Mark Rothko, ‘Untitled (lavender and Green)’, 1952. The painting sold within its estimate for $20 million. Image courtesy Sotheby’s

Mark Rothko, 'Untitled (lavender and Green)', 1952. The painting sold within its estimate for $20 million. Image courtesy Sotheby's

Mark Rothko, ‘Untitled (lavender and Green)’, 1952. The painting sold within its estimate for $20 million. Image courtesy Sotheby’s