly outlandish in a twelfth-century belief in basilisks, but Bucklow suggests that this can be seen as an allegory for the preparation of an alchemical elixir from a red "sulfur" (the blood) and a white 'mercury" (the basilisk ash). Certainly, the reference to the pigment as "a cold" suggests that the author saw no reason to distinguish it from the metal itself.
Annunciation by Simone Martini, 1333
The one color the alchemists could not conjure up for painters was the one they labored the hardest to devise. Struck by slanting rays of the sun, gold set the medieval altarpiece ablaze with light. In Byzantine churches like the sixth-century San Vitale in Ravenna, golden mosaic tiles create a dome shimmering with holy radiance. Whatever the cost of ultramarine or vermilion, gold has ancient associations that make its value transcendental.
The use of gold in medieval art shows us more clearly than am-thing else how the nature of materials took precedence over any concern for realism. Until at least the fourteenth century, holy figures on altar panels are framed not by nature's skies or foliage, not by draperies or masonry, but by a golden field that permits neither depth nor shadow.
In later ages this metallic sheen was pushed back onto the gilded frame that held the canvas, but for the medieval artist gold was a color in its own right. It was applied to the gessoed panels in the form of thin sheets: gold leaf. There was no need to visit the apothecary to procure this color, for it was to be found in the purse of every wealthy person. The craftsmen of the Middle Ages, unrestricted by laws protecting currency, made their cold leaf by hammering and hammering at golden coins, transforming them to sheets so thin as to feel almost weightless.