While long attributed to the Flemish painter Jan van Eyck in the 15th century, oil paint was actually used in Afghanistan as early as the 7th century for cave paintings. However, Van Eyck and his Northern Renaissance contemporaries perfected the medium for fine art. By mixing pigments with drying oils like linseed or walnut oil, artists could achieve a level of detail and luminosity impossible with 'egg tempera.' Oil paint dries much slower than tempera, allowing artists to blend colors directly on the canvas and apply multiple translucent layers (glazes) to create depth and realistic textures, such as velvet or skin. This technical shift allowed for the intense realism seen in works like 'The Arnolfini Portrait,' fundamentally changing the trajectory of Western painting toward the capture of light and atmosphere.