John Keats addressed a poem to a Grecian urn: "Thou still-unravish'd bride of quietness!/Thou foster-child of Silence and slow Time,/Sylvan historian, who canst thus express/A flowery tale more sweetly than our rhyme." The figures painted on the urn inspired in Keats the type of reverie that he usually saved for things like Indolence, or Seeing a Lock of Milton's Hair. Why did the Grecian urn have such an effect? Can painting really express a flowery tale more sweetly than rhyme?

Poetic ekphrasis (the practice of writing descriptions of visual art) has been around since Book XVIII of the Iliad, when Hephaestus fashioned an ornate shield for Achilles. Dante and Virgil followed Homer like ducklings into this practice, but they wrote chiefly about sculpture and reliefs. Poets didn't pay much explicit attention to painting until the 20th century—W. H. Auden and William Carlos Williams both wrote about Pieter Brueghel the Elder, and then John Ashbery threw his lot in with Parmigianino.

Ashbery's 1974 masterpiece, "Self-Portrait in a Convex Mirror," gets to the bottom of things. Poetry has always meddled in the substitution of words for images; previous ekphrastic works described, reveled in, or teased out the motivations behind visual art. Ashbery's work may be the first to substitute words for a particular painting, attempting to mirror not just its appearance but its effect on its audience. "Self-Portrait in a Convex Mirror" is 15 pages of beautiful poetry made even more beautiful by the fact that it inspires in readers a rare artistic synesthesia that less ambitious works couldn't bring about. Therefore, I'm sharing this with you for nothing but sheer, crosshatching pleasure.

The title of the poem comes from a 1524 painting by Francesco "Parmigianino" Mazzola—the mannerist prankster behind the infamous Madonna of the Long Neck, and a Vision of Saint Jerome featuring a Christ child who looks suspiciously like a chorus girl. These paintings indulge in fanciful interpretations of the human form, but Self-Portrait in a Convex Mirror depicts with great accuracy (on a convex block of wood) a distorted reflection.

Sixteenth-century Italian painting existed solely for the dispersal of glory—to God, to man, to whoever commissioned or displayed the work. Parmigianino's self-portrait glorifies painting itself, its possibilities and proclivities. The sheer ostentation of its form consigns it to the realm of self-referential art, but Parmigianino keeps all the fancy stuff around the edges—his head is painted plain in the middle of its whorling room. That head takes up no more than a few of the painting's nine inches. Writes Ashbery, "There is in that gaze a combination/Of tenderness, amusement, and regret, so powerful/In its restraint that one cannot look for long."

Parmigianino lets us see what an artist is doing when creating a self-consciously formalistic work, and it's not pretty. There's something lonely and small in virtuosity. The artist is a masturbator, looking inward for some perfect memory or something not yet encountered, "so as to perfect and rule out the extraneous/Forever." Ashbery's line break isn't an accident—Parmigianino strives for permanence in his portrait, the perpetuation of the creative process that moves (like masturbation) from tenderness to amusement to regret.

Ashbery's poem begins with a straightforward verbal depiction of its subject, then veers into musings about time and perception. The painting makes regular appearances throughout the poem, but always it appears differently in Ashbery's convex mirror. "This past/Is now here: the painter's/Reflected face, in which we linger, receiving/Dreams and inspirations on an unassigned/Frequency, but the hues have turned metallic,/the curves and edges are not so rich." With time bearing him ever further from the moment of Parmigianino's painting, Ashbery, too, resorts to virtuosity. He controls phrase, cadence, and mood the way Parmigianino controlled the room behind him. But he lets us see the poet as well, vulnerable at the center of his work.

A poet's job is to notice things (the decline of popular regard for poetry coincides with the rise of standup comedy), and a poet's words might put across what we miss in pigment. Paintings can knock us flat or blow us back, but they can't sneak up on us. Our eyes won't let us appreciate art when we're tired. Reading, on the other hand, is best done just before bed, or upon waking, in close proximity to dreams. Printed text is the most mediated of media, snaky and insinuating, exploiting our lowered defenses. Ekphrastic poetry is art criticism that aims at the subconscious; one great poem about a painting can change the way we look at painting altogether.

Distortions—visual and poetic—remain tethered to their subjects, but they say a lot more about the nature of looking itself. Step between the twin mirrors of poem and painting: You'll find yourself repeated forever, curving inexorably away, angling after that most distant reflection.

Read excerpts of Ashbery's poem.