For most of European painting's history, the color blue was a luxury measured out like spice. The most brilliant blue, ultramarine, was ground from lapis lazuli, a stone quarried in a single region of what is now Afghanistan and carried thousands of miles by traders. By the time it reached a painter's workshop in Florence or Bruges, it could cost more than gold by weight. Patrons wrote the pigment into their contracts, specifying that the Virgin's robe be painted in genuine ultramarine and not a cheaper substitute such as azurite, which grayed over time. A painter's willingness to lavish ultramarine on a work was therefore read as a sign of devotion and expense at once. This economics of color quietly shaped what viewers saw. Because blue was reserved for the most honored figures, its very presence in a painting told the eye where to look before the subject was consciously understood. When a synthetic blue was finally manufactured in the eighteenth century, cheap and abundant, painters could at last scatter the color freely across skies and rivers. Something was gained in that freedom, and something—a certain hierarchy of attention built into the palette itself—was quietly lost.