The steel magnate Henry Clay Frick may have cared little for people, but he had a soft spot for artists, and he venerated James McNeil Whistler. The legacy of that passion is the Frick Collection’s inventory of Whistler prints, paintings and pastels, normally distributed among various rooms and storage vaults, and now gathered together in a small but luminous exhibition.

There is a revealing abyss between the show’s hushed atmosphere and Whistler’s brash personality. The artist enjoyed the fact that a well-placed provocation could send London into a tumult of outrage. He cast himself as a brave revolutionary, wiping away fusty sentimentalities and focusing on dispositions of form and colour. The Frick has pickled him in reverence, and in the mansion’s opulent precincts, Whistler’s tulle-swathed ladies and views of Venice have the gravitas of Old Masters. It is a betrayal, in a way, but an illuminating one: in spite of his protestations, Whistler was competing with his forebears, and holding his own. Frick placed him with Rembrandt and Velázquez in his esteem, and it’s hard to imagine that Whistler would have demurred.

Detail from ‘Symphony in Flesh and Pink: Portrait of Mrs Frances Leyland, 1872-1873

Whistler’s bursts of pugnacious rhetoric drew attention to himself and distracted from his pictures. “Art should be independent of all claptrap – should stand alone, and appeal to the artistic sense of the eye or ear, without confounding this with emotions entirely foreign to it, as devotion, pity, love, patriotism,” he pronounced. His famous portrait of his mother was not, he signalled, a portrait at all, but an “Arrangement in Grey and Black” – a formal exercise conducted with a familiar female configuration.

In his witty, truculent tone, he declared the independence of art from experience. He believed his art occupied an elevated orbit, always progressing towards perfection, a philosophy he advertised in lectures, letters, articles, books and even in court. These polemics were aimed at Victorian critics – particularly John Ruskin – who judged paintings according to their fidelity to nature, their moral content, and the labour involved in their creation. Whistler goaded his opponents to furious sputterings, which he cleverly harnessed to promote himself.

Ruskin obliged. The sage attacked “Nocturne in Black and Gold: the Falling Rocket,” a moody view of fireworks over the Thames, with some verbal pyrotechnics of his own: “I have seen, and heard, much of Cockney impudence before now; but never expected to hear a coxcomb ask two hundred guineas for flinging a pot of paint in the public’s face.” Whistler successfully sued Ruskin for libel, though the nominal damages (a single farthing) ultimately forced him into bankruptcy.

Punch produced a parody of the case, “Penny Whizzler vs Rubskin,” which concluded that “Mr Penny Whizzler should rather thank Mr Rubskin for having given him such an opportunity as this has been, for informing the general public of his existence, of which the general public was probably not aware”.

Whistler did not need a courtroom to stir up buzz. Born in Lowell, Massachusetts, he grew up in tsarist Russia, and arrived in London in 1859, a full-fledged cosmopolitan eccentric, deeply insecure about his gifts. He neutralised ridicule by courting it, wearing ostentatious suits, an ever-present monocle, and headgear that set off the white streak in his coiffed black curls. “Wait till you see me in an amazing hat!” he wrote to his wife in the early 1890s. “I am going to seem something quite new in London!!!” An elaborately cultivated moustache accented his angular features.

He was a virtuoso of the self-serving bon mot. Asked by a matron whether he believed genius to be hereditary, he replied: “I can’t tell you, Madam; heaven has granted me no offspring.”

With his feisty egotism, his Cyrano-like swagger and penchant for abstract titles, Whistler made himself hard to defend. The poet Algernon Swinburne wrapped his praise in irony, poking fun at the painter’s defiance. “It is true,” he wrote, “that Mr Whistler’s own merest ‘arrangements’ in colour are lovely and effective; but his portraits, to speak of these alone, are liable to the damning and intolerable imputation of possessing not merely other qualities than these, but qualities which actually appeal – I blush to remember and I shudder to record it – which actually appeal to the intelligence and the emotions, to the mind and heart of the spectator.” Behind the bluster, Swinburne was saying, lay psychological depth and searing expressivity.

Frick understood those qualities. He bought a dozen etchings of Venice, which combine immediacy with meticulous observation. Instead of dwelling on the city’s stately grandeur, in the manner of Guardi and Canaletto, Whistler floated on the lagoon or plunged down alleyways to capture the vibrancy of urban life in lines that seem to quiver in the warm, moist air.

As Swinburne pointed out, the bluff Whistler was equally perceptive about people. He captured the puritan pathos in his mother, and he found a kindred spirit in Robert de Montesquiou-Fézensac, whom he portrayed in an “Arrangement in Black”. The aristocratic dandy served as the model for three indelible literary characters: Proust’s decadent aesthete Baron de Charlus; Jean des Esseintes, the debauched hero of Huysman’s À rebours; and Wilde’s evil narcissist, Dorian Gray. Whistler presents him as a glamorous dark lord, set against an inky background and enveloped in the charcoal of his fine suit. Dusky hair fuses with the surrounding soot, and only a pale face, snowy cravat and long-fingered glove alleviate the elegant gloom.

Had Whistler been interested in blackness alone, he would not have importuned Montesquiou for more than a hundred sittings, in which he painted, rubbed out, dabbed and erased again. In the arch of the back and the jut of a chin, he conveys the man’s presumptions, aloofness, refinement, and narcissism. The glove is an everyday accessory, but it evokes the accoutrements of the Spanish noblemen immortalised by Velázquez. So does the Malacca cane, which thrusts forwards like a weapon, as if to keep the rabble at bay. Whistler endowed the rakish Montesquiou with greatness, and Montesquiou returned the favour. Reflected in the subject’s gaze, we see a painter mesmerised by the troublesome complexities of what he called “claptrap” and the rest of us might call life.