The term 'Luncheon on the Grass Painter' refers to the French painter Edouard Manet. Manet was a prominent figure in the 19th century art world, and is best known for his painting 'Le dejeuner sur l'herbe' (Luncheon on the Grass). He was a leader of the Realist movement, which sought to depict everyday life in a realistic manner. Manet's works often featured scenes of modern life, and he was one of the first painters to incorporate elements of photography into his paintings. Manet's influence can be seen in the works of many later artists, and his painting 'Le dejeuner sur l'herbe' remains one of the most iconic works of the Realist movement.