A Colourful History
Can human art improve the rainbow? Rainbows have inspired artists and scientists over the centuries to create fountains, instruments, and machines to take the rainbow to new heights of spectacle and discovery.
Rainbows are a natural wonder, an awe-inspiring display of colour caused when sunlight is reflected and refracted in raindrops to split into its constituent colours of red, orange, yellow, green, blue, indigo and violet. Not content with the familiar arc, Nature creates an amazing variety of rainbow-like phenomena, from multicolored halos called ‘solar glories’ to ‘fogbows’ and the ‘moonbow’, an eerie white rainbow generated by lunar light. Surely there is nothing more to add to the rainbow?
Surprisingly the answer is yes. Before the seventeenth century, many Europeans believed that there were two kinds of rainbow: natural rainbows in the sky and “artificial” rainbows created by human ingenuity. The spray of a fountain, when viewed at the right angle by a person with their back to the sun, produced a rainbow effect, prompting the creators of princely gardens to design purpose-built fountains producing “artificial” rainbows for the entertainment of courtly guests. In the European renaissance, spectacular “theatres of water” proliferated in aristocratic gardens, where engineers generated a “third nature”, using art to surpass even Nature’s own creations.[i]
Around the world, artists created spectacular rainbows in pigments and print, often resonant with spiritual and symbolic meanings. Aboriginal rock paintings show the rainbow-serpent Burlung who lived in the rock upon which he was painted.[i] As fans of Thor will know, Norse mythology imagined a rainbow bridge, the Bifröst, connecting the realms of gods and men. In the thirteenth century the Persian astronomer Zakariya al-Qazwini illustrated a manuscript on the wonders of creation with a beautifully-illuminated rainbow with each colour outlined in gold.[ii] Islamic scholars explained the production of rainbows through reflection and refraction in raindrops, an idea also worked out by the French philosopher René Descartes in the seventeenth century. Descartes used his new theory to propose a better version of the rainbow fountain, by spraying different liquids whose varying degrees of refraction could be controlled to produce signs in the sky.
Descartes also showed that natural and artificial rainbows are one and the same. But this didn’t stop artists and scientists from creating new rainbows, amazing audiences and making new discoveries about the nature of light and colour along the way. Soon after Descartes, Isaac Newton used glass prisms to show that sunlight could be split up into all the colours of the rainbow, and each colour couldn’t be divided any further. Previously people thought colour was a modification of white light, changing indefinitely as you added more white. Scientists also explored the relationship between light and sound. In the eighteenth century the French mathematician Louis Bertrand Castel proposed the “ocular harpsichord”, an instrument with a rainbow keyboard like a piano that played coloured light instead of musical notes. Castel supposed a parallel between the seven colours of the rainbow and the seven tones of the musical scale. The harpsichord was never built but was surely a forerunner of today’s spectacular music and light shows at rock concerts and fireworks displays.
In the nineteenth century, scientists created an array of extraordinary instruments for investigating the production of rainbows. In France, a priest called Raillard used an apparatus that altered the size of water droplets to show how the rainbow’s colour weakened as the droplets became smaller. In England, the physicist John Tyndall used liquids of different densities to make further investigations.[iii] He set up a watertank on the roof of the Royal Institution in London to produce a spray in rooms below that could be used to study the rainbow.[iv] Clad in a waterproof sou-wester coat, Tyndall lectured surrounded by rainbows and immersed in mist he generated with a copper steam boiler.[v] He was first to show that white “fogbows” were created from mist like rainbows.
New technology put rainbows at the cutting edge of special effects. Electric arc-lamps invented around 1800 became ever more powerful in the nineteenth century, enabling the creation of spectacular artificial rainbows. The French inventor Jules Duboscq created a “perfect rainbow” for Rossini’s opera “Moses” in Paris using newfangled electric light shining through a prism.[vi] Richard Wagner tried (and failed!) to repeat the effect for the rainbow bridge in Das Rheingold.[vii]
In the twentieth century, rainbow art signalled optimism, hope, and scientific progress. An “immense artificial rainbow” greeted visitors to the Paris Exhibition of 1937, arching over the entrance to a “Palace of Discoveries” featuring displays on infra-red and ultraviolet light, a planetarium and an artificial sunset.[viii] Though ultimately overshadowed by tragedy, the 1972 Olympics in Munich were designed to be the “rainbow games”, a celebration of optimism embodied in a magnificent rainbow-coloured Dachshund mascot called Waldi. The “Sky artist” Otto Piene created a colossal 2400-feet long inflatable rainbow which was filled with helium gas to make it float in the air above the Olympic stadium.[ix] Rainbows long retained their resonance as political symbols. In the 1920s, the “Rainbow Pool” was completed between the Lincoln Memorial and Washington Monument in Washington DC, displaying sparkling waterjets and rainbows at the heart of American life.[x]
Scientists and artists continue to experiment with rainbows right up to the present day and have taken them into the virtual realm. Recently Icelandic-Danish artist Olafur Eliasson installed shimmering mists of rainbow colour in galleries in Seoul and London, encouraging visitors to walk around inside them.[xi] In 2011 UC San Diego researchers Iman Sadeghi and Henrik Wann Jensen simulated most forms of rainbow formation in a computer, discovering that air pressure on falling raindrops alters their shape into one like hamburgers. Discovering what they called “burgeroids” enabled the first simulation of ‘twinned’ rainbows, previously unexplained.[xii] Now Bompas & Parr are pioneering a flavoured rainbow at the Royal Docks, using taste to bring a whole new sensory dimension to the remarkable story of the artificial rainbow. Who knows what new discoveries await us as new technologies emerge? The future of artificial rainbows looks bright!
[i] Simon Werrett, “Wonders Never Cease: Descartes's ‘Météores’ and the Rainbow Fountain,” British Journal for the History of Science, 34 (2001): 129–147.
[ii] Jan Jelínek, “The Social Meaning of North Australian Rock Paintings,” Anthropologie 14 (1976): 83-87.
[iii] Walters Art Museum, manuscript W.659, ‘The Wonders of Creation’, <https://art.thewalters.org/detail/83958/rainbow/>
[iv] John Tyndall, “Note on the White Rainbow,” London, Edinburgh and Dublin Philosophical Magazine and Journal of Science 17 (1884): 148-9.
[v] John Tyndall, “On Rainbows,” Popular Science Monthly 24 (1884): 659-673 on 669.
[vi] Roland Jackson, The Ascent of John Tyndall (Oxford, 2018), 416-17.
[vii] Ward Leonard, Theatre Lighting Past and Present (New York: Ward Leonard Electric Lighting Company), 19-20.
[viii] Patrick Carnegy, Wagner and the Art of Theatre (2006), 86-7.
[viv] “The Paris Exhibition” Bystander 134 no. 1744 (May 19, 1937), xvi.
[x] “Otto Piene’s Sky Art,” https://vimeo.com/17036813
[xi] “The Return Of the Rainbow: Restoring a Fountain on the Mall: The ‘Rainbow Pool’,” Washington Post (14 May 1988): 1.
[xii] Alex Landon, “There’s A Room Full Of Rainbows Inside Tate Modern,”, Secret London (July 9, 2019) <https://secretldn.com/tate-modern-olafur-eliasson/>
[xiii] “Computer Simulations Shed Light on the Physics of Rainbows” UC San Diego School of Engineering, December 2011 << https://jacobsschool.ucsd.edu/news/release/1144>>
Simon Werrett is professor of the history of science in the Department of Science and Technology Studies at University College London. He writes on the history of science and art. His book Fireworks: Pyrotechnic Arts and Sciences in European History appeared in 2010.