The Autochrome process was an early method of color photography developed in the early 20th century. Introduced in 1907 by the Lumière brothers, it used a glass plate coated with tiny grains of colored starch, typically from potatoes, to create a color image. When exposed to light, these grains acted as filters, allowing only certain colors to pass through and form a colored photograph. To develop an Autochrome image, the exposed plate was processed in a darkroom, resulting in a positive transparency. This process was popular until the 1930s, when more advanced color film technologies emerged, making Autochrome less common in photography.