These chemical colors appear because they absorb some of the white light and reflect the rest. So the green glass on the book cover is simply absorbing the red and orange wavelengths from the white light around it, and is rejecting the green—so that is what we “see.” But the big question is why? Why should some substances absorb red light and some absorb blue? And why should others— “white” ones—not absorb very much light at all?
If you are, like me, not a scientist, you’re probably inclined to skip this section, but stay with me because it is quite an astonishing story. What is important to remember about “chemical” coloring is that the light actually does affect the object. When light shines on a leaf, or a daub of paint, or a lump of butter, it actually causes it to rearrange its electrons, in a process called “transition.” There the electrons are, floating quietly in clouds within their atoms, and suddenly a ray of light shines on them. Imagine a soprano singing a high C and shattering a wineglass, because she catches its natural vibration. Something similar happens with the electrons, if a portion of the light happens to catch their natural vibration. It shoots them to another energy level and that relevant bit of light, that glass-shattering “note,” is used up and absorbed. The rest is reflected out, and our brains read it as “color.”
For some reason it is easier to understand this idea of electromagnetic waves actually altering what they touch when you are talking about invisible ones like X rays. It is hard to believe that light—lovely friendly white light—also changes almost every object it hits, and not only the ones that contain chlorophyll which are waiting for the right wavebands of light to make them photosynthesize.
The best way I’ve found of understanding this is to think not so much of something “being” a color but of it “doing” a color. The atoms in a ripe tomato are busy shivering—or dancing or singing; the metaphors can be as joyful as the colors they describe—in such a way that when white light falls on them they absorb most of the blue and yellow light and they reject the red—meaning paradoxically that the “red” tomato is actually one that contains every wavelength except red. A week before, those atoms would have been doing a slightly different dance—absorbing the red light and rejecting the rest, to give the appearance of a green tomato instead.
I saw what I understand to be transitional color only once, on a journey to Thailand to undertake a ten-day fast. I was feeling good (although I had never realized it is possible to smell chocolate ice cream at 20 meters), and on day nine I was walking through a garden when suddenly I stopped in amazement. In front of me was a bougainvillea bush covered in pink flowers. Only they were not pink, they were shimmering—almost as if a heartbeat had been transformed into something visible. I suddenly understood with my eyes and not just my mind how the phenomenon of color is about vibrations and the emission of energy. I must have stood there for five minutes, before I was distracted by a sound. When I looked back the bougainvillea had returned to being flowers, and nature had turned itself the right way round once more: it’s usually easier that way. After I started eating, this never happened again.
There are several “physical” causes of color,3 but one with which we are all familiar is the rainbow, which forms in the sky when light bounces around raindrops and gets divided—what is called “refracted”—into its separate wavelengths. This explanation was famously discovered in 1666 by a young man sitting in a dark room with two small pyramids, or prisms, made of glass in front of him. In the window shutter he had drilled a small hole, about a centimeter wide, which allowed a thin beam of sunlight to shine into the room. On a day that has become myth, the Cambridge student— whose name was Isaac Newton—held up the prism and saw how it made what he later described as a “colored image of the sun” on the opposite wall. He already knew that this would happen, but his genius lay in placing the second prism upside down so the multicolored light passed through it. And he found that this time the rainbow disappeared and white light was restored. It was the first time a scientist had acknowledged that white light was made up of rays of every color in the spectrum, and when Newton finally published his findings—it took him thirty-eight years4—it was the first real explanation of how the ray of each color bends at a certain fixed angle while passing through the prism. Red bends least, and violet bends most. And in the same book Newton named five other colors that lie between the two of them. One of his choices was extraordinary, as I would find out in my search for indigo.
The Proof by Experiments.
Exper.3. IN a very dark Chamber at a round hole about one third part of an Inch broad made in the Shut of a Window I placed a Glafs Prifm, whereby the beam of the Sun’s Light which came in at that hole might be refracted upwards toward the oppofite Wall of the Chamber, and there form a coloured Image of the Sun.
Preface for early edition of Newton’s Opticks
Years later the Romantic poet John Keats would complain that on that fateful day Newton had “destroyed all the poetry of the rainbow by reducing it to prismatic colors.” But color—like sound and scent—is just an invention of the human mind responding to waves and particles that are moving in particular patterns through the universe—and poets should not thank nature but themselves for the beauty and the rainbows they see around them.
While I was writing this book I went to a party one evening and a fellow guest looked at me sternly. “You have to have one character running through your book. That’s how all those new nonfiction books work,” he said firmly. “Who’s your character?” But, as I hesitantly admitted, I didn’t have one. Later I realized I don’t have one character, I have many. Just as a prism shows us a multiple of different wavelengths—which our brains call colors—so each color has produced a spectrum of personalities. They are all people who through the ages have become fascinated by color. There’s Thierry de Menonville, the arrogant French botanist, Isaac Newton in his dark chamber naming the rainbow, Santiago de la Cruz eking out a living embroidering shirts in the Mexican hills, dreaming of purple, Eliza Lucas foiling evil plans to prevent her making commercial indigo in Carolina, Geoffrey Bardon, whose generosity and poster paints allowed some equally generous Aboriginal men to create an art movement that would change lives. Few of these people ever encountered each other, even in books, but I’ve enjoyed meeting them all on my journeys, and I hope you do too.
INTRODUCTION
The Paintbox
“In old days the secrets were the artist’s; now he is the first to be kept in ignorance of what he is using.”
WILLIAM HOLMAN HUNT, in an address to the
London Society of Arts
“What did I learn at art school? I learned that art is painting, not painted.”
HARVEY FIERSTEIN, quoted in the exhibition “A Family Album:
Brooklyn Collects” at Brooklyn Museum of Art, April 2001
The prison was called “the stinker,” and it was the place where debtors tended to disappear for years. This medieval Florentine institution would have lived up to its name particularly in summer, and it was on one such rank and smelly day in the mid-fifteenth century that a man sat at a wooden desk. To his left was a pile of handwritten papers, and to his right was one final page. Perhaps he paused for a moment before doing something that was probably forbidden to him as a prisoner of the Vatican: picking up his quill and marking the date—July 31, 1437—and the words “ex Stincharum, ecc.” The postscript not only notified readers that the document was written in the heart of the Stinche itself, but it also puzzled scholars for years.
The book was Il Libro dell’Arte by Cennino d’Andrea Cennini, and it was to become one of the most influential painting manuals written in the late medieval period—although it would take more than four centuries to find a publisher. It was not the first “how to” book of paint-making: there had been a few in the past, including the Mappae Clavicula from the ninth century which included a veritable hodgepodge of recipes for pigments and inks for illuminated manuscripts, and in the twelfth century the mysteri
ous metalworking monk Theophilus wrote his De Arte Diversibus describing how to make stained glass and metalwork as well as paintings. But Cennino’s book was special. He was an artist, the direct inheritor of a tradition1 that stretched back to Giotto di Bondone in the late thirteenth century, and his Handbook was the first time a professional artist had revealed the secrets of his trade so comprehensively and openly. And when in the early nineteenth century the book was taken down from its shelf in the Vatican library, dusted off and published,2 it was to cause a minor sensation in a European art world that was beginning to realize that in so single-mindedly pursuing its art it had neglected to remember enough of its craft.
At first, having read the “Stinche” postscript, art historians imagined that the manual—later translated into English as The Craftsman’s Handbook—was written by a criminal. They fondly pictured Cennino as an old man writing his memoirs in a miserable lockup, so caught up by the beauty of the processes he was describing that he omitted to mention the ugliness of his present location. Just as Marco Polo only spoke of his travels into the heart of Asia many years later, when he had time on his hands and a willing scribe in his prison cell, so, people thought, his Tuscan compatriot only wrote about the mechanics of painting the shadows once he was locked firmly inside them. Sadly for the imagination, although rather happily for Cennino, later researchers found other copies of the manuscript without reference to any penitentiary. They had to concede reluctantly, that Cennino probably lived and died a free man, and that the version with the postscript was written by a literate prisoner who was condemned to copying books for the Pope.3
Whenever I open Cennino’s book—and he has acted as my “guide” for many of the journeys in this book—I often think about that copyist. What kind of man would he have been? An educated one certainly: something of a scoundrel perhaps—in prison for debt, or for a white-collar (or black medieval velvet-collar) crime. He may have been in there for years, copying out pious prayers and religious treatises in neat longhand. And then suddenly, somewhere between a prayer book and a Bible, the prison librarian handed him his next project: a treatise containing the kind of valuable secrets that a man would never have dreamed would fall into his hands—at least not while he was doing prison labor.
As he began writing, our scribe may have felt a kinship with those whom Cennino chides for having chosen their artistic careers “for profit”—as well as a distant curiosity about those others who had entered the profession “through a sense of enthusiasm and exaltation.” And then a few pages later he may have felt a sense of exaltation himself. If he knew anything of the art world he would be aware of how secretive artists were about the tricks of their trade, and how in order to learn them apprentices lived in the studios of their masters for years, grinding pigments, preparing canvases, and then, after many years, being allowed to paint backgrounds and less important figures. It was usually only when they themselves became masters that they could stroll into their own studios to finish the faces and main figures on canvases their own apprentices had prepared earlier.
Here are some of the many things Cennino explains in his book: how to make imitations of expensive blue using cheaper pigments; how to use tracing paper (by scraping kidskin until “it barely holds together,” then smearing it with linseed oil) to copy a master drawing; which types of panel were favored by thirteenth- and fourteenth-century masters (fig wood was good) and how to paste old parchments together. Cennino claimed, probably sincerely, that his Handbook was intended for the good of artists everywhere, but if there had ever been a Teach Yourself Medieval Art Forgery guide, this was it. And our man in the jail had the document.
We cannot know whether our copyist ever managed to take advantage of his knowledge. I like to think so. I imagine him leaving the prison at the end of his term, and going into the equivalent of the antique business, touching up century-old panels with a judicious spot of gilded tin carefully prepared in the way that Cennino recommended, or mixing glues made of lime and cheese, just as Giotto might have used to fix his own painting boards.
But whether he capitalized on it or not there must have been days when our incarcerated scribe would have fantasized about cooking up green with good wine vinegar, or designing cloths of gold. No doubt he would have thought wistfully about being free to sit in chapels, sketching with the thigh bone of a gelded lamb and making sure the light was falling on his left side, so his drawing hand did not make a shadow across the paper. And he would certainly have paused for some kind of thought as he read Cennino’s warning against something that can make your hand so unsteady “that it will waver more, and flutter far more, than leaves do in the wind, and this is indulging too much in the company of women.”
The book has certainly inspired latter-day forgers. Eric Hebborn was one of Britain’s best-known twentieth-century forgers, who became something of a celebrity. He wrote several books, but his last one, The Art Forger’s Handbook, explicitly set out to teach the amateur how to make decent fakes in the kitchen. He used and adapted Cennino’s advice extensively—preparing panels, tinting papers different colors, and making brand-new works look as if they had been varnished some time before (by using beaten egg-white, left overnight and then painted on with a brush), just as the master advised.
But as well as forgery, in the years since it was rediscovered, Cennino’s book (along with other early manuals of how to make paints and dyes) has inspired something rather different: a nostalgia for the past, especially among Victorians, for whom the late medieval period was an idealized time of the best art and the most noble chivalry. Today, if I want to buy paint, I can go into an art shop and find any number of tubes, each labelled with a name, number and a colored pattern to tell me what its contents look like. Some paints have descriptive names like “emerald green”; others have historical ones like “vermilion” or hard-to-pronounce chemical ones like “phthalo blue” or “dioxazine purple.” Others, like “burnt sienna” or “lamp black,” give clues about where the paint has come from and what has been done with it, even though it is unlikely that sienna still comes from the Tuscan town of Siena anymore, or that that particular black comes from lamps. If I feel overwhelmed, browsing along those laden art-shop shelves, the assistant will almost certainly have a chart to tell me the permanence, opacity or toxicity levels of my chosen paints, and will be able to direct me to a shelf of manuals that will tell me how to use them. But despite all this help it is easy for the beginner to feel a little lost. It is partly the terms—what, for example, is the difference between Cadmium red hue and Cadmium red? 4—and it is partly the sheer breadth of choice. But it is also the sense that, not really knowing what these paints are or where they have come from, one is somehow alienated from the process of making them into art.
That uncertainty about materials is not restricted to amateurs alone, nor is it restricted to the present day. In the eighteenth and nineteenth centuries, European artists were already beginning to feel alienated from their materials—and to sound alarm bells about this once they saw the cracks in their canvases. In April 1880 the Pre-Raphaelite William Holman Hunt stood before an audience at the Royal Society of Arts in London 5 and gave a speech that summed up his despair about artists’ loss of technical knowledge over the previous century or more.
The problem, he told his audience, was that artists had never learned the tricks their medieval predecessors had known from their first days as apprentices. What was the good of painting a masterpiece if its constituent elements would spend the next few years fighting together chemically on the canvas, and ultimately turn black? The early seventeenth-century painter Anthony Van Dyck knew how to employ varnish so that colors that would otherwise react with each other would be safe from ruin; Victorian artists, however, did not, and this was, Holman Hunt predicted, to be their downfall.
Part of the issue was that he—and his teachers, and his teachers’ teachers—had rarely had to mix paint from basic materials. He had never had to grind a rock, or powder
a root, or burn a twig, or crush a dried insect. Nor, more importantly, had he observed the chemical reactions involved in paint-making and seen how colors changed over the years. By his time, and in stark contrast with Cennino’s pre-paintbox world, almost all artists’ supplies were made and sold by professionals called colormen. Hunt was particularly passionate on the day he spoke—or at least the day he prepared his speech—because his own colorman had just sent him a bad batch of adulterated pigments, which had ruined one of his paintings.
The solution was not about doing everything oneself, he assured his listeners. Holman Hunt was the first to admit that some artists—like Leonardo da Vinci, whose patrons sometimes despaired that he would ever actually start the painting, he was kept so busy distilling and mixing—spent far too long on the preparation stages. After all, even the old-timers sometimes delegated— the excavations at Pompeii had unearthed paint pots in a workshop waiting for the artist to collect them, and Cennino himself had bought his vermilion ready made.
And the solution was also not to get rid of the colormen. Some were excellent, Holman Hunt said—recounting legendary stories of a pharmacist in Holland who could make vermilion that was “three times brighter” than anyone else’s, and of Michelangelo’s contemporary Antonio da Coreggio, who was famously helped to prepare oils and varnishes by a chemist whose portrait, in gratitude, “still exists in Dresden.” But what was urgently needed, he said, was for artists to spend time learning the basics of their trade, so that when they collaborated with colormen they would know what they were talking about.6
Colormen7 first appeared in the mid-seventeenth century, preparing canvases, supplying pigments and making brushes. In France some of them were originally luxury goods grocers, selling exotica like chocolate and vanilla alongside the cochineal, but most of them quickly turned to full-time art supplying. The arrival of these professionals on the art scene was a sign—as Cennino’s book was a much earlier sign—of how the act of painting was moving from a craft profession to an art one. For “craftspeople” the ability to manage one’s materials was all important; for “artists” the dirty jobs of mixing and grinding were simply time-consuming obstacles to the main business of creation. There were of course enough scare stories of charlatans adulterating colors to keep some artists mixing their own for several centuries. But slowly and irrevocably artists began to push their porphyry pestles and mortars to the backs of their workshops, while professional colormen (or rather, in some cases, the horses of professional colormen) did the grinding.
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