Portrait de la marquise de Pompadour (Musée Antoine-Lécuyer; pastel study): a second Pompadour sheet in the fonds — the great commission's working residue: five years of sittings left their strata in Saint-Quentin, the Louvre's monument in preparatory section.

The Abbé Nollet (Alte Pinakothek, Munich): the Enlightenment's great electrical showman — the abbé whose Leyden-jar demonstrations jolted lines of monks for the court's delight — given the address at its most alert: science as sociability, the lecturer mid-explanation; Munich's first La Tour.

Jean Le Rond d'Alembert (Louvre): the Encyclopédie's geometer at thirty-six, the wit at its brightest — Diderot judged it perfection, and posterity concurs: of all the philosophe portraits this is the quickest, the address at thought's own speed. The Louvre's sheet is the 1753 Salon's surviving glory and the movement's definitive second face.

Mademoiselle Ferrand meditating on Newton (Alte Pinakothek, Munich): the philosophical amie of Condillac's circle at her table, Newton's volume open — the century's rarest subject: a woman shown thinking, the address suspended mid-idea. Munich's celebrated pastel has become, in modern accounts, La Tour's feminist exhibit: intelligence portrayed without apology or ornament.

Portrait de Jean-Jacques Rousseau (Musée Carnavalet): the citizen of Geneva in the 1753 image's Paris version — the portrait Rousseau first loved and later, in the Confessions' darkness, disowned as the cabal's property (the essay's chapter tells the quarrel); Carnavalet keeps the face the capital argued over.

Portrait of Louis de Silvestre (Getty Center; drawing): the old painter-director — Dresden's court painter home in retirement, newly head of the Académie — drawn by his junior with professional piety: the guild's generations, one hand recording another.

Marc-René, marquis de Voyer d'Argenson (Musée Antoine-Lécuyer): the war minister's son, army man and famous connoisseur-collector — the enlightened amateur whose stables and galleries fed Diderot's circle: the client as fellow-expert, addressed accordingly.

Louis de Silvestre (Musée Antoine-Lécuyer): the finished pastel of the académie's elder — the drawing's Getty state carried to completion in the fonds: the pair, split between California and Picardy, document the workshop's route from seizure to statement.

Jean Monnet (Musée Antoine-Lécuyer): the impresario of the Opéra-Comique — theatre's great fixer, memoirist of the backstage century — in the fonds' theatrical wing: the entertainment world that gave La Tour his other clientele and his companion.

Marie-Josèphe de Saxe, dauphine (Musée Antoine-Lécuyer): the dauphine again in the workshop archive — the royal repetitions' Saint-Quentin stratum: the family's faces, kept in versions as the commissions flowed.

Marie Fel (Musée Antoine-Lécuyer): the great soprano — his companion of decades — in the finished portrait of 1757: the célèbre préparation's public sister. Love's likeness at Salon finish: the address, for once, has an answer built in; the fonds keeps both states, the caught and the composed, of the one face that stayed.

Portrait of the engraver Georg Friedrich Schmidt (ex-Demidov collection): the Berlin engraver who reproduced the age's portraits — including La Tour's — portrayed by the master he multiplied: the media economy's two ends, plate and pastel, face to face.

Louis, dauphin of France (Musée Antoine-Lécuyer): the serious heir in the workshop's late version — the royal file's Saint-Quentin continuation as the 1760s court commissions concentrated on the dauphin's growing family.

Louis-Joseph-Xavier, duc de Bourgogne — tête d'expression (Musée Antoine-Lécuyer): the dauphin's eldest son, dead at nine in 1761 — the head study made in the child's last year: the fonds' saddest sheet, royal childhood at préparation intimacy, kept by the artist as the court mourned.

Marie-Josèphe de Saxe with her son the duc de Bourgogne (Musée Antoine-Lécuyer): mother and doomed child together — the dynastic double portrait in the workshop state: the dauphine's file and the boy's, joined; within a year the composition was a memorial.

The picture

Pastel on blue-grey paper mounted on canvas, Museu Nacional d'Art de Catalunya, Barcelona. Pierre-Louis Laideguive, Parisian notary — a professional man of the robe's practical rank, no financier-prince — sits half-length in dark coat and neat wig, papers at hand, the face turned to the viewer with the mature La Tour address in its gravest register: attention complete, the smile held at the eyes only, the notary's professional virtues — discretion, exactness, the keeping of other men's secrets — legible in the set of the mouth. Exhibited at the Salon of 1761, it is the principal La Tour in Spain and the MNAC's key French eighteenth-century picture.

The bourgeois La Tour

The picture's interest begins with its rank. The famous La Tours are kings and philosophes; the working La Tour, Salon by Salon, portrayed precisely such men as Laideguive — the notaries, magistrates, doctors and fermiers of professional Paris — and the essay's phrase for his politics, the democracy of attention, is nowhere better tested: the notary receives exactly the apparatus the king received — the woven flesh, the double catch-light, the address at talking distance — with the rhetoric adjusted only to temperament: no dazzle, no accessories of wit; instead the professional's balanced, receiving look, the face of a man to whom one is about to entrust a will. Critics of the 1761 Salon singled the portrait out for truth (the year's entries were thin — the late phase beginning — and Laideguive stood among the proofs the machine still worked); modern criticism values it for the same quality under a sharper name: it is one of the most convincing portraits of listening in European art — the reactive half of conversation, which portraiture almost never attempts, given entire.

To Barcelona

The pastel's road to Catalonia ran through the post-Revolutionary dispersals and the nineteenth-century trade to the great Barcelona collections (the Cambó bequest's era of French acquisitions built the MNAC's old-master wing), and its presence there has a pedagogical consequence the museum understands: Iberia's public collections are nearly empty of French pastel — Spain's eighteenth century looked to Mengs and Goya — and Laideguive stands alone as the peninsula's demonstration of the medium at mastery: generations of Spanish visitors have learned what pastel could be from this one discreet notary, which would have amused the sitter's profession and satisfied the artist's vanity in equal measure.

What to look at

The eyes' engagement — the listening look: follow the picture's address and notice you have, involuntarily, begun composing what to say; the mouth's professional neutrality, warmth banked but present — compare Voltaire's irony or the Amiens laugh to measure how finely the register is tuned; the coat's dark economy against the paper's cool (the palette's sobriety itself a characterisation); the hands and papers, the tools of a documentary life given still-life dignity; and the condition — the surface's bloom intact after its long travels, the medium's paradoxical durability once more: the notary has kept his own file perfectly, as notaries should, and looks out from 1761 ready, imperturbably, for one more client. A pendant portrait of his wife is recorded in the literature; the pair's separation leaves Barcelona's notary listening, appropriately, alone.

Louis-Stanislas-Xavier, comte de Provence (Louvre): the dauphin's second son at seven — the future Louis XVIII, pastelled in the round-cheeked state: the Restoration's king in the ancien régime's nursery; the Louvre's royal-children file at its most historically loaded.

Princess Maria Christina of Saxony (Musée Antoine-Lécuyer): the dauphine's Saxon kin in the court file's widening circle — the Wettin connection that ran through the 1750s–60s commissions, archived at Saint-Quentin.

Clemens Wenceslaus of Saxony (Musée Antoine-Lécuyer): the dauphine's brother — the future archbishop-elector of Trier, in whose territories the Revolution's émigrés would later gather — in the Saxon file's 1763 entry: European dynastic portraiture's quiet traffic, by pastel post.

Portrait of Jean-Jacques Rousseau (Musée d'art et d'histoire, Geneva): the 1753 image's Geneva version — the citizen's face in the citizen's city: Rousseau's own Geneva keeps him in the portrait he (first) approved, beside the Liotards: the two Genevan glories of pastel, sitter and rival medium-master, one museum.

Portrait of Isabelle de Charrière (Musée d'art et d'histoire, Geneva): Belle de Zuylen — the brilliant Dutch letter-writer and novelist, Boswell's impossible love, Constant's future correspondent — at twenty-five: the pen's sharpest young woman met by the age's sharpest crayon; Geneva's sheet is the literary portrait's cross-border prize.

Isabelle de Charrière (Musée Antoine-Lécuyer): the Charrière likeness's fonds version — the workshop's record of the novelist's face: Saint-Quentin's literary wing extends past the philosophes to the age's great woman of letters.

Portrait of Jean-Jacques Rousseau (Musée Antoine-Lécuyer): the Rousseau of the studio stock — the face the engravers fought over, kept at source; with Geneva's and Carnavalet's versions, the triangulation of the century's most disputed likeness, all three from the one hand the sitter (mostly) trusted.

Self-portrait (Louvre): the old man's face in the last decade — the Amiens smile aged past confidence into something stranger: the address persisting as the addresser dims, the machinery perfect and the light behind it going. The Louvre's late sheet is the essay's dark chapter in one image — among the most unsettling self-portraits of the century.

Portrait of a man, called Monsieur d'Albespierre: an unidentified sitter of the professional rank — the address intact, the name worn away: the œuvre's memento of portraiture's usual fate, the face outliving the identity it was made to fix.

Portrait de la maréchale de Belle-Isle: the marshal-minister's wife, companion-piece to Carnavalet's duke — the pair's marriage of office and household in the standard pendant logic, the maréchale's sheet now recorded apart from her husband's.

Portrait of Marie-Josèphe of Saxony (Louvre): the dauphine's Louvre sheet — the court file's national-collection representative (Wikidata's placeholder date corrected here to her court years): the mother of three kings in the address that survives her dynasty.

Self-Portrait (Norton Simon Museum, Pasadena): the aging painter in the American collection — the self-examination's later file carried across the Atlantic in the twentieth century (the record's 1939 date marks its market passage, not its making): Pasadena's sheet lets the western hemisphere watch the smile's long wearing.

Charles Parrocel (Musée Antoine-Lécuyer): the battle-painter — horses and cavalry his trade — in the fonds' collegial file: the Académie's specialists, portrayed by the portraitist among them.

Charles Pinot Duclos (Musée Antoine-Lécuyer): the historiographer of France, moralist of the Considérations — the philosophes' shrewd, worldly secretary-general — in the address's knowing register: Duclos wrote the age's manners; the portrait is his thesis, returned with interest.

Jean-Joseph Cassanéa de Mondonville (Musée Antoine-Lécuyer): the composer-violinist — the Concert Spirituel's master, Rameau's rival in the querelle des bouffons — at performing brightness: the musical wing of the fonds, where La Tour's first world, his father's, kept its faces.

Portrait of Louis XV (Musée Antoine-Lécuyer; pastel): the king's face in the workshop stock — the royal likeness's Saint-Quentin state, kept through the decades of court work: the monarch, filed with the philosophes and the singers, in the democracy of the fonds.

Portrait of Mademoiselle Sallé (Calouste Gulbenkian Museum, Lisbon): the great dancer — Sallé of the expressive reform, London's and Paris's argued-over étoile — in the theatrical file's Lisbon jewel: Gulbenkian's second La Tour pairs the financier Duval with the age's most intellectual dancer, money and movement, one cabinet.

Portrait of René Frémin (Louvre): the old sculptor — Versailles' and Spain's — near the end of a long career: the académie's senior generation received into pastel; the Louvre's sheet closes this catalogue's collegial file where the grand siècle shakes hands with the Salon age.