Origin: Mid-19th century, specifically in France during the 1840s
Pioneers: Gustave Courbet, Jean-François Millet, Honoré Daumier, Édouard Manet
Related Movements: Hyperrealism, Photorealism, Social Realism
Realism in the arts is generally the attempt to represent subject matter truthfully, without artificiality and avoiding speculative and supernatural elements. The term is often used interchangeably with naturalism, although these terms are not synonymous. Naturalism, as an idea relating to visual representation in Western art, seeks to depict objects with the least possible amount of distortion and is tied to the development of linear perspective and illusionism in Renaissance Europe. Realism, while predicated upon naturalistic representation and a departure from the idealization of earlier academic art, often refers to a specific art historical movement that originated in France in the aftermath of the French Revolution of 1848. With artists like Gustave Courbet capitalizing on the mundane, ugly or sordid, realism was motivated by the renewed interest in the common man and the rise of leftist politics. The realist painters rejected Romanticism, which had come to dominate French literature and art, with roots in the late 18th century.
In 19th-century Europe, "Naturalism" or the "Naturalist school" was somewhat artificially erected as a term representing a breakaway sub-movement of realism, that attempted (not wholly successfully) to distinguish itself from its parent by its avoidance of politics and social issues, and liked to proclaim a quasi-scientific basis, playing on the sense of "naturalist" as a student of natural history, as the biological sciences were then generally known...
When used as an adjective, "realistic" (usually related to visual appearance) distinguishes itself from "realist" art that concerns subject matter. Similarly, the term "illusionistic" might be used when referring to the accurate rendering of visual appearances in a composition. In painting, naturalism is the precise, detailed, and accurate representation in art of the appearance of scenes and objects. It is also called mimesis or illusionism and becomes especially marked in European painting in the Early Netherlandish painting of Robert Campin, Jan van Eyck and other artists in the 15th century. In the 19th century, Realism art movement painters such as Gustave Courbet were not especially noted for fully precise and careful depiction of visual appearances; in Courbet's time that was more often a characteristic of academic painting, which very often depicted with great skill and care scenes that were contrived and artificial, or imagined historical scenes. It is the choice and treatment of subject matter that defines Realism as a movement in painting, rather than the careful attention to visual appearances...
Source: Wikipedia