In Book X of his "Republic", Plato wove a tale describing the reincarnation of souls. Some modern theologians have speculated his vision was a genuine revelation, though difficult to unpack into words. The myth envisaged a cosmos enclosed in eight concentric spheres, as a model of the heavens. Each sphere had its own distinctive colour and musical note. The eighth note was the same as the first, but an octave higher; all eight, sounded together, produced the music of the spheres. De Clario prefaced the second night of "Sevenness: Sublunar" with a quote from Plato's myth of Er:
"And on each of its circles was seated a Siren on the upper side, carried round, and uttering a single sound on one pitch. But the whole of them, being eight, compassed a single harmony within the seven intervals."
Each sphere had its own note, matched in turn to a specific colour. They were not pure, but loosely described as 'whitish', 'yellowish', 'reddish', etc., suggesting the colours of dreams. To a spiritualist, the ineffable quality of the colours could indicate second sight. Equally, they may conjure up the idea of synaesthesia - of colours and sounds neurologically related - where one sensory stimulus (or even its concept) can excite a response from another sense. In fact, Plato was merely describing the planets and stars as seen with the naked eye, and allocated their natural colours and brightness each to a circle. But the axis piercing the spheres, holding both earth and the heavens together, was more vividly imagined. It appeared as a visionary shaft of light "in colour resembling the rainbow, only brighter and purer". In "Phaedo", Plato again described a higher reality of supernatural hues, "of which the colours used by painters on earth are in a manner samples". There, rocks were like precious stones, purples had a wonderful lustre, and whites were whiter than chalk or snow. In this upper realm, superior men and animals dwelt in the ether; common man, with duller senses, gathered around the Mediterranean "like ants or frogs about a marsh".
The powerful visions of Plato swayed the imagination of subsequent thinkers, pagan and Christian alike. Clement of Alexandria and St Augustine considered him the only pagan to come near the truth. Origen, in "Contra Celsus", speculated that Plato may have known the prophetic Hebrew scriptures - how else could he have described the celestial realm in "Phaedo"? - and he compared Plato's remarks on light to statements in the Bible. In AD 250, Plotinus allocated an important role to colour in his Neoplatonist philosophy. When light poured in to conquer the darkness of matter, emerging colours awoke the sense of beauty. Though not beautiful on their own, colours contributed to the beauty of visible bodies, when patterned and symmetrical. Similar rules applied to sound (though to a lesser extent), so that beauty in earthly music arose from the harmony of its parts. And John Chrysostom - John the golden-mouthed, a patriarch of the Eastern Christian church - traced beauty down the hierarchy to earth, around AD 400. He held the sky more beautiful than the earth, stars more so than precious stones, and the rainbow far more than flowers. Visible beauty itself was divided between upper and lower realms:
"The meadow below, and the meadow above; for there is a meadow on the earth, and a meadow too in the sky; the various flowers of the stars; the rose below, and the rainbow above!"
From time to time, religious authorities have banned depictions of sacred subjects. The iconoclasts of Byzantium, for example, went about the wholesale destruction of images in the early Middle Ages. We have witnessed an equivalent violence to artwork in our own era: in 2001, the Taliban dynamited second-century statues of Buddha in Afghanistan. Like the iconoclasts of old, they followed the dictates of religious zealots, to purge the country of false idols. The trend continues, with the current crop of murderers in Syria. Nor need one look so far from home; synagogues, churches and mosques in the West serve just as well as targets for fanatics.
Such fractious vandalism (in the Middle East or, indeed, anywhere in the world) is nothing new. In AD 787, the second Council of Nicea had attempted to reverse a destructive tide of iconoclasm. Depictions of Christ and Mary were welcomed, in "both gold and silver and of every colour", but "deceitful colouring of the pictures" was to be avoided. Handbooks were issued to control "the unlawful art of painting", and prescribed colours to be used when portraying saints, prophets and martyrs. (Artists, however, seldom seemed to follow instructions very closely.) Similar strictures applied to colours worn in real life; purple robes, for instance, could only be worn by members of the Imperial court at Constantinople. High status came at a great cost - over 12,000 murex shellfish were sacrificed in dyeing a single toga. The manufacture and trade of royal purple was traditionally a monopoly of Phoenecians, living along the seaboard of present-day Lebanon. When the Hebrew scriptures commented on the fine stuff of the Phoenecians, they sneered at "the prettiness of Tyre", but cloth hangings of their Tabernacle, and in the temple of Solomon, were dyed with the same Tyrrean purple. Christians, too, would clad the whore of Babylon in purple and scarlet - the costume of celebration in the Babylonian epic of Gilgamesh. At the same time, Christ (as in the mosaic above) was adorned in the same colours.
The moral equivocations of religion altered the symbolic significance of a colour, depending on its context. Even Christian clerics were at first confused, as to what to wear. Some were resplendent in robes embroidered with gold thread, to befit their station at court. As for the vestments of ordinary priests, these were originally an undyed white, or sober black and brown. More sumptuous costumes - of red, green and, occasionally, violet and other colours - were soon adopted for ceremonial use. Their colours were sometimes analogized to the elements - earth, water, air and fire - that were believed to make up the universe. The idea provoked differing reactions among the church hierarchy. While Gregory of Nyssa was to consider it a kind of virtuous contemplation (apart from any truth in the matter), Tertullian held the comparison to be idolatrous. Indeed, the symbolism of the elements had originated in pagan Greece, to become incorporated in astrological beliefs, medical and alchemical procedures, and the rites of magic.
According to Empedocles, in the 5th century BC, all matter arose from mixtures of the four elements. He likened creation itself to the work of painters, who "take many-coloured pigments to work with, and blend together harmoniously more of one and less of another till they produce likenesses of all things". The analogy invites the choice of four fundamental colours, to match the elements. His younger contemporary, Democritus, described all elements as white in their pure form, except for yellow fire, while black indicated matter in a transitional state. But even this was a convention, for a reality merely of atoms and void. In a parallel development, black, white, red, and a yellow-green were singled out, as basic colour sensations. Plato himself adapted the four-fold scheme, but substituted the quality of 'brilliance' for yellow-green. Not until the 2nd century AD, do we find the colours attached to elements. Antiochus, an Athenian astronomer, aligned them from black earth to yellow fire, though others took up different colours. Tertullian reported green earth, blue water, white air, and red fire. They originated, he said, in the liveries of the four main stables in Rome, which ran horse races at the circus. They also served as a naturalistic description for the seasons. Red summer, white winter, and green spring served the Romans, leaving blue for autumn. Nowadays, seasonal colours can be personalized, on the popular "Colour Me Beautiful" web site. A woman's hair tone - dark to light - and its colour - warm or cool - determine her 'season', in the hope she will purchase coordinated accessories, makeup, and a set of colour swatches.
Ancient Greek authors, from Democritus to Ptolemy, wrote on painting and colour, but their works are lost. Only the Peripatetic treatise, "On Colours", remains, dating from the 3rd century BC. It recommended that observations be made "not by blending pigments the way that painters do" but by "comparing the rays reflected by known colours". Painting was accorded a lowly status in the scheme of Greek ethics compared to music and dance. Plato and Aristotle made some remarks on colour, but seem to have considered painting as little more than a charming deceit. After making his musical universe in "Timaeus", Plato went on to attempt an explanation of colours. From combinations of four basic sensations - white, red, black, and the quality of brilliance - some nine further colours arose. As to proportions of the mixtures, Plato declared only God could fathom it. He derided any attempts to put number to colour, and the one extant text devoted solely to colour makes no attempt to do so. Scant few art objects survive, to demonstrate Greek virtuosity in colour mixing, though the names of famous painters, such as Apollodorus and Apelles, live on. Such is the legacy we have retrieved from antiquity. By relegating painting to an inferior craft, theorists ignored a most appropriate methodology available to them for studying colour. It is probable that contemporary painters understood the rainbow-like progression of colours to be got from mixing the pigments available at the time. It is but a small step from knowledge of the palette to methodical observations of spectral effects in nature - rainbows, waterfalls, thin films of oil, and so on. But the imaginative leap between practice and theory may have been more difficult than it now seems. Analytic investigation of the properties of light and colour were sidelined, or so it appears, by the weighty opinions of the great philosophers. Their few remarks barely constitute a colour science, and sometimes deflected investigations from a more fruitful course. When Aristotle wrote of the rainbow, in "Meteorology", he restricted its colours to red, green, and purple, claiming that:
"These are almost the only colours which painters cannot manufacture: for there are colours which they create by mixing, but no mixing will give red, green, or purple".
Aristotle was obviously wrong, since red alone is unmixed, while green is made from yellow and blue, and purple from blue and red. Alexander of Aphrodisias conceded as much, in a second-century commentary on "Meteorology". However, he defended Aristotle's approach, claiming that mixed green and purple were simply inferior. The same colours, he said, were better achieved from pure, natural pigments. Though their colours required no mixing, they were still manufactured - perhaps he felt they still fell short of the splendour of the bow. Just as there was a hierarchy of pigments, there were preferred methods of mixing. A true mix was something like a solution, according to Aristotle's "De Sensu"; unvarying colours resulted from complete interpenetration of the components. Otherwise, layers could be applied, like a painter's glaze or the haze across the sun that turns it red. The simplest way was to mix fine particles, a method followed by Robert Boyle in 1664. He made a green from yellow and blue powders, which could only be separately distinguished under a microscope. Boyle suggested their 'Compounded stroak' on the retina gave rise to a new kind of sensation. He speculated something similar might be said of two independently pleasing musical notes that, arriving at the ear simultaneously, produce a jarring discord.
Isaac Newton mixed dry pigments, too, attempting to prove all the colours produce a whitish result. Powders of yellow, green, blue, red, and purple were variously combined, in measured quantities - the result was mousy at best. Fascinated by prismatic lights, Newton also tested their effects on known pigments, shining single colours onto indigo, red minium, blue bise. Ancient theorists were rarely so experimental, being content to speculate on known phenomena. Some, such as the Roman architect Vitruvius, drew on a fund of experience; he provided a practical description of pigments, listing their origins, methods of manufacture, and various mixes and applications. Pliny extended the list to almost thirty pigments, though he was less experienced in their use. In his "Natural History", names became confused, and mythological elements were introduced. Later encyclopaedists, such as Isidore of Seville, embellished the Latin sources, to pass on a good deal of misinformation to the Middle Ages. The written record remained a poor guide to painting practice until the early 12th century, and the appearance of the manual "On Divers Arts", by Theophilus Presbyter.
The red paint called dragon's blood was imported from India as a thick vegetable lac. It was used to paint monochromes in ancient Rome. Pliny claimed it originated from the commingled blood of a dragon and an elephant, locked in mortal combat. The thrilling contest was shown in the Rein pattern book, of the early 13th century, and Leonardo da Vinci gave a blow-by-blow account, around 1500:
"The dragon flings itself under the elephant's body, and with its tail it ties its legs; with its wings and with its arms it also clings round its ribs and cuts its throat with its teeth, and the elephant falls upon it and the dragon is burst. Thus, in its death it is revenged on its foe."
Aristotle, in "De Sensu", made an attempt to regulate the order of colours. Between the poles of light and dark, he plotted a course from white, through yellow, crimson, violet, leek-green and deep blue, to black (with grey being a variety of black). The five intermediate colours arose, he supposed, from mixtures of the white and black extremes. From these seven, all other colours could be mixed. Aristotle compared them to savours, from sweet to bitter, "for there are seven species of each". The idea was to take hold in the Middle Ages, and quickly become conventional wisdom. At first glance, Aristotle's colour order seems sensible. By using black and white as standard measures, colours can be found that yield a tonal scale, from lightest yellow to the darkest blue. But, by no means would this procedure be certain. Any colour may vary tonally, yellow perhaps the least, and red can become as dark as most blues. Any darker greens and purples would also migrate towards the black end of Aristotle's scale. Conversely, any colour (including black) can be sufficiently lightened, that it may fall closer to white than a rich yellow.
Later authors made some small alterations to the Aristotelian colour sequence. The popular 13th century encyclopaedia, "On the Property of Things" by Bartholemaeus Anglicus, moved red to the centre of the scale. [Illustration 4, below] Since Aristotle stipulated all colours to be mixes of black and white, Anglicus decided that equal amounts would make red. He, and many that followed his lead, filled the place vacated by red with an extra yellow, a citrine. (The term indicates the emergence of orange as a distinct colour category, though some called it the more traditional saffron, or crocus.) John Guillem supplied the sky blue of blazon instead of citrine, for "Display of Heraldry" of 1610. The official colours of blazon were settled at seven (with a few minor exceptions), by the 16th century; it is notable that they are the same, at least in species if not in sequence, as Aristotle's seven. Even though heraldic colours had originated among the unrelated colours of planets, precious stones and metals, Guillem arranged them in a tonal order. Like most, he recognized five intermediate colours, made from the two extremes of black and white. He located them according to their distance from either end of the scale, or by their proximity to central red.
Cennino Cennini, in his practical "Craftsman's Handbook" at the end of the 14th century, made passing mention of the seven. Any suggestion, that each was made from black and white, would be laughable in a painter's manual. So he divided them into four mineral and three artificial pigments - a distinction found in Vitruvius and Pliny - before describing the many paint colours that were readily available. Of course, gradations of a colour were common in art practice. The painters of antiquity had mastered transitions from light to dark, and understood the limits in moving from one colour to the next. For example, a smooth passage between green and purple is achieved by an intervening blue, their common component. Unfortunately, Aristotle's blue lies on the other side of green, next to black. His scale is effectively broken in two - a warm scale from white, through yellow and red, to violet, and a cool scale from green to blue and black. Visual logic would require a spectrum-like progression, as found on colour-mixing diagrams. Aristotle used no prism or colour wheel to guide him, but he did have evidence in the rainbow. He chose to ignore it: his tonal progression was two dimensional, and could give no final running-order of all colours. A more balanced system would consider both hue and tone, as concurrent sequences, and some authors sought to apply more logical colours. Richard Haydocke, in his 1598 translation of Lomazzo's "Treatise on the Art of Painting", corrected one inconsistency when switching blue and green.
Of all the schemes that followed Aristotle, the "Colorum Annulus" of Robert Fludd (above right) is perhaps the most celebrated. His was the first printed colour circle, anticipating the colour-music disk of Isaac Newton, made famous in "Opticks" of 1704. While Newton derived his circle from measurements of the spectrum, Fludd's colours are related to urology (which occupies much of his medical book), since prognoses were made from the colour of urine. Medieval doctors had carried colour charts to aid diagnosis, which were sometimes drawn as many small flasks formed in a circle. Each flask held urine of a different colour, ranging from black to reddish, golden, white, and clear. Fludd intended his diagram to make a more general statement, about colour itself.
White, yellow, saffron, red, green, and blue, run anticlockwise round the rim, with black at the bottom. Red and green, positioned opposite white, are labelled as medium colours, containing equal amounts of light and blackness. Blue is mostly black, while the yellows differ in their proportions of white and red. Fludd illustrated the Aristotelian view, that colours were mixed of light and dark, and he believed the cosmos obeyed similar principals. Like colours, the universe was created when divine light emerged from primordial darkness. Encouraged by readings in Cabala and alchemy, Fludd considered colours, and other sensations, as essences, and extensions of the original creative process.
Albertus Magnus, the teacher of Thomas Aquinas, had declared the colors were divided arbitrarily into seven, to bring them into harmony with classifications of taste, sound, and smell. In 1550, the famed mathematician, doctor, and astrologer, Girolamo Cardano, took the analogy literally. He aligned white with sweet, and black with bitter, with five pairs of taste and colour in between. (He also conflated white with yellow, and black with dusky, due to ambivalence in Aristotle's text.) Julius Caesar Scaliger would attack Cardano in 1557, claiming mixes were made the way Plato described, and from the four elements, fire to earth, which he coloured yellow, blue, green, and white. Still, like Cardano and many others, he ended by listing the same seven colour species as Aristotle. Even those who played with prisms (Bernardino Telesio and Vidus Scarmilionius) concluded there were seven simple colours, though they moved green to the middle, where it is found in the rainbow. Telesio followed the spectral sequence closely, and thought its colours changed with the waxing and waning of the elements, and their associated qualities. He asserted the red end indicated warmth, the blue end cold, a notion that still divides colours today.
In some other texts, Aristotle had named green as a middle colour (including at the centre of the rainbow). His immediate successors found it a more restful colour than exciting red, and the ancients ground emeralds as a salve for the eyes. Green reminded medieval churchmen of spring, and some recommended green vestments as an alternative to red. In books on optics and heraldry, green was praised for its beauty and mildness, and, in 1490, the Platonist Marsilio Ficino described it as "the middle step in colours, and the most temperate". Cardano, on the other hand, made red the centre, saying: "We assume that white contains a hundred parts of light, scarlet fifty, black none". Aristotle, too, had suggested a way to estimate - if not measure - the amounts of black and white in colours. In "De Sensu" 3, he judged colours to be harmonious, if the proportions in their mixes resembled musical ratios. Then he considered them attractive, though few colours were accorded this honour.
After conceding, "it is possible to believe that there are more colours than just white and black", Aristotle singled out purple and red, to be compared to the musical intervals of a fourth (ratio 4:3) and a fifth (3:2). If black were the keynote, with white an octave above it, purple presumably contained four parts light, to three of dark. The ratio in red would be 3:2, of light to dark (not fifty-fifty, as Cardano and Anglicus asserted). (Aristotle's musical method should not be taken too literally - white might otherwise contain a measure of darkness, as well as two of light, to conserve the octave ratio of 2:1.) Learned gentlemen toyed at the scheme, with varying results, until a colour-music code of a more thorough kind emerged, in Isaac Newton's "Opticks" of 1704. It is interesting to speculate how the method might apply to all seven colour species, though Aristotle never went so far. Black, blue, green, purple, red, yellow, and white could fill the intervals of Greek music - within a diatonic octave of the Greater Perfect System - as shown below.
Mathematical ratios, whether ancient or modern, locate notes in the overall structure of a musical system. Such relationships had importance in an orderly universe, according to Plato. In "Timaeus" (the only Platonic dialogue known in Western Europe during the Middle Ages) he used musical structure to describe the cosmos. Greek music was more fully described in Boethius's "De musica", of about AD 500. From the 9th century on, scribes would clarify his text with arced diagrams, of the above kind. They located divisions within the Greater Perfect System, and marked the main Pythagorean ratios. For Aristotle, colours could have intrinsic harmony, too, accorded by the hidden balance of light and dark within them. He thought their virtues could be as expressed as musical ratios. Vincent of Beauvais agreed, in "The Great Mirror" of 1244, that proportionate colours caused delight. Like musical notes, they were governed by ratios that were compatible to the senses. White, for example, might shift a semitone, with the addition of a little red. (Today, we would presume they mix to pink, although yellow was the likely result on Aristotle's colour scale.) The red may have represented the fifth note, or was it a green? - details are skimpy and my Latin too poor to tell. Certainly the green, mixed with some yellow, gave most pleasure to Vincent's eye and ear. Purple and red were Aristotle's choices instead - colours valorized in antiquity, as the Tyrian purple and kermes red dyes of the most costly, honourable garments. Their degrees of lightness were expressed as musical ratios - the fourth, fifth and octave intervals. Though Aristotle elsewhere chose seven main colours (and Vincent reeled of the names of an extra dozen or so), not all were allocated a musical note. A selective approach to colour music, focused on the main Pythagorean consonances, encouraged the search for the most fundamental colours.
The polyphonic church music of Vincent's era combined contrasting voices in rich harmonies; octave intervals, with perfect fourths and fifths, were its chief accents and points of repose. Medieval musicians retained the Greek schema, as best they knew how, and the Pythagorean ratios were protected by Papal Bull in 1324. But tastes change, in music as well as colour, and fresh challenges emerged early in the 16th century. John Dunstable - representative of the contenance angloise - delighted in the sweet harmony given by the third. He preferred it to the fourth, and as the middle note of a triad of the first, third, and fifth. Together, they form the common chord we are familiar with today. The innovation became widely accepted by 1558, when the influential theorist, Gioseffo Zarlino, penned "Le Institutioni harmoniche". He was obliged to expand Pythagorean theory, to accommodate intervals of major and minor thirds, as well as the sixths. While justifying his changes with number mysticism, Zarlino also appealed to the evidence of the senses:
"The reaction of the ear to the combinations of sounds is analogous to the reaction of the eye to the combination of colours. Such combinations have a kind of harmony, in that they are composed of diverse colours."
In 1581, Filippo Mocenigo pursued ways of ordering colour, including by analogy to music. He retained Aristotle's red and violet - a hyacintinus - between black and white, but placed red a third from black (at a ratio of 5:4), not a fourth (4:3). Black, red, and violet formed a triad, of the type recognized by Zarlino, and equivalent to today's F major (F, A and c). Yellow was placed on the seventh note (e), while white completed the octave (at high f). Mocenigo likened the arrangement to five concentric circles, with black at the centre and white on the outer rim. As pointed out by Rolf G Kuehni (in the April 2007 edition of Color Research and Application), the array reminds us of Plato's myth of Er, its orbiting planets, and the cosmic harmony of colour and music. Mocenigo positioned further colours between black to white - enough to cover the eight notes of a musical octave. But he finally restricted their number to the traditional seven, and dispensed with blue altogether [see Illustration 4 above]. Like others who followed Aristotle, he would leave at least one note orphaned, without colour.
Mocenigo concluded that red, violet, and yellow (with black and white) were so pure, that all other colours originated from them. Vidus Scarmilionius, physician to the emperor Rudolf II in Vienna, took a close look at Mocenigo's ideas in 1601. He selected yellow, red, and blue as the simplest, but did not believe they could produce all colours, even with the aid of black and white. He discussed the perfect balance of elements required to produce simple colours, and how they appeared in the prism. Like Mocenigo, he analogized them to musical consonances - the fourth, fifth, octave, and the next fifth and octave above them. In the end, Scarmilionius rejected an harmonic approach, and settled for seven colours, graded from dark to light [see Illustration 4].
Curie de la Chambre took a similarly broad approach in 1650, stretching his colours over two octaves. So doing, he accommodated the seven colours of Aristotle (and, incidentally, of heraldry), at successive fourths, fifths and octaves. The method had another advantage: due to its symmetry, the scale could be read both ways, up and down, with white at either the highest or lowest note. (Zarlino himself had suggested white as the low note, on the grounds that large bells had lower pitches than small ones.) Individual intervals were all-important to de la Chambre, who drew multiple diagrams with arcs connecting all colours. He hoped to establish rules of colour harmony, based on music theory, and his ideas found purchase with the founders of the French Academy. If a musical interval were dissonant, the colours it represented would strike a disagreeable chord. Such was the case for red-blue and blue-purple combinations, while yellow, he believed, would clash with either red or purple. Green, however, was centrally placed, at the first octave, and, like black and white, would harmonize with all other colours. In this he followed the opinion of earlier philosophers, of Marin Mersenne and René Dèscartes, who agreed that green and the octave were most agreeable, and moderate in their action.
"The number of simple color species is five, and there are three species of mixed colors", wrote François d'Aguilon. The illustration provided, in his textbook on optics, was the first useful colour-mixing diagram to come off the presses. White and black (to left and right) enclose yellow, red, and blue, the three painters' primaries we are familiar with today. To show how other colours arose, d'Aguilon connected the five simple colours with a series of arcs. On the lower arcs, the three primaries - yellow, red, and blue - were linked two at a time. The resultant gold (or orange), green, and purple, were d'Aguilon's three mixed species, now known as secondary colours. His choice of simple colours was not entirely new - Chalcidius had emphasized the same five colours, around AD 300, in his Latin commentary on Plato's "Timaeus". D'Aguilon arranged them after the manner of Aristotle, in a tonal progression between white and black. He further acknowledged Aristotle's choice of red and purple, and their connection to sound, though he refrained from giving their musical ratios. However, the diagram itself was adapted from works on music theory, particularly Boethius's "De musica", where arcs were used to connect notes in harmonic proportions. But perhaps the greatest influence on d'Aguilon was the artist Rubens, who designed engravings for "Opticorum". He embellished the frontispiece of the textbook with a peacock (an ancient symbol of colour), and he may have acquainted the author with the painterly use of colour.
Athanasias Kircher adapted d'Aguilon's diagram in 1646, keeping much the same arrangement, and adding names for tints and shades of each colour. He appended an interesting table of analogies, including grades of tastes, from sweet to bitter - the sense originally aligned, by Aristotle, to seven colours. The elements were variously divvied up among the colours, as were five increments each of lights, of ages of man (from infancy to senility), qualities of mind (from intellect to ignorance), and of beings (from God to plants, with man in the middle). At the very last, he gave Greek names for musical strings, one for each of the five colours. They span an octave: the lowest note, at black, could be taken as E, followed by F, a, and d, to end on high e and white. (Though the diagram labels the blue string paramese, or b, I assume Kircher intended parhypate, or F. The sequence was corrected in later work, to places notes in ascending order.)
Colour correspondences, of Kircher's kind, have a long tradition. In "The Blazon of Gentrie" of 1586, Sir John Ferne provided no fewer than fourteen different parallels to the seven colours of heraldry (although music was not among them). The renowned philosopher al-Kindi, in 9th century Baghdad, had conjured up similar analogies from Greek and other sources. He gave each string of a lute its own season, element, and celestial region, dividing the bodily humours, stages of life, and faculties of body and soul among them. Kircher operated in much the same spirit, by adapting d'Aguilon's popular diagram. He elaborated his correspondences in "Musurgia universalis" of 1650, again giving colours to notes. In total, Kircher was to construct three colour-music codes, all quite different.
"All ye materialls (wch of themselves doe colour) are Red, yellow & bleu from wch (with fundamentall white) ariseth ye greate variety wee see in dyed stuffs."
Isaac Newton recorded the remark in his notebook, copying from Wm Perry's rules as read to the Royal Society, in 1662. The English chemist, Robert Boyle, also acknowledged the "Mechanical use" of red, yellow and blue by painters and dyers, in a 1664 treatise "Experiments and Considerations touching Colour". To study the matter further, scientists had to sweep aside conventional wisdom, so Newton famously insisted that colour was not a product of light and dark, as Aristotle had said. He undertook a program of refined experiments, to show we react to light alone. A naturally occurring progression of pure colour replaced the artificial order of hues, from dark to light. Surprisingly, Newton still divided the spectrum with musical ratio, as if in homage to the Aristotelian tradition. His red, orange, yellow, green, blue, indigo, and violet filled the seven intervals of a D scale.
So thorough was Newton's colour-music code, that it eclipsed the codes of others, and set a precedent for our own era. De Clario, for one, followed the same colour sequence, for the most part (right). The most important coincidences occur in the first, third, and fifth places, where a musical triad picked out the painter's primaries of red, yellow, and blue. No matter what musical key were chosen, the Newtonian system assured the root chord would highlight the same colours. For De Clario, the scale of C ran parallel to the spectrum, so primaries fell on the C major chord (of C, E, and G). That De Clario left the seventh position blank (or white) makes no difference: by omitted indigo, he merely reduced his palette to three primaries, plus the three secondaries of orange, green, and purple, stacked in vertical sequence.
A chief feature of De Clario's code is the assignment of human qualities to colours and notes. They conjoin at chakras, borrowed from Indian yoga, although similar attributes could just as well be drawn from Western history. Every colour has its accretion of myth, symbol and fancy, while music has been considered affective on the souls and emotions of men since the time of Pythagoras. Newton's colour music was a far more abstract construct, containing no explicit ethical dimension. It followed in the Aristotelian tradition, selecting individual colours from a coherent array, using musical methods. But all such enterprises are overshadowed by Plato's cosmology of Er, with its orbs composed of colour and music. The ancient analogies of the senses were not to be denied, and Isaac Newton was indebted to the tradition. Plato's quote, at the top of this page, might well be compared to the following note, which Newton sent to the Royal Society in 1675:
"And possibly colour may be distinguished into its principle degrees,
red, orange, yellow, green, blue, indigo and deep violet,
on the same ground, that sound within an eighth is graduated into tones."