By the age of sixteen, Roy De Maistre was playing music to some acclaim. He performed on the violin, sometimes accompanied by his sister on the piano, at local concerts in rural New South Wales. Three years on, we find him studying both music and painting in Sydney, and exhibiting artwork for the first time. His stencilled blotters and pipe-racks, shown in 1913 at the Sydney Society of Arts and Crafts, were noted by the press - chiefly as the only works by a man in an otherwise "splendid display of women's work". Henceforth, Roy De Maistre (or Roi de Mestre as he was then known) focused his energy on the visual arts, while maintaining a more detached interest in music.

In 1995, another Australian painter made the same career crossover - moving in the opposite direction to De Maistre, Domenic De Clario the painter became De Clario the musician. In a series of events, he played amplified music to his audience, though he remained hidden as if overcome by stage-fright. Maybe deliberate strangeness camouflaged uncertainty, and all would have been confusion had not De Clario expounded his beliefs in pamphlets of purple prose. He outlined a gestalt similar to De Maistre's - both used colour-music codes where spectral colours and the white-note scales of Western music were aligned in order of increasing frequencies.

De Clario advertised his colour-music code as a means to self-improvement, just as De Maistre had once used colour for psychiatric therapy. As if justified by these supposed benefits, each artist sought a broader platform from which to disseminate his views. From 1930, when in England, De Maistre attempted to realize music as paintings, and to apply his colour-music theory to ballet and film. Similarly, De Clario abandoned the more passive medium of painting to involve a group audience in a collective experience, as if it were good for them. Noteworthy as their individual efforts may be, they pale to insignificance beside equivalent spectacles staged by large organizations, aimed at great swathes of the general population.

Every civilization has had its multi-media events, combining colour and music, as well as words and movement. In ancient Sumer, the arts of public display were taken seriously. Music was highly refined, and Sumerians applied considerable mathematical skill to its theory. Different instruments, as well as their individual strings and tuning styles, were dedicated to a variety of deities, and music became an art fit for kings. For Culgi, king of Urim, it amounted to an obsession; he boasted of his skill with the lute and lyre, of his revival of old genres, and of the hymns he wrote for posterity. Colour was equally prized; garments of red, yellow, white, brown, and black are known, while varicoloured costumes were specially valued. Cloths of bright colours were acceptable as tribute payments or royal gifts, and were listed among the loot pillaged from sacked cities. Clay tablets from Sumer described processions held to honour the great goddess Inanna: armed men beat drums to a parade of the male prostitutes in service at her temple. The latter dressed in leather, each costumed as a man on the right side and as a woman on the left. His hair was adorned with multicoloured cloths and he carried skipping ropes of interwoven coloured threads. The ritual dances, plays, and games performed can only be imagined, anticipating anything from drag shows to rhythmic gymnastics.

Public ceremonies display the accumulated wealth and the high level of skills a people possessed. Apart from a certain vainglory, in service of god, king or country, the events are intended to gratify the populace and impress the outside world. At the chariot races in ancient Rome, colours had a strict function, identifying competing teams from different stables, each with its mass following. Other ceremonies of state and religion were equally formal, and punctuated with carefully chosen music. Philosophers would hold forth on the musical mode suitable for different occasions, and the appropriate choice of instruments. Colours, too, obeyed rules of traditional display, pinpointing the rank of a courtier, the function of a priest, or the allegiance of a sportsman. Woe betide any who sought to change the conventions, railed Plato, in Book 7 of "The Republic":

"Whereas if sports are disturbed, and innovations are made in them, and they constantly change, and the young never speak of their having the same likings, or the same established notions of good and bad taste, either in the bearing of their bodies or in their dress, but he who devises something new and out of the way in figures and colours and the like is held in special honour, we may truly say that no greater evil can happen in a state; for he who changes the sports is secretly changing the manners of the young, and making the old to be dishonoured among them and the new to be honoured."

Illustration 2 : BEIJING OLYMPICS,
closing ceremony, 2008.

Modern celebrations follow much the same pattern as the entertainments of old, overwhelming the senses with superabundant colour, sound, and movement. The opening and closing ceremonies of the Beijing Olympics in 2008 were just such events, changeable feasts of differently coloured themes culminating in spectacular fireworks. As a coordinating principle, the Chinese developed an 'environment of activating colors' for the Games. Chinese Red, Glaze Yellow, Scholar Tree Green, Porcelain Blue, Great Wall Gray, and Jade White were their fanciful names. The red, green, and blue were given sweeping significance, as representing culture, the environment, and science and technology, respectively. More particularly, blue evoked summer skies and the glazes of traditional blue and white porcelain; white jade was meant to bring good luck and symbolized intellectual honesty; and red stood for warmth and jubilance, as the colour of lanterns and for weddings. The grey was likened to the brick, tile, and stone of traditional dwellings. It was thought to supply a rich modern tempo, while providing a neutral backdrop to the other five colours. Together, the six were prescribed in a 'city colour directory', a sort of renovator's guide on how to spruce up Beijing for the Games. To justify this exercise in town planning, overseas examples were cited, and the "People's Daily" reported associate professor Cui Wei as saying:

"The city buildings in Salzburg all wear pinkish green [sic], red, blue, purple, orange and light gray. These beautiful but not aggressive colors not only decorate the city into perfect purity and beauty but also endow the brilliant imagination of the people with wings of music."

The 'environment of activating colours' used in Beijing 2008 was based on the design of the Olympic flag. The latter has five rings of blue, yellow, black, green, and red, on a white background. The six colours were chosen in 1913 (to combine all colours in flags of competing nations), and the Olympic rings remain one of the most widely recognized international symbols. Chinese designers created muted variants of the same hues, and each shade was specified by Pantone, CMYK, and RGB values, that could be replicated by anybody with a computer or a printer. Of course, red is China's national colour, too, and became the focus of a consumer craze during the 2008 Olympics - red refrigerators and red tea sets were popular, as was a USB stick coated in red lacquer. Conversely, protesters against human rights violations in China chose to wear orange, as a sign of dissent that would be hard for authorities to suppress.

Illustration 3 : EAST MEETS WEST -
reconstructed colour in modern China.

These differed from traditional colours of ancient China, when five colours (rather than six) was the official norm. They were associated with the five elements of earth, metal, wood, fire, and water. (At the same time, the Greeks had four elements - earth, water, fire, and air - with a fifth, aether, occasionally added later.) By 400 BC, the Chinese five-element theory was firmly established, and expanded to embrace government, society, and the heavens in a balanced, natural order. Five-fold divisions were to be found everywhere - among numbers, plants, animals, body organs and tissues, parts of the face, and human capacities and senses - as well as among the colours and musical notes. Of great significance was the colour yellow, symbolizing the earth and representing the authority of the yellow-clad Emperor, the measure of all things. At the start of each year, he rang out a note on the huang chung, the yellow bell. This established absolute pitch, and ensured harmony throughout the empire. The very dimensions of the bell were the basis for the system of weights and measures; subdivisions were found in the lengths and volumes of standard pitch pipes, which sounded the five chief notes in the pentatonic scale of music.

The elements were colour-coded, so five main colours became weighted with symbolic significance. Earth was given yellow, metal was represented by white, wood by blue-green, fire red, and water black. (Any distinction between blue and green was ignored in traditional Chinese, in favour of qing, a single term for anything from light yellow-green through deep blue to black.) The same elements were assigned to musical notes, to the tonic (kung), the major 2nd (shang), major 3rd (chio), a perfect 5th (chih), & to the major 6th (yu). All were linked by elaborate cross-references in the five-fold system, creating a colour-music code. The equivalent, in terms of modern Western music, would be C (yellow), D (white), E (blue-green), G (red), and A (black), in ascending pitch. There were, of course, notes and colours that do not fit the scheme; purple, for example, is not the red of fire let alone any kind of blue-green. And local variations arose, so the pernickety Confucius singled out the state of Cheng, as wicked and depraved in its use of both:

Other nations, and other epochs, have dressed their ceremonies in equally grand ideas, often backward looking, as if history might justify extravagant displays. The Renaissance princes of Europe, for example, had cannibalized antiquity, to parade in public as classical gods. They employed the most able minds of the day, to structure events around traditional themes of the seasons, the elements, and so forth. Cultural pretensions may be gratified by such a programmatic approach, but entertainments still rely on real and sensual elements - colour and music foremost among them. They are integrated in drama and dance, traditional forms that readily adapt to new technologies of light and sound. Modern spectacles have become replete with special effects, so that colour and music take centre stage while storyline waits in the wings.

At the Beijing Olympics, the old traditions were reduced to nostalgic references - a dose of history, as it were - in the promotion of modern China. Ancient metaphors, elaborated from the elements, have lost their relevance, and the Communist Party has long usurped the central role of the emperor. In any case, organizers needed to homogenize the experience, to attract the widest audience, so certain qualities were sacrificed. Much of the subtlety of traditional Chinese music was lost: apart from the mimed singing, nuances of timbre and pitch were obscured by amplification, and melodic structure was weighed down by Western-style orchestration. As for custom colours, traditional or modern, their symbolic functions may be learnt and retained, but their sensual impact is fleeting. None could convey a single meaning for long, by an audience overwhelmed with ever-changing colours in constant movement. And after action ceases and the music fades away, what remains? Besides merchandizing, a catchy song or a slogan, maybe a lingering trace of pentatonic Chinese music, and the memory of dazzling pyrotechnics.

Fireworks were invented in China, and their cascade of sparks against a night sky will please most people. They had been a fixture at public events in Europe since the late medieval period, but rockets were not coloured until the start of the 19th century when metallic salts were added to give brilliant reds, greens, blues, and yellows. The new art form invited its own theory: some praised pyrotechnics as a display of colour music. P Gonzaga, in his "Musique Oculaire" of 1800, compared them to L-B Castel's 18th century invention of a colour keyboard:

"Fireworks contain...the great advantage of never being constant, durable; combinations of shapes and colours develop in time, undergo changes and vanish rapidly, similar to tones, modulations and musical rhythm. Consecutive development and motion are essential here and contribute to the momentary enjoyment of changes. And, lastly, this is just the optical clavichord and, by its very essence, music for the eyes..."

In paintings, three dimensions are readily depicted on the flat surface (using perspective and so on), to give convincing illusions of space. By contrast, the fourth dimension of time can be alluded to (by shapes representing moving objects, for example), but action is inevitably frozen. There is a weakness if you will, in the medium of painting: while ideal for the display of colour, a painting cannot accommodate time. Ancient Greek philosophers recognized this limitation and held that only through movement and time could the highest moral values be expressed. As a result, dance, music, and even gymnastics were held in high esteem while painting had less consequence. The lowly status the Greeks accorded to painting have dogged the visual arts ever since.

Colour-music codes - those of De Maistre and De Clario being typical - have done nothing to redress this inequity. While they gave colour equivalents for individual notes, they provided no mechanism for translating the flow of music. The later paintings of De Maistre failed to disclose the nature of music or to render equivalent sensations, but functioned as esoteric and private music manuscripts. Some esoteric skill needs be applied to decipher them, in like manner to reading music from a score. (Conversely, the uninitiated may easily grasp a painting's sense of depth, with no knowledge of the complex perspective creating the illusion.) While a static painting can be an enduring object of contemplation, only a recording or performance will provide the musical sensation, where pitch and rhythm are manifest for an allotted time for what they really are. Ironically, we find ourselves back in the original Greek position, and poor painting is no better off.

"Those who have been in the habit of using a correct Kaleidoscope, furnished with proper objects, will have no hesitation in admitting, that this instrument realizes, in the fullest manner, the formerly chimerical idea of an ocular harpsichord. The combination of fine forms, and ever-varying tints, which it presents, in succession, to the eye, have already been found, by experience, to communicate to those who have a taste for this kind of beauty, a pleasure as intense and as permanent as that which the finest ear derives from musical sounds."

So wrote the eminent scientist, David Brewster, in "A treatise on the kaleidoscope" of 1819. Like Gonzaga before him, he compared the effects of moving colour to the 18th-century ideal of a colour keyboard. (Castel's original optical clavichord was a cause célèbre more than a performance instrument, though it is still considered the ancestor of all such devices, from colour organs to computer software.) But unlike Gonzaga, Brewster praised the kaleidoscope rather than fireworks. The public found the new toy fascinating. A tube containing coloured glass beads and lined with mirrors, it showed ever-changing symmetrical patterns when viewed through one end against the light.

Another scientist, J B Purkinje, was to note the effects of both kaleidoscope and fireworks, in his "Observations and experiments on the physiology of the senses" of 1825. He mentioned them as existing examples of "music of the eye", along with dance, gymnastics, ornamental gardens and altars. Purkinje was also an astute observer of colour: he was the first to note how reds faded in dim light while greens and blues became more intense (an effect now named after him). But the optical music he envisioned was allied to shapes rather than colour. In the new art form, the eye would instinctively follow the outlines of ornamental shapes, whether of spiral, circular or straight lines. Hopefully, the effects could be scaled up, but he was afraid that most contemporary examples were the work of buffoons.

The discussion of potential forms for a new art continued throughout the 19th century. Auditory and visual effects were to be combined in startling new ways, often in coordinated movement. Every advance in science, each technical innovation (notably gas, then electric lighting in theatres) provided fresh inspiration. Some, such as Purkinje, sought a physiological and psychological connection between sight and sound. Others saw the link as aesthetic, or emotional, and colour remained the main candidate as a visual equivalent to music. In 1875, H R Haweis was to write, in "Music and Morals":

"The only possible rival to sound as a vehicle for pure emotion is colour, but up to the present time no art has been invented which stands in exactly the same relation to colour as music does to sound. No one who has ever attentively watched a sunset can fail to have noticed that colour, as well as sound, possesses all the five qualities which belong to emotion... I select fireworks as an illustration in preference to the most gorgeous sunset, because I am not speaking of Nature but of Art ...and I select pyrotechny instead of painting of any kind, because in it we get the emotional property of velocity, necessarily absent from fixed colouring."

Illustration 5 :
"ALLEGRO CON BRIO: BOURKE STREET WEST",
Tom Roberts, 1880s.

The bustling movement on Melbourne's main thoroughfare was described by Roberts in musical terms, meaning 'lively and brilliant' when applied to performance. When Paul Gaugin wrote of orchestrating colour, he cast himself as a composer, concerned for the choice and disposition of hues and their combined effects. Using metaphor, painters could supply musical descriptions of their works, much as composers used visual similes for late romantic and impressionist programme music - moonlight, rivulets, and so on. It may be that innovative work is impossible to describe, that the best likeness can only be found in another, wordless language. Writers on colour music were more explicit, equating particular colours and notes, often intent on specifying relationships between colours like the harmonies in music.

Whistler, a leading exponent of 'art for art's sake', rejected such rule-bound approaches:

"As music is the poetry of sound, so is painting the poetry of sight and the subject-matter has nothing to do with harmony of sound or of color."

Illustration 6 : "HOMAGE À BLÉRIOT",
Robert Delaunay, 1914.

Robert Delaunay would later disagree: his style of painting - dubbed Orphism by the poet Guillaume Apollinaire - was theoretically based on the harmony inherent in sunlight. Delaunay believed a simultaneity (or synchronous movement) of light was manifest as the action between different colours. How would this look on canvas? "Halos here and there halos, movements of colour", he told the German Expressionist August Macke. Something of the kind might be read into his "Homage to Blériot", celebrating the feats of the great aviator and the exciting new movement of powered flight. Delaunay wrote to the painter Wassily Kandinsky that his theory was based on studies of colour transparency, "whose similarity to musical notes drove me to discover the 'movement of color'". The art critic A V Lunacharsky was one to encourage the musical connection in 1913:

"Music of colours, a symphony of tints and linear melodies is quite conceivable, particularly when merged with the music of sounds. But it is dynamics that form the foundation of music - to draw level with it the subtle artistic kaleidoscope of the best Orphists should also become dynamic... Let innovators of painting give us a chance to observe the splendid play of lines and colours engaged in that struggle of dancing sounds, that abstract round dance which is found in music."

Delaunay found the play of colours in complementary and simultaneous contrasts. He referred to the voluminous "On the Laws of Simultaneous Contrasts of Colours", published by the eminent chemist M-E Chevreul in 1839. (The pointillist Seurat had used the same work to justify his painting technique, in the 1880s.) The laws gave substance to Delaunay's notion that colours were in motion. He united these optical effects with the movements of vision in one creative rhythm. Whether colours could truly move, of themselves, is a moot point: even Apollinaire, chief apologist for the Orphists, had to concede that any impulse came from elsewhere:

Around the same time, A B Klein was making colour-music paintings that looked like patches of sky or clouds. He considered their colour harmonies better than anything produced by Kandinsky, and less garish than the works of the Synchromists. Still, the results were merely pretty and Klein decided, "Painting is no longer a vital art. The state of affairs is more or less desperate". He abandoned the easel for moving displays of coloured light, and published his authoritative "Colour-Music: The Art of Light" in 1926. Klein emphasized machines that could create colour music automatically; he was anticipated by A W Rimington, a pioneer of performances on the colour organ from the end of the 19th century. The latter had written his similarly titled "Colour-Music: The Art of Mobile Colour" in 1912. Rimington considered the colours of the Impressionists, or even Turner, were surpassed by projected light from his organ. The musical analogies of Whistler were found wanting, and he explained why painting was an inferior vehicle for colour music:

"But in most pictures colour has necessarily remained subservient, to some extent, to their subjects, and in any case a picture cannot give more than one colour scheme, or the solution of a very few problems in colour within the boundaries of its frame. Once painted, moreover, that scheme, harmony, symphony, or whatever the artist may call it, remains fixed and unaltered. At most it is a chord or two of colour, or a single colour-phrase, even though much may be sacrificed in expression of the subject of the picture, or even in truth to nature, to make that chord or phrase harmonious or interesting."

A new medium was emerging as a vehicle for colour music, that was likely to supplant not only painting, but also fireworks, fountains and even colour organs - the motion picture. Since early films were silent, the action on the screen was frequently accompanied by live musical performances. With sound track added, a film can be ideal for conveying musical ideas. (Imagine any musical without the songs - that would be an entirely different movie.) The first films were also black and white, so special scenes were often hand coloured to emphasize the mood - blue for night-time, red for fire and passion, and so on. (An uncoloured film is unthinkable today, except in the context of arthouse cinemas.) Both music and colour are carefully designed for modern films; still, they are rarely more than an adjunct to the main plot line, as portrayed through time and motion, speech and action.

Many visual artists who are also musicians find film the ideal medium in which to express themselves. As time is the primary dimension of music, so too does film have duration. Where musical time is divided by rhythm, changing shapes and colours on a projection screen can keep time to the accompanying music. From 1912 onwards, art films have been produced to convey musical ideas with abstract animation. Their moving lines and changing shapes were used to parallel the feeling and intent of particular scores, as much as their musical structures. At first, form provided the metaphor for rhythm (though sometimes it had additional significance, as an alchemic or Theosophical symbol): colour played a subordinate role, partly because early film was black and white and each frame had to be laboriously hand-coloured. Generally, colour was not coded according to any given notes or keys, nor meant to stipulate any synaesthetic relationships. Rather, rhythmic changes of light and colour supplemented the forms to display musical content and character to the best advantage.

With the advent of talkies, experimental filmmakers found they could couple visual images to sound effects on the one strip of celluloid, and were quick to exploit the correspondence. Lazlo Maholy-Nagy's "The Sound ABC" of 1933 used the same visual symbols (letters, faces, signs and so on) on the optical sound track as were shown on the screen. This 'light-hearted experiment' showed that each image could produce its own unique sound. In Russia, the composer Rimsky-Korsakov was also experimenting with patterns and shapes to optically generate musical tones. Animators throughout Europe began using their own designs, freehand or geometric, to make synthetic sound. Within the limits of film technology, sound and image had become one.

Alternatively, music took the lead and images were carefully synchronized to a set score. Some photographed their work frame by frame; others drew directly onto the film stock itself. Yet others improvised: Oskar Fischinger projected coloured lights onto screens to accompany the piano music of Alexander Laszlo. They met at the Colour Music Conferences held every three years in Hamburg, where synaesthesia, perceptual psychology, notation and the interface of painting, dance and music were discussed. But German creativity was stifled when the Nazis rose to power and declared all abstract art degenerate.

Meanwhile, Mary Ellen Bute was making the first abstract art films in the USA. Having helped Leon Theremin present his thesis, "The Parameters of Light and Sound and Their Possible Synchronization", she went on to create filmic impressions of music. At first, Bute built her imagery around mathematical formulae but later used an oscilloscope to choreograph a repertoire of forms to chosen scores.

The Whitney brothers, one a composer and the other an abstract painter, also used technology to aid them in the production of animated films. They originally used pendulums to activate an optical wedge and expose the sound track. Though the pendulums themselves produced no sound, they were so finely tuned to harmonic lengths that a rich and complex music was heard when the film was projected. Simple geometric forms supplied the imagery; these were arranged across the screen and in sequence according to fixed rules, derived from musical forms such as the canon and the 12-tone scale. The Whitneys were fascinated by the periodic waveforms of sound; by the mid-l960s they had pioneered the use of computers, to create animations based on the mathematics of music:

"Using the computer to create periodic visual action with a mind to reveal harmonic phenomena.
To create tensions and resolution and to form rhythmic structures out of ongoing repetitive and serial patterns.
To create ordered variation of changes. To create harmonies in motion that the human eye might perceive and enjoy."

The mathematical tendency reached some kind of culmination with Tony Conrad's film "Flicker", of 1965. To barely audible electronic music with a very rapid beat, a variable stroboscopic effect was projected as the only visual element of the work. Alternating transparent and black frames produced flashes of pure white, at rates moving in and out of the range of 8 to 16 cycles per second that corresponds to the alpha rhythms of brain waves. Though the author theorized about harmonic relationships akin to music (with the standard projection rate of 24 frames per second supplying the tonic), he admitted that "Flicker" was conceived as "a hallucinatory trip through unplumbed grottoes of pure sensory disruption." An hypnotic state accompanied by illusionary colours and images is supposed to result, though many find the film purely excruciating.

Since World War I, stroboscopes have been used to treat battle fatigue, as a brain-washing technique, and in tests for some epilepsy: it was appropriate that Conrad should add a legal waiver to his film, to avoid reparations if someone threw a fit. The reality of this danger became clear in 1997 when a cartoon shown on Japanese television, including several seconds of bright and rapidly-flashing red, white and blue lights, sent over 700 children into convulsions.

The flicker effect was used for more benign ends in Paul Sharits' 1968 film "N.O.T.H.I.N.G." By varying colour and tone from frame to frame, he hoped to create rhythmic sensory impressions. Overall, colour progressed through white, yellow, red and green, to blue, following the program of the Tibetan mandala of the Five Dhyani Buddhas. This tonal scale of colours, from the lightest to the darkest, was meant to promote awareness and the highest level of inner consciousness in the viewer. (His graphic device of mandala gave different colours to either the Tantric meditation on the four chakras, or the seven chakras of kundalini yoga. A Western derivation, the colour-music-chakra code, uses seven colours in a spectral array rather than in their tonal progression: all, however, are aimed at achieving enlightenment.) But more than the symbolic colours of the mandala, the accompanying sound of the mantra was paramount for Sharits. The ultimate OM was represented, at blue, by a steady vibrational hum. Though electronic sound supplanted music on the soundtrack, Sharits considered the film as a composition, making music on a metaphoric level.

The work of abstract artists has always been in the vanguard of animation, though it is usually overshadowed by populist cartoons and video clips at the cinema and on TV. Only in the more personal (and relatively new) world of the internet has an interest in unity of sound and vision regained prominence. Some of the most durable and elaborate sites on the net are devoted to systems analogizing sight and sound: many sport technical wizardry and quote scientific theories, others rely on faith in a mystic, holistic unity of all phenomena, but all presume the combined effect of musical and visual stimuli has a profound human resonance. Traditional colour-music codes can still be found sheltering in web sites, with colour-sets of ROY G BIV (or else the painter's primaries) listed as incontestable fact. Often they are couched within a broad mythology dealing with the I Ching, astrology, spiritualism and the like. There they flounder under layers of obtuse meaning, inaccessible to all but the most devout readings. Eventually, colour music is likely to be subsumed in mainstream concerns, where the trend is towards less proscriptive methods and more inventive techniques, for uniting sight and sound.

Software for the computer can now produce sound from any image, or vice versa, depending on the sophistication of the program and the power of one's machine. Apple's popular iTunes includes a Visualizer on the menu bar that converts any music being played into moving shapes, patterns and colours. Its images are remarkably well synchronized to the sounds, though I suspect much of this is a coincidence and relies on the speed with which audio signals can be converted. Some ingenious users, not content with the brand imagery, have written their own Visualizer programs that can be added to the menu. Their effects are often more subtle, but with less scope than the original.

Some programmers have branched out on their own, using unique algorithms, to provide us with software bridging the colour-music divide. The commonest visual read-outs range from simple graphs (oscilloscope waves, moving colour-bars, etc.) to mandala forms of changing colour and complexity. Sound can be produced from any scanned image, pixel by pixel, according to colour; other programs can read and write music scores, as well as orchestrate existing sound. A degree of personal choice is often allowed - sound quality might be controlled, shape and colour preferences may be stipulated. A variety of apps is available for mobile phones, allowing customized displays whenever music is played. The best artistic results are often personal, even arbitrary interpretations, free of rules that can inhibit expression.

Some software uses the irregularities present in heartbeats, or the coding of DNA sequences, as a mathematical base for linking sight to sound. They may employ traditional methods as well - such as aligning cycles of musical fifths to a specific gradation of colour - to translate the data into a comprehensible form. Whatever process is used, it is the computer programmer at the one end, and the individual user at the other, who dictate the audio-visual result. But perhaps the most customized interactive tool is IBVA, designed to harness the user's brainwaves, to navigate other software, to manipulate other equipment and trigger both sound and image. Its approach reflects the contemporary fascination, among scientists as much as mystics, for biorhythms as a predictor of aesthetic responses.

In the realm of multi-media, sensory fusion has just begun. One would think that computing, with its mathematical base and audio-visual capabilities, would be the ideal medium for colour music to flourish. And flourish it should, without the imposition of a dogmatic code. The mathematical codes (some of them the usual colour music formulations) that form the basis for earlier software, are likely to be surpassed; their refined concepts will probably prove limiting in general applications. Changes inside the computer and screen will dictate how sounds and colours are produced; flexible software can incorporate these elements in multipurpose programs, driven by new methodology rather than old formulae. Commercial considerations, as well as technical sophistication, will cater to public demand, for popular products that maximize results with the least effort. Lest the outcomes become homogenized and dull, let us hope that creative artists, animators and musicians continue to be involved. They were among the first to explore the meeting of sight and sound, to give invention a practical form. Their work across different disciplines is a valuable impetus at times of change, in breaking with cloying traditions.

However, some old theories have proved remarkably tenacious. Ideologies for reconciling the senses, through mathematics and spirituality, re-emerge time and again - despite technical and philosophic innovation. The colour-music code, with its arrangement of spectral colours and a white-note scale, is one idea that is never far below the surface. Some of its major tenets influenced early animated film, even though colour had less theoretical importance than form as an equivalent for music. Paradoxically, it occasionally appears in painting, as a transcription code for achieving the impossible - accommodating music in a medium with no time frame. Codes per se may be a disadvantage in the long run, sterile and antiquated encumbrances. But, hopefully, computer users will take inspiration from the abstractionists and animators of the 20th century, to continue making open and unfettered explorations of colour and music.