Some painters of the first part of the nineteenth century were fascinated by other themes. Nature, in its true state, unadorned by conventions, became a subject for study, and running parallel to this was the realization that painting could be the visual externalization of the artist's own emotions and feelings. These two aspects, which until this time had only been very tentatively touched upon, were now more fully explored and led directly to the innovations of the Impressionists and later painters.

Jean-Baptiste-Camille Corot (1796-1875) started to paint landscapes that were fresh, direct and influenced as much by the unpretentious and realistic country scenes of seventeenth-century Holland as by the balanced compositions of Claude. His loving and attentive studies of nature were much admired by later artists, including Monet.

At the same time a whole group of painters developed similar attitudes to landscape and nature, helped greatly by the practical improvement of being able to buy oil paint in tubes rather than as unmixed pigments. Known as the Barbizon School after the village on the outskirts of Paris around which they painted, they soon discovered the joy and excitement of plein-air (open-air) painting.

Théodore Rousseau (1812-67) was their nominal leader, his paintings of forest undergrowth and forest clearings displaying an intimacy that came from the immediacy of the image. Charles-François Daubigny (1817-78), like Rousseau, often infused a sense of drama into his landscapes.

Jean-François Millet (1814-75) is perhaps the best-known associate of the Barbizon group, though he was more interested in the human figure than simple nature. Landscapes, however, were essential settings for his figures; indeed, his most famous pictures are those exploring the place of people in nature and their struggle to survive. The Sower , for instance, was a typical Millet theme, suggesting the heroic working life of the peasant. As is so often the case for painters touching on new themes or on ideas that are uncomfortable to the rich and powerful, Millet enjoyed little success during his lifetime, and his art was only widely recognized after his death.

The moralistic and romantic undertone in Millet's work was something that Gustave Courbet (1819-77) strove to avoid. Courbet was a socialist and his frank, outspoken attitude led to his being accused of taking part in the destruction of the column in Paris's place Vendôme after the outbreak of the Commune and, eventually, to his exile. After an initial resounding success in the Salon exhibition of 1849, he endured constant criticism from the academic world and patrons alike: scenes of ordinary life, such as the Funeral at Orléans , which he often chose to depict, were regarded as unsavoury and deliberately ugly.

But Courbet had a deep admiration for the old masters, especially for Rembrandt and the Spanish painters of the seventeenth and eighteenth centuries. This link with tradition was probably one of the underlying themes of his large masterpiece, The Studio , which was emphatically rejected by the jury of the 1855 Exposition Universelle, and in which Courbet portrayed himself, surrounded by his model, his friends, colleagues and admirers, among them the poet Baudelaire. Courbet subsequently decided to hold a private exhibition of some forty of his works, writing at the same time a manifesto explaining his intentions of being true to his vision of the world and of creating "living art". Writing the word Realism in large letters on the door leading to the exhibition, he stated his intentions and gave a label to his art.