Helen Frankenthaler's Lavender Stop (1985) dates from what John Elderfield called the height of her powers. Three decades after Mountains and Sea (1952) introduced her soak-stain method and set American painting toward Color Field, she was in complete command of it — and working in the wide horizontal format, closest to traditional landscape painting, most prized in her work.

Nearly ten feet wide, the canvas is one soaked expanse of red and orange — deepest at the center, cooling to ochre at the bottom and edges, acrylic thinned to watercolor transparency on raw canvas. Just below the midpoint, a low band of lavender and pale blue runs in from the left, thickly worked into ridges, stopping short of the right edge. Flecks of white, jade, and rose drift across the field, which reads as a horizon without describing one.

Acquired in 1985 from André Emmerich Gallery, her longtime dealer, the painting has remained in private hands since. Frankenthaler's standing has only risen: MoMA's Helen Frankenthaler: A Grand Sweep was its first monographic show of her work since 1989, Kunstmuseum Basel has mounted the largest European survey to date, and the National Gallery of Art is organizing a traveling centenary retrospective for 2028. Mature paintings of this scale rarely reach the market.