"Monet and Renoir... concentrated... on the waters of the Seine sparkling... dissolving solid forms into dazzling patches of color. Monet... excelled at... light shimmering on the waves. He worked on the same pale ground favored by Manet but... highlighted... with vibrant pigments, some... newly invented... added... in small commas and dashes. Advances in chemistry... meant nineteenth-century painters possessed a much wider range of pigments... [M]any painters... [had] learned to tone down their works by coating them with transparent brownish glazes made from... ingredients... as bitumen. ...Painters who challenged this prejudice against color... notably Delacroix... found themselves reviled by conservative critics. ...The coruscating reflections in [Monet's] La Grenouillère canvases owed much to his use of pigments such as chromium oxide green and cobalt violet. The former... produced from a... reaction involving salts and , was manufactured... in 1862. Cobalt violet [was] invented in 1859 by... Jean Salvétat... Monet blended it with to create a shimmering water... He would eventually... regard this... pigment as an essential for capturing... light and shade: "I have finally discovered the color of the atmosphere... It is violet." ...Monet might never have discovered the true nature of the atmosphere without... chemists..."