he and his friend Claude Monet discovered that the color of shadows is not brown or black, but the reflected color of the objects surrounding them, an effect known today as diffuse reflection. Several pairs of paintings exist in which Renoir and Monet worked side-by-side, depicting the same scenes (La Grenouillère, 1869). One of the best known Impressionist works is Renoir's 1876 Dance at Le Moulin de la Galette (Bal du moulin de la Galette). The painting depicts an open-air scene, crowded with people at a popular dance garden on the Butte Montmartre close to where he lived. The works of his early maturity were typically Impressionist snapshots of real life, full of sparkling color and light. By the mid-1880s, however, he had broken with the movement to apply a more disciplined formal technique to portraits and figure paintings, particularly of women. It was a trip to Italy in 1881 when he saw works by Raphael, Leonardo da Vinci, Titian, and other Renaissance masters, that convinced him that he was on the wrong path. At that point he declared, "I had gone as far as I could with Impressionism and I realized I could neither paint nor draw". For the next several years he painted in a more severe style in an attempt to return to classicism. Concentrating on his drawing and emphasizing the outlines of figures, he painted works such as Blonde Bather (1881 and 1882) and The Large Bathers (1884–87; Philadelphia Museum of Art) during what is sometimes referred to as his "Ingres period". After 1890 he changed direction again. To dissolve outlines, as in his earlier work, he returned to thinly brushed color. From this period onward he concentrated on monumental nudes and domestic scenes, fine examples of which are Girls at the Piano, 1892, and Grandes Baigneuses, 1887. The latter painting is the most typical and successful of Renoir's late, abundantly fleshed nudes. A prolific artist, he created several thousand paintings. The warm sensuality of Renoir's style made his paintings some of the most well-known and frequently reproduced works in the history of art. The single largest collection of his works—181 paintings in all—is at the Barnes Foundation, in Philadelphia. Catalogue raisonné A five-volume catalogue raisonné of Renoir's works (with one supplement) was published by Bernheim-Jeune between 1983 and 2014. Bernheim-Jeune is the only surviving major art dealer that was used by Renoir. The Wildenstein Institute