Impasto

Impasto (Italian for "dough" or "paste") describes paint applied thickly enough to stand proud of the canvas surface, retaining the visible ridges and furrows of the brush or palette knife. Unlike glazing's smooth transparency, impasto is prized for its tactile, sculptural presence and its ability to catch raking light, giving a painting a physical dimensionality that changes with viewing angle. Van Gogh is its most famous practitioner, loading pigment straight from the tube to give The Starry Night's swirling sky its churning, almost carved texture — a technique that also makes his paintings notoriously difficult to reproduce convincingly, since a flat print cannot replicate the raised paint's interaction with real light.