Though it was half-a-century ago, it's as clear to Edouard Adam as day. "Here, at that time, there were tiroirs full of different pigments," says M. Adam, waving to a patch of wall and miming a cabinet with his hands. "I took one of them out like this and, like this, I said 'Follow me'." I pad after him, the old man carrying his spectral drawer, through to the storeroom of a Paris shop. "There was no ceiling here then," he says. "Just daylight through a glass roof, north light - Jérôme, give me some bleu de Prusse, please - and I said to him: 'You have only two choices. It's either this'" - Adam throws the Prussian Blue onto a sheet of white paper - "'or this'." He empties the contents of the second jar onto the table and we stand back, staring at the two small mounds of powder. "It's as I had said to him on the way back from La Coupole: that's your choice, between these two. You have to decide, Yves."
If a new show at the Barbican Art Gallery is right, then I've just seen, re-enacted in this close room, one of the seminal moments of modern art. The contents of Adam's second jar is a powdered pigment known in French as bleu d'outremer, in English as ultramarine; the man he showed it to was Yves Klein. The outcome of this moment was a new colour - International Klein Blue, IKB - and the outcome of that colour was a way of thinking that has shaped the art of everyone since, from Andy Warhol to Anish Kapoor, from Joseph Beuys to William Eggleston. Maybe.
Let's consider what we've just seen. It's 1955. Klein, a Rosicrucian, fourth-dan judo expert and budding artist from Nice, is 26 or 27; Adam, a third generation marchand de couleur, or colour-man, is three years younger. His grandfather, Gaston Adam, set up shop here at 11 boulevard Edgar Quinet in 1898. Albert, the oldest of Gaston's five boys, took over the business in the 1920s and Edouard, his son, born above the shop, followed in the early 1950s. Chez Adam pre-empted the avant-garde's debouch south from Montmartre into Montparnasse before the Great War. Picasso, who moved in around the corner on the rue Vaugirard, became a customer in 1912, and the family has served every artist who is any artist since: Braque, Derain, Fernand Léger, Max Ernst, Chagall, Dalí, Vlaminck, Francis Bacon ("a shy man, fragile"), Robert Motherwell.
Adam wears the trademark black turtle-neck of 1950s Montparnasse, still lives over the shop where he was born. What he loves more than anything is - a glorious word - to tripatouiller : to tinker, to meddle. Artists have ideas, he makes them work. Calder's mobiles are crazing in the sun? Adam will run him up a little vernis that sorts the problem out. Dubuffet can't get a sticky enough impasto? Edouard tripatouilles with fish-oil and invents a medium called Pierrolin that allows the old man to be as informel as he likes. But it is Klein who intrigues him, who becomes his friend. What first draws the young artist to Adam's attention is his unusual consumption of sheepskin rollers; when Edouard asks Yves about it, it turns out that Klein, typically, can't be bothered to wash them and throws them away once he's used them. One day, strolling back again from La Coupole, the pair stop in front of the window chez Adam to look at a display of sponges Edouard has had installed there. In a fit of generosity, he offers Yves his pick; Yves, also typically, chooses the biggest, a giant of the Porifera world. A few weeks later, he drops by the shop to tell Adam that he's sold it in London, dyed, for £120.
This is to run ahead, though. What has happened in the meantime is that Yves has told Edouard of his search for the perfect blue - he'd already experimented with pink and orange - and Edouard has faced Yves with a choice: bleu de Prusse or bleu d'outremer. There was, says Adam, no contest, and you can see why. Prussian Blue is sombre, good for shadows. Even in this windowless room, ultramarine glows.
But there are problems. When the powdered pigment is mixed with the traditional binder, rabbit glue - Adam mimes bunny-ears - the light goes out of its eyes. Klein is mortified: "Each grain of colour seemed to have been individually killed," he wrote later. "The magic colour had disappeared." And so his marchand de couleur set about tinkering, dabbling with this and that until, meeting a chemist from Rhône-Poulenc, he finds a polyvinyl acetate resin called Rhodopas M, used for waterproofing maps. Mixed with ultramarine, Rhodopas allows the powdered blue to retain its granular look, its matt depth. In 1960, Klein patents the new pigment under the number 63471 and the name, International Klein Blue.
It is quite possibly the only work of Klein's you'll be able to name, by far the most famous thing he ever did. And, of course, he didn't do it. We can't hold that against him - nobody imagines Grace Kelly ever stitched a Kelly Bag - but it does raise the question of just what Klein's legacy is.
According to the Barbican's new show, "Colour After Klein" , it is the broad freeing of individual colours from the vassalage of function. Before Klein, blue had to justify its place in art: delineate the Virgin's robe, light the sky, suggest bucolic peace. After him it could just be, an existential thing, self-answering; or, in Klein's word, "absolute".
This is nonsense on several counts. Malevich had begun working in single colours a decade before Klein was born and artists such as Robert Rauschenberg were painting true monochromes a decade before IKB. Klein's blue - Adam's blue - is lustrous and deep: but it is a finish as much as it is a colour, standard synthetic ultramarine rendered granular and matt. You can bring all kinds of metaphors to it, recall Klein's upbringing under a Mediterranean sky or his amazement at Giotto's frescos in Assisi. But each one makes his blue slightly less pure, marginally more kitsch. As Edouard Adam recalls, Klein's earlier interest in pink reflected his fondness for his tantine, Rose. It's an unlikely basis for revolution.
The question, really, is where the stress falls in IKB: is it IKB or IKB? For my money, it's the latter. I very much doubt that Titian called Titian Red Titian Red, although he probably had a better claim to do so than Klein did Klein Blue. But then Titian lived in a time before branding. As with the Kelly Bag, IKB is about fame rather than facture, about the power of labels.
For by 1955 (and certainly by 1960), Klein had turned himself into a commodity. He made pictures by getting naked models - pinceaux vivants - to roll on fabric while smeared in IKB: "It took a long, long time to get those girls clean," says Edouard Adam, with a roguish wink. In April 1958, Klein had held the notorious first night of his show, Le Vide ("The Void"), which members of France's Republican Guard were hoodwinked into attending in full dress uniform. Guests were fed on a cocktail - mixed, naturally, by La Coupole - made up of gin, Cointreau and a dye called methylene blue. As Klein had hoped, they pissed IKB for a week.
He had decorated the foyer of the theatre at Gelsenkirchen in Germany with a vast frieze of sponges dipped in International Klein Blue, descendants of the one filched from Adam's shop window. ("Yves drew a square one metre by one metre on the shop floor and filled it with éponges," Adam recalls. "Then he turned to my sponge dealer, a Greek, and he said 'I'll have a hundred of those'. It's the first time art sponges had ever been sold by the square metre.") And he had surrounded himself by what Adam calls "un cinéma": a claque of admirers - "hystériques," says Adam - who sat at his table at La Coupole and stoked his ego.
Klein's real bequest to today's art may not, in other words, be the cult of colour so much as the cult of celebrity. There is a straight line to be drawn from his Gelsenkirchen frieze to Tracey Emin's bed, from the blue Adam invented for him to the factory-made vitrines of Damien Hirst. It's the K in IKB that matters.
I like to think of Klein's blue alongside another bespoke colour, the Braunkreuz or "Brown-cross", run up for his fellow self-publicist, Joseph Beuys. Where Klein's blue was joyfully synthetic (to the point, as it turned out, of being toxic to breathe), Beuys's brown was made of eco-friendly rust and hare's blood. Where the Frenchman's ultramarine draws the eye, the German's shit-brown appeals to the mind. And where Beuys's brown remained reticently anonymous, IKB was IKB.
What was Klein like? Edouard Adam mulls over the question and says, "A charmer, a seducer. He had those eyes, you know, that innocent smile: but he was ambitious beyond measure. He pushed himself to be the best - took benzedrine at first so that he would win at judo and then, after he'd stopped the judo, he went on taking it, more and more.
"While he was burning it up, he was OK; but afterwards... hop." Adam shrugs. "Two weeks before he died, he came to the shop and said, 'I've had a heart attack. The doctor says I've got to start working on a smaller scale.' But it wasn't in his nature." Klein had a second attack in June 1962 and died in front of his wife, pregnant with their first child. He was 34.
I ask Edouard Adam if he wishes he'd had a colour named after him. He thinks about it for a while and says, "I'm not into honours. I know all about art, the materials, the techniques, the history. Sometimes it gets me here" - he touches his head - "sometimes here" - he slaps his chest - "and sometimes here, in the tripes. But no work of art has ever been as interesting to me as the man who made it." Then he pauses for a bit and says, "Well, there is this violet - there are violets and violets, of course - but an ethereal kind of violet. You can imagine it coming down from the sky like a pillar, entering through your head and filling up your entire body. It's a magnificent colour, this violet." m
'Colour After Klein': Barbican Art Gallery, London EC2 (0845 1207550), to 11 SeptemberReuse content