Periodic Tales

by Hugh Aldersey-Williams

  How significant to the museum’s success–and the city’s renewal–is the metal that is responsible for everybody’s first impression of the building? Its novelty, dutifully noted by every press reporter, implies bold innovation, on the part of the architect certainly, but also on the part of those who commissioned the work. The material is futuristic, and so the building becomes a monumental statement of optimism for that future. Yet the forms into which it is shaped simultaneously evoke the shipbuilding heritage of Bilbao, and so appear respectful of the past. Material, form and site converge to demonstrate that uncompromising modern architecture can nevertheless belong.

  A less generous interpretation is possible, however. Marooned a couple of blocks from the life of the city, the Guggenheim Museum seems to hold itself aloof, its alien presence heightened by the wanton exoticism of its shapes and materials. It is an airdropped package of cultural imperialism, its metal no more than a flashy façade that fails to disguise the shortage of great art within, a gratuitous flashing of a foreigner’s wad of cash. The building’s glittering titanium plates have been compared to fish scales, a recurrent Gehry motif. But to one critic, ‘they look more like money, silver coinage pressed into the building material’.

  The Walt Disney Concert Hall in Los Angeles provides an informative comparison. This, if anything, should have been the more significant building for Gehry. The project predates the Guggenheim commission–Disney money was donated and Gehry’s design completed by 1991, but later delays in fund-raising and construction meant it was not finished until 2003. It was also the first major commission Gehry received from the city where he has long lived and worked; it might have been expected to represent an important milestone in the career of an architect then entering his eighth decade. Gehry had first proposed to build in stone, but the experience of the Guggenheim prompted him to change to metal cladding. No titanium here, however. The Walt Disney Concert Hall is covered in stainless steel that was found upon completion of the project to be so shiny that it had to be sanded down in order to disperse the sunbeams it was sending into nearby apartments. Critics see it as the superior work. ‘The façade of Disney Hall is more refined than that of the Guggenheim, and more sumptuous, even though it is made of stainless steel, a cheaper material than titanium,’ wrote Paul Goldberger in the New Yorker. But it has not lived up to the hype that it would surpass the Guggenheim in its global impact. There’s been no Californian version of the ‘Bilbao effect’. Whether it’s the glow of technological optimism, or just the golden tinge of lucre, titanium clearly has something that steel does not.

  The March of the Elements

  Are there elements that we consider precious or exotic today, as Parisians considered aluminium throughout most of the nineteenth century, but which will one day lose their cachet? Is titanium, for example, now on the road to banalization? And if so, what will come after it?

  It seems too soon to tell where titanium will find its place. For now, it leaves too many questions unanswered. What, for instance, is titanium’s gender? This question seems odd, but its answer is important if we are to know what to use it for. In culture, it has long been determined that gold and iron are masculine and silver is feminine. Titanium-branded sports gear is clearly pitched at men, but colourful anodized coatings have made the metal popular in jewellery for women. At this moment in its history at least, titanium may be masculine or feminine, both or neither. ‘It liberates one from those classifications,’ says David Poston.

  At the Edinburgh College of Art, Ann Marie Shillito has also been using titanium for making jewellery, using its lightness and the colours it produces through anodizing to stake out an aesthetic territory some distance away from the heavier precious metals. The metal’s low density (only aluminium and magnesium are lighter among the practical metals) allows her to make items such as earrings larger than they might otherwise be. Yet the fact that titanium work-hardens faster than other metals makes it very strong, too. A misplaced bend in the metal cannot simply be unbent, which makes it a demanding material to work with. Shillito has been asked to make men’s wedding rings in titanium as well as earrings for women. But others are put off by the metal’s space-age lightness, unable to forget the cultural conditioning that associates greater value with greater weight.

  This conundrum has prompted Shillito to look again at the periodic table. ‘That’s when I switched to niobium,’ she says. In the periodic table, niobium sits in the row below titanium, which means that it is denser. Shillito also works with tantalum, in the row below that, the row containing the real heavyweights, tungsten and gold.

  Niobium and tantalum often occur together in minerals, and their discoveries were consequently a matter of some confusion and frustration, one reason why the two elements were eventually named for Tantalus, condemned by Zeus to stand under a tree whose fruit always remained out of reach, and his daughter Niobe, the goddess of tears. ‘Niobium is twice the density of titanium and half that of tantalum. It is close to silver in this respect and feels more precious than titanium,’ Ann Marie explains. When mass-produced titanium jewellery made it hard for her to sell her more expensive, individually made pieces in that metal, she started working wholly in niobium, which commanded a higher price because people felt it must be more valuable. But the different material also demanded a different way of working. Niobium is more forgiving than titanium, allowing Shillito to manipulate it in ribbons and sheets. Her designs in niobium appear spontaneous and free in a way that was impossible in titanium. The heavier metal also behaves more controllably during anodizing. With titanium, the artist cannot be sure what colours will be produced–Ann Marie enjoyed the element of chance that crept in after the exactitude the material demanded of her while she was shaping it. But with niobium and tantalum it is possible to tune the anodizing voltage to produce a desired colour with such accuracy that jewellery can be made to match a customer’s wardrobe.

  Ann Marie shows me some titanium pieces she has inlaid with niobium and tantalum. Like other precious metals, the heavier materials are relatively soft and can, using a laser, be worked like plasticine to produce decorative textured surfaces, albeit fused to a tough titanium base. The anodizing voltage produces different colours in the three metals. Into a brooch made of a sheet of titanium–brushed matt, mid grey with a hint of green–she has hammered small, bright lozenges of niobium anodized in bright colours. Many people assume the colours are added on in some way like enamel, she says. They do not realize that they are intrinsic to the metal and its thin oxide coating–as in butterflies’ wings, it is an interference effect of the light reflected from the surface that causes the colour rather than any pigment or dye. In time, perhaps, these rainbow shimmers will be seen as characteristic of these elements, just as verdigris is to copper and tarnish is to silver.

  This is the march of the elements into our lives. To the Phoenicians and Romans, tin and lead were the prized new materials of the day, acquired with difficulty and danger from the remotest sources, unattended at first by any mystique or mythology, but loaded instead with the miraculous novelty of nature. Now titanium has found its way from the mines into the laboratory, and from the laboratory into the workshop and factory, and is finding its way into our culture. For niobium and tantalum, that journey is just beginning.

  Part Four: Beauty

  Chromatic Revolution

  Clearing out some old boxes, I find my father’s old Winsor & Newton artists’ paints, which he used during his teenage years in the 1940s. The black metal box opens to reveal a scene of carnage. The little tin tubes of paint lie twisted like corpses in their narrow compartments, frequently stuck down with linseed oil that has split from the pigment, and occasionally caked with colour that has bled from the ruptured tubes. I turn them and read the labels: Chrome Yellow, Chrome Green, Zinc White; Terre Vert, made from iron silicate; Viridian, another chromium colour; and others too crusted or rotten to decipher. Some colours are all but banned these days, replaced by innocuous sy
nthetic pigments not quite their equal, but in this set I find even more outré pigments such as Vermilion, the brilliant flamered based on pure powder of the poisonous mercuric sulphide, and greens rich in arsenic.

  It was one further element, however, that provided more and brighter artists’ pigments than any other. Friedrich Stromeyer’s discovery of cadmium was to unleash the loudest riot of colour art had ever seen, and he knew it from the first.

  In 1817, Stromeyer was a professor of chemistry and pharmacy at the University of Göttingen and also held an official position as inspector of apothecaries in the state of Hanover. One of his inspections revealed that a preparation of medicinal zinc oxide was clearly not what it purported to be. When he heated the substance, Stromeyer found that it turned yellow and then orange. This would normally indicate the presence of lead–and the need for enquiries into who was making up false remedies. But further checks were negative for lead. Stromeyer pursued his investigation to the chemical factory that had supplied the pharmacy and took a sample of the suspect material away with him for further examination at his own laboratory. Here, he deftly identified the cause of the anomaly by using a series of chemical procedures to remove the known zinc. When this was done, he was left with a pea-sized lump of a bluish-grey metal, rather like zinc in appearance, but shinier. This was the world’s first glimpse of a new metal, which was duly called cadmium after the Greek for the zinc ore calamine, with which, it soon emerged, it was often found.

  Stromeyer prepared sulphide of cadmium and reported that it gave a beautiful yellow colour, rich, opaque and permanent; he commended it to artists especially for its ability to mix well with blues. Cadmium was nowhere abundant, but it was reliably found in small quantities in many zinc workings, which were then growing rapidly in number to meet the demand for brassware. The sulphide soon became a commercial pigment. Its attraction was not merely convenience of supply, but the range of colours it produced–more than any other single element. According to the level of various impurities, cadmium sulphide pigments run from a slightly muddied spring green through yellow and orange to an absurdly vivid red, various deeper reds and a dark maroon–practically the entire rainbow except for blue.

  These superior colours made themselves indispensable to painters. A few had quibbles about their supposed artificiality–William Holman Hunt complained that cadmium yellow ‘at the best is very capricious’–but most saw the bright, pure colours for what they were. The Impressionists, Post-Impressionists and above all the Fauvists made good use of cadmium–or, it would be more accurate to say, cadmium made possible these successive waves of artistic revolution. As each new tint became available, it powered in turn the yellow sunsets of Monet, the orange-soaked Arles interiors of van Gogh and Matisse’s Red Studio. People have romantically supposed that van Gogh was too hard up to buy the new pigments, while others believe the artist’s mental state may have been affected by his use of cadmium (although he was certainly also using more noxious pigments). What is sure is that he and his peers suddenly had access to a palette of colours of an intensity never seen before.

  In 1989, the United States Republican senator for Rhode Island, John Chafee, later chairman of the Senate environment committee, sought to ban the use of cadmium in pigments as part of a series of measures designed to reduce the risk of toxins from landfill waste sites leaching into ground water supplies. Sensitive souls across America found themselves torn between the interests of the environment on the one hand and artistic freedom on the other. Although the dangers of various metallic elements used in pigments were well known, the prospective legislation seemed to single out cadmium for the strongest disapprobation. One painter spoke of ‘chemical censorship’, and said that having to forgo cadmium colours would be like cooking without garlic.

  The vocal protests tended to obscure the fact that artists’ paints account for only a very small fraction of cadmium pigment use. Items such as colourful plastic washing bowls posed a far greater risk if they were disposed of thoughtlessly, and for these undemanding uses it was relatively easy to find safer pigments. But many painters felt that aesthetically there was simply no substitute for cadmium. The sad truth of the matter was that the wishes of artists no longer drove the pigment industry as perhaps they did during the Renaissance, and it now seemed that cadmium’s brief reign as the painter’s favourite pigment was about to be ended.

  After a lengthy campaign, though, America’s artists won a reprieve, and other countries that had been seeking to introduce greater restrictions on cadmium soon followed suit. Today painters are free to use their cadmium yellow and orange and red with the same abandon as Jackson Pollock and van Gogh. The colours–it is legally significant for their survival that they are referred to as colours, not as paints–the colours already bore labels in the United States advising of their chemical contents. Now they bear similar labels in European countries as well–an improvement on the situation before when some carried the confusing message: ‘health label: No health labelling required’.

  There is a reason why artists were provoked to such effective outrage, and it has nothing to do with the aesthetic merits of cadmium colour. For it is only when a painting is destroyed that the cadmium on its canvas can begin to find its way back into the environment. Artists claim their exemption from the general ban now in force on the use of cadmium in plastics and batteries and other mundane items based on the expectation that their paintings will not suffer this ignominious fate. Canvas is sufficiently expensive that artists tend to overpaint rather than throw out inferior work, and once a painting leaves the studio it tends to gain in value, which helps to ensure its survival. What had really roused America’s artists, then, was not the danger to the environment posed by cadmium pigments, nor the threat that they would lose a favourite colour, but the hurtful thought that their work might not in fact be treasured for ever.

  It seems beyond sad–almost a moralistic affront to our capacity for sensuous delight–that so many of the highly coloured chemicals should also be poisonous. This is true not only of the salts of cadmium but also of many long-known pigments such as yellow lead chromate and the vermilion of mercuric sulphide. Poisons in fairy tales often come in coloured bottles, or are coloured themselves. Christian Dior’s counter-intuitively marketed perfume Poison exploits this mythology in a purple glass bottle shaped like an apple.

  The basis for this association lies deep in evolutionary psychology and biochemistry. Humans and many species have evolved to be attracted to, yet also wary of, bright colours in nature. The colours may advertise ripe fruit and fresh meat or warn of poisonous berries and venomous creatures. Their chemical origin is generally quite different from that of manmade pigments based on heavy metals. The colours of fruit, for example, are based on yellow xanthophyll, the orange carotenes and purple anthocyanins, which are all organic compounds that contain no metallic elements. The same pigments give away the presence of such fairy-tale dangers as holly berries and the spotted red fly agaric toadstool (although the poisons they contain are not these pigments but different compounds again).

  How, then, do the metal-based pigments of the artist come to be poisonous? There are various mechanisms. Some salts, such as the chromates, are powerful oxidants, which release carcinogenic oxygen radicals into the body. Others mess with biochemical pathways where vital metals such as iron and zinc are important: for example, cadmium can deprive the body of zinc by binding with certain proteins in its place; in the same way, chromium, cobalt and manganese can all displace iron from the blood plasma. The details of this biochemistry are not yet fully understood, but there is excitement that humankind might one day turn this system to its own and nature’s advantage. By harnessing certain proteins, we may be able selectively to recover valuable heavy metals with which we have polluted our environment, including not only pigment elements such as cadmium and chromium but also radioactive uranium and plutonium.

  Stromeyer performed his public duties well when he saved purchasers of
the apothecary’s contaminated zinc oxide preparation from unnecessary exposure to cadmium. Elsewhere, the danger has been revealed too late. Cadmium yellow, orange and red may be one thing, but ‘cadmium blues’ is quite another. This is the term that has come to describe the first cold-fever symptoms of those exposed to chronic high levels of the metal, either from soluble salts or from the inhalation of cadmium vapour. Industrial exposure poses the greatest risk. Welders working to dismantle a temporary metal structure in the unventilated space inside one of the towers of the Severn Bridge provide a grim illustration of this. The men used oxyacetylene torches to cut through bolts that were plated with cadmium. The next day they found difficulty in breathing and were taken to hospital, where one of them later died from poisoning due to inhalation of the metal vapour. In Fuchu, on the northern coast of Japan, hundreds of people succumbed to a bone-softening illness they called itai-itai (itai is Japanese for ‘ouch’), which turned out to be the result of high levels of cadmium in rice that had been grown downstream of a large zinc and silver mine. Relative to these risks, the risk that cadmium poses to artists is not great: the pigments used in paints are not very soluble, and so are not very efficiently absorbed by the body even if they are ingested.

  The artist’s studio is not the only arena where cadmium’s combination of colour and toxicity have provoked controversy. For years, I had been aware of a rumour that my local city of Norwich had received an unwelcome chemical visit in the night.

  We now know this is what happened. Thursday 28 March 1963 had been a fine day, and there was almost no cloud that evening when a Devon light aircraft set out on a path that would take it from Aldeburgh on the Suffolk coast on a west-northwesterly path over the county of Norfolk. The plane was loaded with 150 pounds of a specially prepared zinc cadmium sulphide pigment, which was released at an altitude of 500 feet at the point when the plane was judged to be passing upwind of Norwich. A light southwesterly breeze dispersed the fluorescent orange particles into an invisible haze. On the ground, at forty sites in and around the city, mysterious officials–they were from the Chemical Defence Experimental Establishment at Porton Down in Wiltshire, although they bore no such insignia on their protective clothing–took up positions, ready with collectors that would allow them to count the falling particles. From declassified government papers, it appears the aim of the exercise was to test the likely efficacy of methods of biological warfare. The fluorescent cadmium pigment was merely a convenient and supposedly innocuous tracer made up in a particulate form to resemble a potential biological agent. The Ministry of Defence ran many such tests from the mid 1950s–often, so as not to arouse undue attention, over the defence establishments themselves. But sometimes the officials deemed it necessary to select a more realistic target. This was the case at Norwich, where the idea was to see whether the particles would fall to ground in an urban environment against the current of warmed air rising from the densely clustered houses. On that Thursday evening, only lowish levels of the pigment reached the collector sites. The aerial trials were repeated four times in the cold early months of 1964.